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Tag: low-carb diets

  • Treating Hashimoto’s Disease (Hypothyroidism) Naturally with Diet  | NutritionFacts.org

    What were the results of a randomized, double-blind, placebo-controlled trial of a daily half teaspoon of powdered black cumin in Hashimoto’s patients?

    “Autoimmune thyroiditis, also known as Hashimoto’s thyroiditis, is an organ-specific autoimmune disorder,” where our body attacks our own thyroid gland, often leading to hypothyroidism due to destruction and scarring of the gland itself. We know there’s a genetic component, since identical twins are more likely to share the disease than fraternal twins. “However, even with identical twins, the concordance rate was only about 50%, emphasizing that important factors such as the environment play a role in disease pathogenesis.” Indeed, even if your identical twin, who has basically your exact same DNA, has the disease, there’s only like a flip of a coin’s chance you’ll get it. Genes load the gun, but the environment may pull the trigger.

    More than 90 synthetic chemicals were noted to show disruption of hormonal balance or thyroid dysfunction.” However, only a few such ‘pollutants show evidence that they contribute to autoimmune thyroid disease.” These include polyaromatic hydrocarbons. Smokers get a lot of them from cigarettes, but in nonsmokers, exposure comes almost entirely from food, as you can see below and at 1:18 in my video Diet for Hypothyroidism: A Natural Treatment for Hashimoto’s Disease. 

    Polycyclic aromatic hydrocarbons are primarily formed when muscle meats, such as beef, pork, fish, or chicken, are cooked using high-temperature methods, such as grilling. PBBs, polybrominated biphenols, are a type of flame-retardant chemical no longer manufactured in the United States, but are still found in the aquatic food chain. PCBs, polychlorinated biphenols, are used in a number of industrial processes and end up in people’s bodies, again, largely through the consumption of fish, but also eggs and other meats, as seen here and at 1:41 in my video.

    So, one might suspect those eating plant-based diets would have lower rates of hypothyroidism, and, indeed, despite their lower iodine intake, vegan diets tended to be protective. But they’ve never been put to the test in an interventional trial. A modification of the Paleolithic diet has been tried in Hashimoto’s patients, but it didn’t appear to improve thyroid function. What did, though, is Nigella Sativa. That name should sound familiar to anyone who’s read my book How Not to Diet or watched my live Evidence-Based Weight Loss presentation. Nigella Sativa is the scientific name for black cumin, which is just a simple spice that’s also used for a variety of medicinal purposes.

    In one study, Hashimoto’s patients received a half teaspoon of powdered black cumin every day for eight weeks in a randomized, double-blind, placebo-controlled trial. Not only was there a significant reduction in body weight, which is why I profiled it in my book, but the black cumin also significantly reduced the thyroid-stimulating hormone, a sign that thyroid function was improving. It even lowered the level of autoimmune anti-thyroid antibodies, as well as increased blood levels of thyroid hormone T3 in these Hashimoto’s patients. In addition, there was a significant drop in Interleukin 23, a proinflammatory cell signal thought to help promote the autoimmune inflammation of the thyroid, which “further confirms the anti-inflammatory nature of the plant.” And what were the side effects? There was a 17 percent drop in “bad” LDL cholesterol, as shown below and at 3:19 in my video.

    Given the fact that patients with Hashimoto’s may be at particularly high risk of developing heart disease, this is exactly the kind of side effects we’d want. “Considering these health-promoting effects of N. Sativa [black cumin], it can be considered as a therapeutic approach in the management of Hashimoto-related metabolic abnormalities.”

    A similar trial failed to find a benefit, though. Same dose, same time frame, but no significant changes in thyroid function. In contrast with the previous study, though, the study participants were not all Hashimoto’s patients, but rather hypothyroid for any reason, and that may have diluted the results. And it’s possible that telling patients to take the black cumin doses with their thyroid hormone replacement therapy may have interfered with its absorption, which is an issue similar to other foods and drugs, and why patients are normally told to take it on an empty stomach. Since there are no downsides—it’s just a simple spice—I figure, why not give it a try? The worst that can happen is you’ll have tastier food.

    Doctor’s Note:

    I get a lot of questions about thyroid function, and I am glad to have been able to do this series. If you missed any of the other videos, see the related posts below.

    For more on black cumin, see my book How Not to Diet and my presentation Evidence-Based Weight Loss. 

    Michael Greger M.D. FACLM

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  • Vegans and Iodine Deficiency Risk  | NutritionFacts.org

    Most plant-based milks are not fortified with iodine.

    “Adequate dietary iodine is required for normal thyroid function.” In fact, the two thyroid hormones are named after how many iodine atoms they contain: T3 and T4. “Given that iodine is extensively stored in the thyroid gland itself, it can safely be consumed intermittently,” so we don’t need to consume it every day. However, our overall diet does need a good source of it. Unfortunately, the common sources aren’t particularly health-promoting: iodized salt and dairy foods. (Iodine-based cleansers like betadine are used on cows “to sanitize the udders, resulting in leaching of iodine in the milk.”) Iodine may also be added to cattle feed, and some commercially produced breads contain food additives with iodine.

    If you put people on a paleo-type diet and cut out their dairy and table salt, they can develop an iodine deficiency, even though they double their intake of seafood, which can also be a source of iodine. What about those switching to diets centered around whole plant foods? They also cut down on ice cream and Wonder Bread, and if they aren’t eating anything from the sea, like seaweed or other sea vegetables, they can run into the same problem.

    A three-year-old’s parents reported striving to feed her only the healthiest foods, and her diet included only plant-based, unsalted, and unseasoned foods. She got no unprocessed foods, but she also got no vitamin supplementation, which could be deadly. Without vitamin B12, those on strictly plant-based diets can develop irreversible nerve damage, but in this case, a goiter arose first, due to inadequate iodine intake.

    In another case of “veganism as a cause of iodine-deficient hypothyroidism,” a toddler became ill after weaning. Before weaning, he was fine because his mother kept taking her prenatal vitamins, which fortunately contained iodine.

    Most vegetarians and vegans are apparently unaware of the importance of iodine intake during pregnancy, “for the neurodevelopment of the unborn child, similar to their omnivorous counterparts.” The American Thyroid Association and the American Academy of Pediatrics have recommended that women, even just planning on getting pregnant, should take a daily supplement containing 150 micrograms (mcg) of iodine, yet only 60 percent of prenatal vitamins marketed in the United States contain this essential mineral. So, despite the recommendations, about 40 percent of prenatal vitamins don’t contain it. “Therefore, it is extremely important that women, especially when pregnant, breastfeeding, or planning a pregnancy, read the labels of their multivitamin supplements to ensure that they are receiving an adequate amount of iodine.”

    Women of reproductive age have an average iodine level of 110 mcg/liter, which is fine for nonpregnant individuals, but we’d really like women to get at least 150 mcg/liter during pregnancy. (It’s basically a 24-hour urine test, in which iodine sufficiency is defined as 100 mcg/liter of urine in nonpregnant adults; the average vegan failed to reach this in the largest study done to date, one out of Boston.)

    The recommended average daily intake is 150 mcg per day for most people, which we can get in about a cup and a half of cow’s milk. Regrettably, plant-based milks aren’t typically fortified with iodine and average only about 3 mcg per cup. Although many plant-based milks are fortified with calcium, researchers found in the largest systematic study to date that only 3 out of 47 were fortified with iodine. Those that were fortified had as much as cow’s milk, but those that weren’t fell short, as you can see at 3:30 in my video Are Vegans at Risk for Iodine Deficiency?. 

    Plant-based milk companies brag about enriching their milks with calcium and often vitamins B12, D, and A, but only rarely are attempts made to match iodine content. The only reason cow’s milk has so much is that producers enrich the animals’ feed or it comes dripping off their udders. So, why don’t plant-milk companies add iodine, too? I was told by a food scientist at Silk that my carrageenan video played a role in the company switching to another thickener. Hopefully, Silk will see this video, too, and consider adding iodine, or maybe another company will snatch the opportunity for a market advantage.  

    The researchers conclude that individuals who consume plant-based milks not fortified with iodine may be at risk for iodine deficiency, unless they consume alternative dietary iodine sources, the healthiest of which are sea vegetables, which we’ll cover next.

    Doctor’s Note:

    This is the first in a four-video series on thyroid function. The next three are: 

    For more on iodine, see the related posts below.

    Michael Greger M.D. FACLM

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  • Eating to Keep Ulcerative Colitis in Remission  | NutritionFacts.org

    Plant-based diets can be 98 percent effective in keeping ulcerative colitis patients in remission, far exceeding the efficacy of other treatments.

    “One of the most common questions physicians treating patients with IBD [inflammatory bowel disease] are asked is whether changing diet could positively affect the course of their disease.” Traditionally, we had to respond that we didn’t know. That may now be changing, given the “evidence in the literature that hydrogen sulfide may play a role in UC,” ulcerative colitis. And, since the sulfur-containing amino acids concentrated in meat cause an increase in colonic levels of this rotten egg gas, perhaps we should “take off the meat.” Indeed, animal protein isn’t associated only with an increased risk of getting inflammatory bowel disease in the first place, but also IBD relapses once you have the disease.

    This is a recent development. “Because the concept of IBD as a lifestyle disease mediated mainly by a westernized diet is not widely appreciated, an analysis of diet in the follow-up period [after diagnosis] in relation to a relapse of IBD has been ignored”—but no longer. Ulcerative colitis patients in remission and their diets were followed for a year to see which foods were linked to the return of their bloody diarrhea. Researchers found that the “strongest relationship between a dietary factor and an increased risk of relapse observed in this study was for a high intake of meat,” as I discuss in my video The Best Diet for Ulcerative Colitis Treatment.

    What if people lower their intake of sulfur-containing amino acids by decreasing their consumption of animal products? Researchers tried this on four ulcerative colitis patients, and without any change in their medications, the patients experienced about a fourfold improvement in their loose stools. In fact, they felt so much better that the researchers didn’t think it was ethical to try switching the patients back to their typical diets. “Sulfur-containing amino acids are the primary source of dietary sulfur,” so a “low-sulfur” diet essentially means “a shift from a more traditional western diet (high in animal protein and fat, and low in fiber) to more of a plant-based diet (high in fiber, lower in animal protein and fat).” “Altogether, westernized diets are pro-inflammatory, and PBD [plant-based diets] are anti-inflammatory.”

    What can treatment with a plant-based diet do after the onset of ulcerative colitis during a low-carbohydrate weight-loss diet? A 36-year-old man lost 13 pounds on a low-carb diet, but he also lost his health; he was diagnosed with ulcerative colitis. When he was put on a diet centered around whole plant foods, his symptoms resolved without medication. He achieved remission. That was just one case, though. Case reports are akin to glorified anecdotes. The value of case reports lies in their ability to inspire researchers to put them to the test, and that’s exactly what they did.

    Until then, there had never been a study published that focused on using plant-based diets for treating ulcerative colitis. Wrote the researchers, a group of Japanese gastroenterologists, “We consider that the lack of a suitable diet is the biggest issue faced in the current treatment of IBD. We regard IBD as a lifestyle disease caused mainly by our omnivorous (Western) diet. We have been providing a plant-based diet (PBD) to all patients with IBD” for more than a decade and have published extraordinary results, far better than have been reported elsewhere in the medical literature to date. (I profiled some of their early work in one of the first videos that went up on NutritionFacts.org.) The researchers found a plant-based diet to be “effective in the maintenance of remission” in Crohn’s disease by 100 percent at one year and 90 percent at two years. What about a plant-based diet for relapse prevention in ulcerative colitis?

    “Educational hospitalization” involved bringing patients into the hospital to control their diet and educate them about the benefits of plant-based eating (so they’d be more motivated to continue it at home). “Most patients (77%) experienced some improvement, such as disappearance or decrease of bloody stool during hospitalization.” Fantastic!

    Here’s the really exciting part. The researchers then followed the patients for five years, and 81 percent of them remained in remission for the entire five years, and 98 percent kept the disease at bay for at least one year. That blows away other treatments. Those relapse rates are far lower than those reported with medication. Under conventional treatment, other studies found that about half of the individuals relapse, compared to only 2 percent of those taught to eat healthier.

    “A PBD was previously shown to be effective in both the active and quiescent stages of Crohn’s disease. The current study showed that a PBD is effective in both the active and quiescent stages of UC as well.” So, the researchers did another study on even more severely affected cases with active disease and found the same results, with plant-based eating beating conventional drug therapy by far. People felt so much better that they were still eating more plant-based food even six years later. The researchers conclude that a plant-based diet is effective for treating ulcerative colitis to prevent a relapse.

    Why? Well, plant-based diets are rich in fiber, which feeds our good gut bugs. “This observation might partly explain why a PBD prevents a variety of chronic diseases. Indeed, the same explanation applies to IBD, indicating that replacing an omnivorous diet with a PBD in IBD is the right approach.” 
     
    It’s like using plant-based diets to treat the cause of heart disease, our number one killer. Plant-based eating isn’t only safer and cheaper, but it also works better with no noted adverse side effects. Let’s compare that to the laundry list of side effects of immunosuppressants used for ulcerative colitis, like cyclosporine, which you can see below and at 5:40 in my video. 

    We now have even fancier drugs costing about $60,000 a year, about $5,000 a month, and they don’t even work very well; clinical remission at one year is only about 17 to 34 percent. And, instead of no adverse side effects, the drugs can give us a stroke, give us heart failure, and can even give us cancer, including a rare type of cancer that often results in death. Also, a serious brain disease known as progressive multifocal leukoencephalopathy, which can kill us, and for which there is no known treatment or cure. One drug lists an “increased risk of death” but touts that it’s just “a small pill” in an “easy-to-open bottle.” I’d skip the pills (and their potential side effects) and stick with plant-based eating.

    Doctor’s Note:

    If you missed the previous video, see Preventing Inflammatory Bowel Disease with Diet and stay tuned for The Best Diet for Crohn’s Disease Treatment, coming up next. 
     
    Check the related posts below for some older videos on IBD that may be of interest to you.

    Michael Greger M.D. FACLM

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  • Foods That Disrupt Our Microbiome | NutritionFacts.org

    Eating a diet filled with animal products can disrupt our microbiome faster than taking an antibiotic.

    If you search online for “Crohn’s disease and diet” or “ulcerative colitis and diet,” the top results are a hodgepodge of conflicting advice, as you can see below and at 0:15 in my video Preventing Inflammatory Bowel Disease with Diet. 

    What does science say? A systematic review of the medical literature on dietary intake and the risk of developing inflammatory bowel disease finds that Crohn’s disease is associated with the intake of fat and meat, whereas dietary fiber and fruits appear protective. The same associations are seen with ulcerative colitis, the other major inflammatory bowel disease—namely, increased risk with fat and meat, and a protective association with vegetable intake. 

    Why, according to this meta-analysis of nine separate studies, do meat consumers have about a 50 percent greater risk for inflammatory bowel disease? One possibility is that meat may be a vehicle for bacteria that play a role in the development of such diseases. For instance, meat contains “huge amounts of Yersinia.” It’s possible that antibiotic residues in the meat itself could be theoretically mucking with our microbiome, but Yersinia are so-called psychotropic bacteria, meaning they’re able to grow at refrigerator temperatures, and they’ve been found to be significantly associated with inflammatory bowel disease (IBD). This supports the concept that Yersinia infection may be a trigger of chronic IBD.

    Animal protein is associated with triple the risk of inflammatory bowel disease, but plant protein is not, as you can see below and at 1:39 in my video. Why? One reason is that animal protein can lead to the formation of toxic bacterial end products, such as hydrogen sulfide, the rotten egg gas. Hydrogen sulfide is not just “one of the main malodorous compounds in human flatus”; it is a “poison that has been implicated in ulcerative colitis.” So, if you go on a meat-heavy, low-carb diet, we aren’t talking just about some “malodorous rectal flatus,” but increased risk of irritable bowel syndrome, inflammatory bowel syndrome (ulcerative colitis), and eventually, colorectal cancer. 

    Hydrogen sulfide in the colon comes from sulfur-containing amino acids, like methionine, that are concentrated in animal proteins. There are also sulfites added as preservatives to some nonorganic wine and nonorganic dried fruit, but the sulfur-containing amino acids may be the more important of the two. When researchers gave people increasing quantities of meat, there was an exponential rise in fecal sulfides, as seen here and at 2:37 in my video. 

    Specific bacteria, like Biophilia wadsworthia, can take this sulfur that ends up in our colon and produce hydrogen sulfide. Eating a diet based on animal products, packed with meat, eggs, and dairy, can specifically increase the growth of this bacteria. People underestimate the dramatic effect diet can have on our gut bacteria. As shown below and at 3:12 in my video, when people are given a fecal transplant, it can take three days for their microbiome to shift. Take a powerful antibiotic like Cipro, and it can take a week. But if we start eating a diet heavy in meat and eggs, within a single day, our microbiome can change—and not for the better. The bad bacterial machinery that churns out hydrogen sulfide can more than double, and this is consistent with the thinking that “diet-induced changes to the gut microbiota [flora] may contribute to the development of inflammatory bowel disease.” In other words, the increase in sulfur compounds in the colon when we eat meat “is not only of interest in the field of flatology”—the study of human farts—“but may also be of importance in the pathogenesis of ulcerative colitis…” 

    Doctor’s Note:

    This is the first in a three-part video series. Stay tuned for The Best Diet for Ulcerative Colitis Treatment and The Best Diet for Crohn’s Disease Treatment. 

    Michael Greger M.D. FACLM

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  • What’s the Best Weight-Loss and Disease-Prevention Diet?  | NutritionFacts.org

    What’s the Best Weight-Loss and Disease-Prevention Diet?  | NutritionFacts.org

    The most effective diet for weight loss may also be the most healthful.

    Why are vegetarian diets so effective in preventing and treating diabetes? Maybe it is because of the weight loss. As I discuss in my video The Best Diet for Weight Loss and Disease Prevention, those eating more plant-based tend to be significantly slimmer. That isn’t based on looking at a cross-section of the population either. You can perform an interventional trial and put it to the test in a randomized, controlled community-based trial of a whole food, plant-based diet.

    “The key difference between this trial [of plant-based nutrition] and other approaches to weight loss was that participants were informed to eat the WFPB [whole food, plant-based] diet ad libitum and to focus efforts on diet, rather than increasing exercise.” Ad libitum means they could eat as much as they want; there was no calorie counting or portion control. They just ate. It was about improving the quality of the food rather than restricting the quantity of food. In the study, the researchers had participants focus just on a diet rather than exercising more exercise because they wanted to isolate the effects of eating more healthfully.

    So, what happened? At the start of the study, the participants were, on average, obese at nearly 210 pounds (95 kg) with an average height of about 5’5” (165 cm). Three months into the trial, they were down about 18 pounds (8 kg)—without portion restrictions and eating all the healthy foods they wanted. At six months in, they were closer to 26 pounds (12 kg) lighter. You know how these weight-loss trials usually go, though. However, this wasn’t an institutional study where the participants were locked up and fed. In this trial, no meals were provided. The researchers just informed them about the benefits of plant-based eating and encouraged them to eat that way on their own, with their own families, and in their own homes, in their own communities. What you typically see in these “free-living” studies is weight loss at six months, with the weight creeping back or even getting worse by the end of a year. But, in this study, the participants were able to maintain that weight loss all year, as you can see below and at 1:57 in my video.

    What’s more, their cholesterol got better, too, but the claim to fame is that they “achieved greater weight loss at 6 and 12 months than any other trial that does not limit energy [caloric] intake or mandate regular exercise.” That’s worth repeating. A whole food, plant-based diet achieved the greatest weight loss ever recorded at 6 and 12 months compared to any other such intervention published in the medical literature. Now, obviously, with very low-calorie starvation diets, you can drop down to any weight. “However, medically supervised liquid ‘meal replacements’ are not intended for ongoing use”—obviously, they’re just short-term fixes—“and are associated with ‘high costs, high attrition rates, and a high probability of regaining 50% or more of lost weight in 1 to 2 years.’” In contrast, the whole point of whole food, plant-based nutrition is to maximize long-term health and longevity.

    What about low-carb diets? “Studies on the effects of low-carbohydrate diets have shown higher rates of all-cause mortality”—meaning a shorter lifespan—“decreased peripheral flow-mediated dilation [artery function], worsening of coronary artery disease, and increased rates of constipation, headache, halitosis [bad breath], muscle cramps, general weakness, and rash.”

    The point of weight loss is not to fit into a smaller casket. A whole food, plant-based diet is more effective than low-carb diets for weight loss and has the bonus of having all good side effects, such as decreasing the risk of diabetes beyond just weight loss.

    “The lower risk of type 2 diabetes among vegetarians may be explained in part by improved weight status (i.e., lower BMI). However, the lower risk also may be explained by higher amounts of ingested dietary fiber and plant protein, the absence of meat- and egg-derived protein and heme iron, and a lower intake of saturated fat. Most studies report the lowest risk of type 2 diabetes among individuals who adhere to vegan diets. This may be explained by the fact that vegans, in contrast to ovo- and lacto-ovo-vegetarians, do not ingest eggs. Two separate meta-analyses linked egg consumption with a higher risk of type 2 diabetes.”

    Maybe it’s eating lower on the food chain, thereby avoiding the highest levels of persistent organic pollutants, like dioxins, PCBs, and DDT in animal products. Those have been implicated as a diabetes risk factor. Or maybe it has to do with the gut microbiome. With all that fiber in a plant-based diet, it’s no surprise there would be fewer disease-causing bugs and more protective gut flora, which can lead to less inflammation throughout the body that “may be the key feature linking the vegan gut microbiota with protective health effects”—including the metabolic dysfunction you can see in type 2 diabetes.

    The multiplicity of benefits from eating plant-based can help with compliance and family buy-in. “Whereas a household that includes people who do not have diabetes may be unlikely to enthusiastically follow a ‘diabetic diet,’ a low-fat plant-based approach is not disease-specific and has been shown to improve other chronic conditions. While the patient [with diabetes] will likely see improvement in A1C [blood sugar control], a spouse suffering from constipation or high blood pressure may also see improvements, as may children with weight issues,” if you make healthy eating a family affair.

    This is just a taste of my New York Times best-selling book, How Not to Diet. (As with all of my books, all proceeds I received went to charity.) Watch the book trailer. You may also be interested in its companion, The How Not to Diet Cookbook.

    Check out my hour-long Evidence-Based Weight Loss lecture for more. 

    Michael Greger M.D. FACLM

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  • Are Branched-Chain Amino Acids Good for Us?  | NutritionFacts.org

    Are Branched-Chain Amino Acids Good for Us?  | NutritionFacts.org

    I discuss why we may not want to exceed the recommended intake of protein.

    Diabetes isn’t just about the amount of body fat, but also the distribution of body fat. At 0:26 in my video Are BCAA (Branched-Chain Amino Acids) Healthy?, you can view cross-sections of thighs from two different patients using MRI. In the images, the fat shows up as white and the thigh muscle is black. At first glance, you might think the bottom cross-section has more fat since it’s ringed with more white. That is the subcutaneous fat, the fat under the skin. But, if you look at the top cross-section, you’ll see how the middle of the thigh muscle is more marbled with fat, like those really fatty Japanese beef steaks. That is the fat infiltrating into the muscle. In the graph below and at 0:48 in my video, the two cross sections are colored so you can see the different types of fat: the fat infiltrating the muscle in red, the fat between the muscles in green, and subcutaneous fat outside of the muscles and under the skin in yellow. If you add up all three types of fat, both of those thighs actually have the same amount of fat—just distributed differently.

    This seems to be the critical factor in terms of determining insulin resistance, the cause of type 2 diabetes. Researchers found that the subcutaneous adipose tissue, the fat right under the skin, was not associated with insulin resistance. Going back to the two cross sections, as seen below and at 1:20 in my video, it is healthier to have the bottom thigh with the thicker ring of subcutaneous fat but less fat infiltrating muscle than the top thigh with more fat present in the muscle.

    Is it possible a more plant-based diet also affects a more healthful distribution of fat?

    We now know the effect of a vegetarian diet versus a conventional diabetic diet on thigh fat distribution in patients with type 2 diabetes. Researchers took 74 people with diabetes and randomly assigned them to follow either a vegetarian diet or a conventional diabetic diet. Both diets were calorie-restricted by the same number of calories. The vegetarian diet was also egg-free, and dairy was limited to a maximum of one serving of low-fat yogurt a day. What did the researchers find? The reduction in the more benign subcutaneous fat was comparable; it was about the same in both groups. However, the more dangerous fat—the fat lodged inside the muscle itself—“was reduced only in response to a vegetarian diet.” So, even getting the same number of calories, there can be a healthier weight loss on a more plant-based diet.

    Those eating strictly plant-based also had lower levels of fat stuck inside the individual muscle fibers themselves, which may help explain why vegans in particular are often found to have the lowest odds of diabetes. It is not just because vegans are generally slimmer either. Even if you match subjects pound for pound, there is significantly less fat inside the muscle cells of vegans compared to omnivores. This is a good thing, since storing fat in muscle cells “may be one of the primary causes of insulin resistance,” which is what’s behind both prediabetes and type 2 diabetes. On the other hand, if you put someone on a high-fat diet, the fat in their muscle cells shoots up by 54 percent in just a single week.

    What about a high-protein diet? That may undermine one of the principal benefits of weight loss: eliminating the weight-loss-induced improvement in insulin resistance. Researchers put obese individuals on a calorie-restricted diet of less than 1,400 calories a day until they lost 10 percent of their body weight. Half of the participants were getting more of a regular protein intake (73 grams a day), and the other half were on a higher-protein diet (about 105 daily grams). Normally, if you lose 10 percent of your body weight, your insulin resistance improves. That’s why it is so critical for obese individuals with type 2 diabetes to lose weight. However, the beneficial effect of a 10 percent weight loss was eliminated by the high protein intake. Those extra 32 grams of protein a day abolished the weight-loss benefit. “The failure to improve…insulin sensitivity in the WL-HP [weight-loss high-protein] group is clinically important because it reflects a failure to improve a major pathophysiological [cause-and-effect] mechanism involved in the development of T2D,” type 2 diabetes. In summary, the researchers concluded that they demonstrated “the protein content of a weight loss diet can have profound effects on metabolic function.” 

    Is this true of any protein? As you can see below and at 4:19 in my video, if you split it between animal protein versus plant protein, following people over time, intake of animal protein is associated with an increased risk of diabetes in most studies.

    Intake of plant protein, however, appears to have either a neutral or even protective association with diabetes, as shown below and at 4:25 in my video. 

    Those were just observational studies, though. People who eat a lot of animal protein might have many unhealthy behaviors. However, you see the same thing in randomized, controlled, interventional trials, where you can improve blood sugar control just by replacing sources of animal protein with plant protein.

    We think it may be the branched-chain amino acids concentrated in animal protein. Higher levels in the bloodstream are associated with obesity and the development of insulin resistance. As you can see below and at 5:00 in my video, we may be able to drop our levels by sticking to plant proteins, but you don’t know if that has metabolic effects until you put it to the test. 

    Ruining the suspense, researchers titled their study: “Decreased Consumption of Branched-Chain Amino Acids Improves Metabolic Health.” They demonstrated that “a moderate reduction in total dietary protein or selected amino acids can rapidly improve metabolic health,” and this included improving blood sugar control, while also decreasing body mass index (BMI) and body fat. As you can see at 5:27 in my video, the protein-restricted group was eating hundreds more calories per day, significantly more calories than the control group, so they should have gained weight. But, no. They lost weight! After about a month and a half, they were eating more calories but lost more weight—about five more pounds than participants in the control group who were eating fewer calories, as you can see at 5:38 in my video. What’s more, this “protein restriction” had people eat the recommended amount of protein per day, about 56 daily grams. They should have been called the normal protein group or the recommended protein group instead, and the group eating more typically American protein levels and suffering because of it should have been called the excess protein group. Just sticking to the recommended protein intake doubled the levels of a pro-longevity hormone called FGF21, too, but we’ll save that for another discussion.

    To better understand the negative impact of omnivores getting too much protein relative to vegetarians, see my video Flashback Friday: Do Vegetarians Get Enough Protein?.

    I have several additional videos and blogs that may help explain some of the benefits of plant-based proteins. Check in the related posts below.

    Of course, the best way to treat type 2 diabetes is to get rid of it by treating the underlying cause, as described in my video How Not to Die from Diabetes. 

    Michael Greger M.D. FACLM

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  • Keto Diets and Diabetes  | NutritionFacts.org

    Keto Diets and Diabetes  | NutritionFacts.org

    Ketogenic diets are put to the test for diabetes reversal. 
     
    As you can see at the start of my video Does a Ketogenic Diet Help Diabetes or Make It Worse?, ketogenic diets can lower blood sugars better than conventional diets. So much so, in fact, that there is a keto product company that claims ketogenic diets can “reverse” diabetes. However, they are confusing the symptom (high blood sugars) with the disease (carbohydrate intolerance). People with diabetes can’t properly handle carbohydrates, and this manifests as high blood sugars. Clearly, if you stick to eating mostly fat, your blood sugars will stay low, but you may be actually making the underlying disease worse at the same time. 
     
    We’ve known for nearly a century that if you put people on a ketogenic diet, their carbohydrate intolerance can skyrocket within just two days. Below and at 0:46 in my video, you can see a graph from the study showing the blood sugar response two days after eating sugar. On a high-carb diet, blood sugar response is about 90 mg/dL. But, the blood sugar response to the same amount of sugar after a high-fat diet is about 190 mg/dL, nearly double. The intolerance to carbohydrates skyrocketed on a high-fat diet. 

    After one week on an 80 percent fat diet, you can quintuple your blood sugar spike in reaction to the same carb load compared to a week on a low-fat diet, as you can see in the graph below and at 1:12 in my video. 

    Even a single day of excessive dietary fat intake can do it, as you can see in the graph below and at 1:26 in my video. If you’re going in for a diabetes test, having a fatty dinner the night before can adversely affect your results. Just one meal high in saturated fat can make carbohydrate intolerance, the cause of diabetes, worse within four hours. 


    Given enough weight loss by any means, whether from cholera or bariatric surgery, type 2 diabetes can be reversed, but a keto diet for diabetes may not just be papering over the cracks, but actively throwing fuel on the fire. 
     
    I’ve been trying to think of a good metaphor. It’s easy to come up with things that just treat the symptoms without helping the underlying disease, like giving someone with pneumonia aspirin for their fever instead of antibiotics. However, a keto diet for diabetes is worse than that because it may treat the symptoms while actively worsening the disease. It may be more like curing the fever by throwing that pneumonia patient out into a snow bank or “curing” your amputated finger by amputating your hand. One of the co-founders of masteringdiabetes.org suggested it’s like a CEO who makes their bad bottom line look better by borrowing tons of cash. The outward numbers look better, but on the inside, the company is just digging itself into a bigger hole. 
     
    Do you remember The Club, that popular car anti-theft device that attaches to the steering wheel and locks it in place so the steering column can only turn a few inches? Imagine you’re in a car at the top of a hill with the steering wheel locked. Then, the car starts rolling down the hill. What do you do? Imagine there’s also something stuck under your brake pedal. The keto-diet equivalent response to this situation is who cares if you’re barreling down into traffic with a locked steering wheel and no brakes—just stick to really straight deserted roads without any stop signs or traffic lights. If you do that, problem solved! The longer you go, the more speed you’ll pick up. If you should hit a dietary bump in the road or start to veer off the path, the consequences could get more and more disastrous over time. However, if you stick to the keto straight and narrow, you’ll be a-okay! In contrast, the non-keto response would be to just unlock the steering wheel and dislodge whatever’s under your brake. In other words, fix the underlying problem instead of just whistling past—and then into—the graveyard. 
     
    The reason keto proponents claim they can “reverse” diabetes is they can successfully wean type 2 diabetics off their insulin. That’s like faith-healing someone out of the need for a wheelchair by making them stay in bed the rest of their life. No need for a wheelchair if you never move. Their carbohydrate intolerance isn’t gone. Their diabetes isn’t gone. In fact, it could be just as bad or even worse. Type 2 diabetes is reversed when you are weaned off insulin while eating a normal diet like everyone else. Then and only then do you not have diabetes anymore. A true diabetes reversal diet, as you can see below and at 4:58 in my video, is practically the opposite of a ketogenic diet: getting diabetics off their insulin within a matter of weeks by eating more than 300 grams of carbs a day! 
    The irony doesn’t stop there. One of the reasons people with diabetes suffer such nerve and artery damage is due to an inflammatory metabolic toxin known as methylglyoxal, which forms at high blood sugar levels. Methylglyoxal is the most potent creator of advanced glycation end products (AGEs), which are implicated in degenerative diseases—from Alzheimer’s and cataracts to kidney disease and strokes, as you can see below and at 5:31 in my video. 

    You get AGEs in your body from two sources: You can eat them preformed in your diet or make them internally from methylglyoxal if you have high blood sugar levels. On a keto diet, one would expect high exposure to preformed AGEs, since they’re found concentrated in animal-derived foods high in fat and protein, but we would expect less internal, new formation due to presumably low levels of methylglyoxal, given lower blood sugars from not eating carbs. Dartmouth researchers were surprised to find more methylglyoxal! As shown in the graph below and at 6:11 in my video, a few weeks on the Atkins diet led to a significant increase in methylglyoxal levels. Those in active ketosis did even worse, doubling the level of this glycotoxin in their bloodstream. 

    It turns out that high sugars may not be the only way to create this toxin, as you can see below and at 6:24 in my video. One of the ketones you make on a ketogenic diet is acetone (known for its starring role in nail polish remover). Acetone does more than just make keto dieters fail breathalyzer tests, “feel queasy and light-headed, and develop what’s been described as ‘rotten apple breath.’” Acetone can oxidize in the blood to form acetol, which may be a precursor for methylglyoxal.

    That may be why keto dieters can end up with levels of this glycotoxin as high as those with out-of-control diabetes, which can cause the nerve damage and blood vessel damage you see in diabetics. That’s another way keto dieters can end up with a heart attack. The irony of treating diabetes with a ketogenic diet may extend beyond just making the underlying diabetes worse, but by mimicking some of the disease’s dire consequences. 

    This is part of a seven-video series on keto, which you can find in related videos below.

    I also recently tackled diabetes.

    Michael Greger M.D. FACLM

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  • Muscle Shrinkage and Bone Loss on Keto Diets?  | NutritionFacts.org

    Muscle Shrinkage and Bone Loss on Keto Diets?  | NutritionFacts.org

    Ketogenic diets have been found to undermine exercise efforts and lead to muscle shrinkage and bone loss. 
     
    An official International Society of Sports Nutrition position paper covering keto diets notes the “ergolytic effect” of keto diets on both high- and low-intensity workouts. Ergolytic is the opposite of ergogenic. Ergogenic means performance-boosting, whereas ergolytic means performance-impairing. 
     
    For nonathletes, ketosis may also undermine exercise efforts. Ketosis was correlated with increased feelings of “perceived exercise effort” and “also significantly correlated to feelings of ‘fatigue’ and to ‘total mood disturbance,’” during physical activity. “Together, these data suggest that the ability and desire to maintain sustained exercise might be adversely impacted in individuals adhering to ketogenic diets for weight loss.” 
     
    You may recall that I’ve previously discussed that shrinkage of measured muscle mass among CrossFit trainees has been reported. So, a ketogenic diet may not just blunt the performance of endurance athletes, but their strength training as well. As I discuss in my video Keto Diets: Muscle Growth and Bone Density, study participants performed eight weeks of the battery of standard upper and lower body training protocols, like bench presses, pull-ups, squats, and deadlifts, and there was no surprise. You boost muscle mass—unless you’re on a keto diet, in which case there was no significant change in muscle mass after all that effort. Those randomized to a non-ketogenic diet added about three pounds of muscle mass, whereas the same amount of weight lifting on the keto diet tended to subtract muscle mass by about 3.5 ounces on average. How else could you do eight weeks of weight training and not gain a single ounce of muscle on a ketogenic diet? Even keto diet advocates call bodybuilding on a ketogenic diet an “oxymoron.” 
     
    What about bone loss? Sadly, bone fractures are one of the side effects that disproportionately plague children placed on ketogenic diets, along with slowed growth and kidney stones. Ketogenic diets may cause a steady rate of bone loss as measured in the spine, presumed to be because ketones are acidic, so keto diets can put people in what’s called a “chronic acidotic state.” 
     
    Some of the case reports of children on keto diets are truly heart-wrenching. One nine-year-old girl seemed to get it all, including osteoporosis, bone fractures, and kidney stones, then she got pancreatitis and died. Pancreatitis can be triggered by having too much fat in your blood. As you can see in the graph below and at 2:48 in my video, a single high-fat meal can cause a quintupling of the spike in triglycerides in your bloodstream within hours of consumption, which can put you at risk for inflammation of the pancreas.  

    The young girl had a rare genetic disorder called glucose transporter deficiency syndrome. She was born with a defect in ferrying blood sugar into her brain. That can result in daily seizures starting in infancy, but a ketogenic diet can be used as a way to sneak fuel into the brain, which makes a keto diet a godsend for the 1 in 90,000 families stricken with this disorder.

    As with anything in medicine, it’s all about risks versus benefits. As many as 30 percent of patients with epilepsy don’t respond to anti-seizure drugs. Unfortunately, the alternatives aren’t pretty and can include brain surgery that implants deep electrodes through the skull or even removes a lobe of your brain. This can obviously lead to serious side effects, but so can having seizures every day. If a ketogenic diet can help with seizures, the pros can far outweigh the cons. For those just choosing a diet to lose weight, though, the cost-benefit analysis would really seem to go the other way. Thankfully, you don’t need to mortgage your long-term health for short-term weight loss. We can get the best of both worlds by choosing a healthy diet, as I discussed in my video Flashback Friday: The Weight Loss Program That Got Better with Time.
     
    Remember the study that showed the weight loss was nearly identical in those who had been told to eat the low-carb Atkins diet for a year and those told to eat the low-fat Ornish diet, as seen below and at 4:18 in my video? The authors concluded, “This supports the practice of recommending any diet that a patient will adhere to in order to lose weight.” That seems like terrible advice. 

    There are regimens out there like “The Last Chance Diet which consisted of a low-calorie liquid formula made from leftover byproducts from a slaughterhouse [that] was linked to approximately 60 deaths from cardiovascular-related events.” An ensuing failed lawsuit from one widower laid the precedent for the First Amendment protection for those who produce deadly diet books. 

    It’s possible to construct a healthy low-carb diet or an unhealthy low-fat one—a diet of cotton candy would be zero fat—but the health effects of a typical low-carb ketogenic diet like Atkins are vastly different from a low-fat plant-based diet like Ornish’s. As you can see in the graph below and at 5:26 in my video, they would have diametrically opposed effects on cardiovascular risk factors in theory, based on the fiber, saturated fat, and cholesterol contents of their representative meal plans. 

    And when actually put to the test, low-carb diets were found to impair artery function. Over time, blood flow to the heart muscle itself is improved on an Ornish-style diet and diminished on a low-carb one, as shown below and at 5:44 in my video. Heart disease tends to progress on typical weight-loss diets and actively worsens on low-carb diets, but it may be reversed by an Ornish-style diet. Given that heart disease is the number one killer of men and women, “recommending any diet that a patient will adhere to in order to lose weight” seems irresponsible. Why not tell people to smoke? Cigarettes can cause weight loss, too, as can tuberculosis and a meth habit. The goal of weight loss is not to lighten the load for your pallbearers. 

     
    For more on keto diets, see my videos on the topic. Interested in enhancing athletic performance? Check out the related videos below. 

    Michael Greger M.D. FACLM

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  • The Safety of Keto Diets  | NutritionFacts.org

    The Safety of Keto Diets  | NutritionFacts.org

    What are the effects of ketogenic diets on nutrient sufficiency, gut flora, and heart disease risk? 

    Given the decades of experience using ketogenic diets to treat certain cases of pediatric epilepsy, a body of safety data has accumulated. Nutrient deficiencies would seem to be the obvious issue. Inadequate intake of 17 micronutrients, vitamins, and minerals has been documented in those on strict ketogenic diets, as you can see in the graph below and at 0:14 in my video Are Keto Diets Safe?. 

    Dieting is a particularly important time to make sure you’re meeting all of your essential nutrient requirements, since you may be taking in less food. Ketogenic diets tend to be so nutritionally vacuous that one assessment estimated that you’d have to eat more than 37,000 calories a day to get a sufficient daily intake of all essential vitamins and minerals, as you can see in the graph below and at 0:39 in my video. 


    That is one of the advantages of more plant-based approaches. As the editor-in-chief of the Journal of the American Dietetic Association put it, “What could be more nutrient-dense than a vegetarian diet?” Choosing a healthy diet may be easier than eating more than 37,000 daily calories, which is like putting 50 sticks of butter in your morning coffee. 
     
    We aren’t just talking about not reaching your daily allowances either. Children have gotten scurvy on ketogenic diets, and some have even died from selenium deficiency, which can cause sudden cardiac death. The vitamin and mineral deficiencies can be solved with supplements, but what about the paucity of prebiotics, the dozens of types of fiber, and resistant starches found concentrated in whole grains and beans that you’d miss out on? 
     
    Not surprisingly, constipation is very common on keto diets. As I’ve reviewed before, starving our microbial self of prebiotics can have a whole array of negative consequences. Ketogenic diets have been shown to “reduce the species richness and diversity of intestinal microbiota,” our gut flora. Microbiome changes can be detected within 24 hours of switching to a high-fat, low-fiber diet. A lack of fiber starves our good gut bacteria. We used to think that dietary fat itself was nearly all absorbed in the small intestine, but based on studies using radioactive tracers, we now know that about 7 percent of the saturated fat in a fat-rich meal can make it down to the colon. This may result in “detrimental changes” in our gut microbiome, as well as weight gain, increased leaky gut, and pro-inflammatory changes. For example, there may be a drop in beneficial Bifidobacteria and a decrease in overall short-chain fatty acid production, both of which would be expected to increase the risk of gastrointestinal disorders. 
     
    Striking at the heart of the matter, what might all of that saturated fat be doing to our heart? If you look at low-carbohydrate diets and all-cause mortality, those who eat lower-carb diets suffer “a significantly higher risk of all-cause mortality,” meaning they live, on average, significantly shorter lives. However, from a heart-disease perspective, it matters if it’s animal fat or plant fat. Based on the famous Harvard cohorts, eating more of an animal-based, low-carb diet was associated with higher death rates from cardiovascular disease and a 50 percent higher risk of dying from a heart attack or stroke, but no such association was found for lower-carb diets based on plant sources.  
     
    And it wasn’t just Harvard. Other researchers have also found that “low-carbohydrate dietary patterns favoring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favored plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain bread, were associated with lower mortality…” 
     
    Cholesterol production in the body is directly correlated to body weight, as you can see in the graph below and at 3:50 in my video. 

    Every pound of weight loss by nearly any means is associated with about a one-point drop in cholesterol levels in the blood. But if we put people on very-low-carb ketogenic diets, the beneficial effect on LDL bad cholesterol is blunted or even completely neutralized. Counterbalancing changes in LDL or HDL (what we used to think of as good cholesterol) are not considered sufficient to offset this risk. You don’t have to wait until cholesterol builds up in your arteries to have adverse effects either; within three hours of eating a meal high in saturated fat, you can see a significant impairment of artery function. Even with a dozen pounds of weight loss, artery function worsens on a ketogenic diet instead of getting better, which appears to be the case with low-carb diets in general.  

    For more on keto diets, check out my video series here. 

    And, to learn more about your microbiome, see the related videos below.

    Michael Greger M.D. FACLM

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  • Can You Sustain Weight Loss on Ketosis?  | NutritionFacts.org

    Can You Sustain Weight Loss on Ketosis?  | NutritionFacts.org

    Might the appetite-suppressing effects of ketosis improve dietary compliance? 

    The new data are said to debunk “some, if not all, of the popular claims made for extreme carbohydrate restriction,” but what about ketones suppressing hunger? In a tightly controlled metabolic ward study where the ketogenic diet made things worse, everyone ate the same number of calories, but those on a keto diet lost less body fat. But, out in the real world, all of those ketones might spoil your appetite enough that you’d end up eating significantly less overall. On a low-carb diet, people end up storing 300 more calories of fat every day. Outside of the laboratory, though, if you were in a state of ketosis, might you be able to offset that if you were able to sustainably eat significantly less? 
     
    Paradoxically, as I discuss in my video Is Weight Loss on Ketosis Sustainable?, people may experience less hunger on a total fast compared to an extremely low-calorie diet. This may be thanks to ketones. In this state of ketosis, when you have high levels of ketones in your bloodstream, your hunger is dampened. How do we know it’s the ketones? If you inject ketones straight into people’s veins, even those who are not fasting lose their appetite, sometimes even to the point of getting nauseated and vomiting. So, ketones can explain why you might feel hungrier after a few days on a low-calorie diet than on a total zero-calorie diet—that is, a fast. 
     
    Can we then exploit the appetite-suppressing effects of ketosis by eating a ketogenic diet? If you ate so few carbs to sustain brain function, couldn’t you trick your body into thinking you’re fasting and get your liver to start pumping out ketones? Yes, but is it safe? Is it effective? 
     
    As you can see below and at 1:58 in my video, a meta-analysis of 48 randomized trials of various branded diets found that those advised to eat low-carb diets and those told to eat low-fat ones lost nearly identical amounts of weight after a year.

    Obviously, high attrition rates and poor dietary adherence complicate comparisons of efficacy. The study participants weren’t actually put on those diets; they were just told to eat in those ways. Nevertheless, you can see how even just moving in each respective direction can get rid of a lot of CRAP (which is Jeff Novick’s acronym for Calorie-Rich And Processed foods). After all, as you can see in the graph below and at 2:37 in my video, the four largest calorie contributors in the American diet are refined grains, added fats, meat, and added sugars. 

    Low-carb diets cut down on refined grains and added sugars, and low-fat diets tend to cut down on added fats and meat, so they both tell people to cut down on donuts. Any diet that does that already has a leg up. I figure a don’t-eat-anything-that-starts-with-the-letter-D diet could also successfully cause weight loss if it caused people to cut down on donuts, danishes, and Doritos, even if it makes no nutritional sense to exclude something like dill. 

    The secret to long-term weight-loss success on any diet is compliance. Diet adherence is difficult, though, because any time you try to cut calories, your body ramps up your appetite to try to compensate. This is why traditional weight-loss approaches, like portion control, tend to fail. For long-term success, measured not in weeks or months but in years and decades, this day-to-day hunger problem must be overcome. On a wholesome plant-based diet, this can be accomplished thanks in part to calorie density because you’re just eating so much food. On a ketogenic diet, it may be accomplished with ketosis. In a systematic review and meta-analysis entitled “Do Ketogenic Diets Really Suppress Appetite,” researchers found that the answer was yes. Ketogenic diets also offer the unique advantage of being able to track dietary compliance in real-time with ketone test strips you can pee on to see if you’re still in ketosis. There’s no pee stick that will tell you if you’re eating enough fruits and veggies. All you have is the bathroom scale. 

    Keto compliance may be more in theory than practice, though. Even in studies where ketogenic diets are being used to control seizures, dietary compliance may drop below 50 percent after a few months. This can be tragic for those with intractable epilepsy, but for everyone else, the difficulty in sticking long-term to ketogenic diets may actually be a lifesaver. I’ll talk about keto diet safety next. 

    The keto diet is in contrast to a diet that would actually be healthful to stick to. See, for example, my video series on the CHIP program here. 
     
    This was the fourth video in a seven-part series on keto diets. If you haven’t yet, be sure to watch the others listed in the related videos below. 

    Michael Greger M.D. FACLM

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  • Can You Lose Weight on a Keto Diet?  | NutritionFacts.org

    Can You Lose Weight on a Keto Diet?  | NutritionFacts.org

    Let’s dive into ketogenic diets and their $33-billion gimmick. 

    The carbohydrate–insulin model of obesity, the underlying theory that ketogenic diets have some sort of metabolic advantage, has been experimentally falsified. Keto diet proponents’ own studies showed the exact opposite: Ketogenic diets actually put you at a metabolic disadvantage and slow the loss of body fat. How much does fat loss slow down on a low-carb diet?  

    As I discuss in my video Keto Diet Results for Weight Loss, if you cut about 800 calories of carbohydrates from your diet a day, you lose 53 grams of body fat a day. But if you cut the same number of fat calories, you lose 89 grams of fat a day. Same number of calories cut, but nine butter pats’ worth of extra fat melting off your body each day on a low-fat diet, compared to a low-carb one. Same number of calories, but about 80 percent more fat loss when you cut down on fat instead of carbs. You can see a graph of these results below and at 1:07 in my video. The title of the study speaks for itself: “Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss Than Carbohydrate Restriction in People with Obesity.” 

    Just looking at the bathroom scale, though, would mislead you into thinking the opposite. After six days on the low-carb diet, study subjects lost four pounds. On the low-fat diet, they lost less than three pounds, as you can see in the graph below and at 1:40 in my video. So, according to the scale, it looked like the low-carb diet wins hands down. You can see why low-carb diets are so popular. What was happening inside their bodies, however, tells the real story. The low-carb group was losing mostly lean mass—water and protein. This loss of water weight helps explain why low-carb diets have “been such a persistent theme for authors of diet books and such ‘cash cows’ for publishers,” going back more than the last 150 years. That’s their secret. As one weight-loss expert noted, “Rapid water loss is the $33-billion diet gimmick.” 

    When you eat carbohydrates, your body bulks up your muscles with glycogen for quick energy. Eat a high-carbohydrate diet for three days, and you may add about three pounds of muscle mass onto your arms and legs, as you can see below and at 2:34 in my video. Those glycogen stores drain away on a low-carb diet and pull water out with it. (The ketones also need to be flushed out of the kidneys, pulling out even more water.) On the scale, that can manifest as four more pounds coming off within ten days, but that “was all accounted for by losses in total body water”—that is water loss. 

    The bottom line: Keto diets just don’t hold water. 

    The thrill of seeing the pounds come off so quickly on the scale keeps many coming back to the low-carb altar. When the diet fails, the dieters often blame themselves, but the intoxication of that initial, rapid weight loss may tempt them back, like getting drunk again after forgetting how terrible the last hangover was. This has been dubbed the “false hope syndrome.” “The diet industry thrives for two reasons—big promises and repeat customers,” something low-carb diets were built for, given that initial, rapid water loss. 

    What we care about is body fat. In six days, the low-fat diet extracted a total of 80 percent more fat from the body than the low-carb diet. It’s not just one study either. As you can see below and at 3:54 in my video, you can look at all of the controlled feeding trials where researchers compared low-carb diets to low-fat ones, swapping the same number of carb calories for fat calories or vice versa. If a calorie is just a calorie, then all of the studies should have crossed that zero line in the middle, straddling “favors low-fat diet” and “favors low-carb diet,” and indeed six did. One study showed more fat loss on a low-carb diet, but every other study favored the low-fat diet—more loss of body fat eating the same number of calories. When you put all of the studies together, we’re talking 16 more grams of daily body fat lost on the low-fat diets. That’s like four more pats of butter melting off your body on a daily basis. Less fat in the mouth means less fat on the hips, even when you’re taking in the same number of calories. 

    This is the third installment of my seven-part series on keto diets. 

    This keto research came from the deep dive I took for my book How Not to Diet. (All proceeds I receive from my books are donated to charity.) You can learn more about How Not to Diet and order it here. Also please feel free to check out some of my popular weight-loss videos in related videos below. 

    Michael Greger M.D. FACLM

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  • Testing the Keto Diet Theory  | NutritionFacts.org

    Testing the Keto Diet Theory  | NutritionFacts.org

    Do low-carb and ketogenic diets have a metabolic advantage for weight loss? 

    When you don’t eat enough carbohydrates, you force your body to burn more fat. “However, this rise in fat oxidation [burning] is often misconstrued as a greater rate of net FM [fat-mass] reduction” in the body, ignoring the fact that, on a ketogenic diet, your fat intake shoots up, too. What happens to your overall body fat balance? You can’t empty a tub by widening the drain if you’re opening the faucet at the same time. Low-carb advocates had a theory, though, the “carbohydrate–insulin model of obesity,” which I discuss in my video Keto Diet Theory Put to the Test.  

    Proponents of low-carb diets, whether a ketogenic diet or a more relaxed form of carbohydrate restriction, suggested that decreased insulin secretion would lead to less fat storage, so even if you were eating more fat, less of it would stick to your frame. We’d burn more and store less, the perfect combination for fat loss—or so the theory went. To their credit, instead of just speculating about it, they decided to put it to the test. 

    Gary Taubes formed the Nutrition Science Initiative (NuSI) to sponsor research to validate the carbohydrate–insulin model. He’s the journalist who wrote the controversial 2002 New York Times Magazine article “What If It’s All Been a Big Fat Lie?” which attempted to turn nutrition dogma on its head by arguing in favor of the Atkins diet with its bunless bacon cheeseburgers based on the carbohydrate–insulin model. (Much of Nina Teicholz’s book The Big Fat Surprise is simply recycled from Taubes’ earlier work.)  

    In response, some of the very researchers Taubes cited to support his thesis accused him of twisting their words. One said, “The article was incredibly misleading…I was horrified.” Said another, “He took this weird little idea and blew it up, and people believed him…What a disaster.” It doesn’t matter what people say, though. All that matters is the science. 

    Taubes attracted $40 million in committed funding for his Nutrition Science Initiative to prove to the world that you could lose more body fat on a ketogenic diet. NuSI contracted noted researcher Kevin Hall from the National Institutes of Health to perform the study. Seventeen overweight or obese men were effectively locked in what’s called a metabolic ward for two months to allow researchers total control over their diets. For the first month, they were placed on a typical high-carbohydrate diet (50 percent carbs, 35 percent fat, 15 percent protein), then were switched to a low-carb ketogenic diet (only 5 percent of calories from carbohydrates and 80 percent fat) for the second month. Both diets had the same number of daily calories. So, if a calorie is a calorie when it comes to weight loss, there should be no difference in body fat loss on the regular diet versus the ketogenic diet. If Taubes was right, though, if fat calories were somehow less fattening, then body fat loss would become accelerated on a keto diet. Instead, in the very study funded by the Nutrition Science Initiative, researchers found that body fat loss slowed during the ketogenic diet. 

    Why do people think the keto diet works if it actually slows fat loss? Well, as you can see in the graph below and at 3:40 in my video, if you looked only at the readings on bathroom scales, the ketogenic diet would seem like a smashing success. Participants went from losing less than a pound a week on the regular diet during the first two weeks of the study to losing three and a half pounds within seven days after switching to the ketogenic diet. What was happening inside their bodies, however, told a totally different story: Their rate of body fat loss was slowed by more than half. So, most of what they were losing was just water weight. It’s presumed the reason they started burning less fat on a ketogenic diet was because, without the preferred fuel of carbohydrates, their bodies started burning more of their own protein—and that’s exactly what happened. Switching to a ketogenic diet made them lose less fat mass and more fat-free mass. Indeed, they lost more lean mass. That may help explain why the leg muscles of CrossFit trainees placed on a ketogenic diet may shrink as much as 8 percent. The vast lateralis, the biggest quad muscle in your leg, shrunk in thickness by 8 percent on a ketogenic diet. 

    Yes, the study subjects started burning more fat on the ketogenic diet, but they were also eating so much more fat on the keto diet that they ended up retaining more fat in their body, despite the lower insulin levels. This is “diametrically opposite” to what the keto crowd predicted, and this is from the guy Nutrition Science Initiative paid to support its theory. In science-speak, “the carbohydrate–insulin model failed experimental interrogation.” 

    In light of this “experimental falsification” of the low-carb theory, the Nutrition Science Initiative effectively collapsed but, based on its tax returns, not before Taubes and his co-founder personally pocketed millions of dollars in compensation. 

    This is the second installment in my seven-part series on keto diets. In case you missed them, check out the other related videos below.  

    The more things change, the more they stay the same. I created a whole website about the Atkins Diet, but, sadly, people keep falling into the low-carb trap. You can find some of my older videos on low-carb diets listed below. 

    Michael Greger M.D. FACLM

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  • Keto Diet to Effectively Fight Cancer?  | NutritionFacts.org

    Keto Diet to Effectively Fight Cancer?  | NutritionFacts.org

    What does the science say about the clinical use of ketogenic diets for epilepsy and cancer? 

    Blood sugar, also known as blood glucose, is the universal go-to fuel for the cells throughout our bodies. Our brain burns through a quarter pound of sugar a day because “glucose is the preferred metabolic fuel.” We can break down proteins and make glucose from scratch, but most comes from our diet in the form of sugars and starches. If we stop eating carbohydrates (or stop eating altogether), most of our cells switch over to burning fat. Fat has difficulty getting through the blood-brain barrier, though, and our brain has a constant, massive need for fuel. Just that one organ accounts for up to half of our energy needs. Without it, the lights go out…permanently. 

    To make that much sugar from scratch, our body would need to break down about half a pound of protein a day. That means we’d cannibalize ourselves to death within two weeks, but people can fast for months. What’s going on? The answer to the puzzle was discovered in 1967. Harvard researchers famously stuck catheters into the brains of obese subjects who had been fasting for more than a month and discovered that ketones had replaced glucose as the preferred fuel for the brain. Our liver can turn fat into ketones, which can then breach the blood-brain barrier and sustain our brain if we aren’t getting enough carbohydrates. Switching fuels has such an effect on brain activity that it has been used to treat epilepsy since antiquity. 

    In fact, the prescription of fasting for the treatment of epileptic seizures dates back to Hippocrates. In the Bible, even Jesus seems to have concurred. To this day, it’s unclear why switching from blood sugar to ketones as a primary fuel source has such a dampening effect on brain overactivity. How long can one fast? To prolong the fasting therapy, in 1921, a distinguished physician scientist at the Mayo Clinic suggested trying what he called “ketogenic diets,” high-fat diets designed to be so deficient in carbohydrates that they could effectively mimic the fasting state. “Remarkable improvement” was noted the first time it was put to the test, efficacy that was later confirmed in randomized, controlled trials. Ketogenic diets started to fall out of favor in 1938 with the discovery of the anti-seizure drug that would become known as Dilantin, but they’re still being used today as a third- or fourth-line treatment for drug-refractory epilepsy in children. 

    Oddly, the success of ketogenic diets against pediatric epilepsy seems to get conflated by “keto diet” proponents into suggesting a ketogenic diet is beneficial for everyone. Know what else sometimes works for intractable epilepsy? Brain surgery, but I don’t hear people clamoring to get their skulls sawed open. Since when do medical therapies translate into healthy lifestyle choices? Scrambling brain activity with electroshock therapy can be helpful in some cases of major depression, so should we get out the electrodes? Ketogenic diets are also being tested to see if they can slow the growth of certain brain tumors. Even if they work, you know what else can help slow cancer growth? Chemotherapy. So why go keto when you can just go chemo? 

    Promoters of ketogenic diets for cancer are paid by so-called ketone technology companies that offer to send you salted caramel bone broth powder for a hundred bucks a pound or companies that market ketogenic meals and report “extraordinary” anecdotal responses in some cancer patients. But more concrete evidence is simply lacking, and even the theoretical underpinnings may be questionable. A common refrain is that “cancer feeds on sugar.” But all cells feed on sugar. Advocating ketogenic diets for cancer is like saying Hitler breathed air so we should boycott oxygen. 

    Cancer can feed on ketones, too. Ketones have been found to fuel human breast cancer growth and drive metastases in an experimental model, more than doubling tumor growth. Some have even speculated that this may be why breast cancer often metastasizes to the liver, the main site of ketone production. As you can see below and at 4:59 in my video Is Keto an Effective Cancer-Fighting Diet?, if you drip ketones directly onto breast cancer cells in a petri dish, the genes that get turned on and off make for much more aggressive cancer, associated with significantly lower five-year survival in breast cancer patients, as you can see in the following graph and at 5:05 in my video. Researchers are even considering designing ketone-blocking drugs to prevent further cancer growth by halting ketone production.  

    Let’s also think about what eating a ketogenic diet might entail. High animal fat intake may increase the mortality risk among breast cancer survivors and potentially play a role in the development of breast cancer in the first place through oxidative stress, hormone disruption, or inflammation. This applies to men, too. “A strong association” has been found “between saturated fat intake and prostate cancer progression and survival.” Those in the top third of consumption of these kinds of fat-rich animal foods appeared to triple their risk of dying from prostate cancer. This isn’t necessarily fat in general either. No difference has been found in breast cancer death rates based on total fat intake. However saturated fat intake specifically may negatively impact breast cancer survival, increasing the risk of dying from it by 50 percent. There’s a reason the official American Cancer Society and American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline recommend a dietary pattern for breast cancer patients that’s essentially the opposite of a ketogenic diet. It calls for a diet that’s “high in vegetables, fruits, whole grains, and legumes [beans, split peas, chickpeas, and lentils]; low in saturated fats; and limited in alcohol consumption.” 

    “To date, not a single clinical study has shown a measurable benefit from a ketogenic diet in any human cancer.” There are currently at least a dozen trials underway, however, and the hope is that at least some cancer types will respond. Still, even then, that wouldn’t serve as a basis for recommending ketogenic diets for the general population any more than recommending everyone get radiation, surgery, and chemo just for kicks. 

    “Keto” has been the most-searched keyword on NutritionFacts.org for months, and I didn’t have much specific to offer…until now. Check out my other videos on the topic in related videos below. 

     For an overview of my cancer work, watch How Not to Die from Cancer. 

    Michael Greger M.D. FACLM

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