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Tag: Ketones

  • 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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