What Is the Ketogenic Diet and How Does It Compare to the Zone Diet?

Ketogenic Diet vs Zone Diet

Over the past few months we’ve received a number of inquiries regarding Dr. Sears’ stance on the Ketogenic Diet and how it relates to the Zone in terms of health and weight loss. Is this just the next diet craze or is it as good for weight loss and health as it’s touted to be?

What Is the Ketogenic Diet?

The ketogenic diet is a high-fat, low carbohydrate diet consisting of approximately 75% fat, 20% protein and 5% carbohydrate. Compare this to the Zone which is moderate in these macronutrients and supplies 30% fat, 30% protein and 40% carbohydrate as total dietary calories.

The Ketogenic Diet is based on getting the body into a state of ketosis (hence “keto”). Ketosis is a back-up metabolic system used to provide the brain with an energy source, called ketones, if glucose isn’t available or if blood levels fall too low.

What’s the Buzz About?

The popularity in the Ketogenic Diet stems from the quick weight loss it produces and its perceived health benefits. The diet is thought to increase the body’s ability to burn stored body fat and lower insulin levels. It’s important to note that the weight loss that stems from this diet isn’t necessarily fat loss, despite fat being the preferred/primary fuel on this eating plan.

Weight Loss from the Ketogenic Is Not From Stored Body Fat

In general, when we lose weight, it results from one of three factors: the loss of retained water, loss of muscle mass or loss of stored body fat. The ideal scenario would be to lose stored body fat.

Ketogenic diets can promote an initial loss of retained water that comes with the depletion of glycogen (storage form of glucose). This is because stored glycogen retains significant levels of water. As the glycogen levels are reduced (due to limited carbohydrates in the diet), the retained water associated with that stored glycogen is also rapidly lost through increased urination.

Although the loss of weight on a scale can be considerable in the first few days of a ketogenic diet, it will result in little loss of stored body fat. The loss of stored body fat only comes with significant calorie restriction as the body has many biological processes that help us to preserve it.

Why You Don’t Lose Fat on the Ketogenic Diet

Ketogenic diets are high in fat, which means the blood levels of fat will also be increased. As the availability of glucose in the blood decreases and the availability of fat increases, the metabolic flexibility (inherent in muscle cells) switches to using circulating fat as the preferred source of fuel for energy production (a.k.a. ATP), instead of glucose. This leads to the misconception that by getting into a state of ketosis you burn stored body fat. Instead, it is that the higher levels of dietary fat entering the blood stream are now becoming the preferred source of energy.

Furthermore, a ketogenic diet being low in carbohydrates lowers insulin levels so less of that circulating fat can be stored in adipose tissue for long-term storage. Protein can also increase insulin levels resulting in circulating fat being transported into the adipose tissue for storage. This is why eating a high-fat diet containing excess calories, but with adequate levels of protein would not result in any fat loss, even though the carbohydrate content of such a diet can be very low.

Hormonal and Physiological Changes that Take Place on Long-term Ketogenic Diets

What is known from clinical studies is that significant hormonal changes take place on ketogenic diets and it’s not necessarily for the better. Here is a snap shot of the hormones impacted when following the diet long-term.

Hormonal Changes

Increase Insulin1 IncreaseThyroid 2
IncreaseCortisol 2 DecreaseTestosterone 3,4

Physiological Changes

DecreaseImmune Function 5 IncreaseMental and Physical Fatigue Due to Low Blood Sugar 6
IncreaseGut Dysbiosis 7,8
Since the ketogenic diet is limited in carbohydrates, it will not supply enough fermentable fiber for gut health. This lack of fermentable fiber will reduce the production of short-chain fatty acids (SCFA) that are required for maintaining the integrity of the mucus barrier and tight junction of the mucosa as well as increasing the production of T-regulatory cells. The end result is a greater likelihood of metabolic endotoxemia which can lead to weight regain.
IncreaseLoss of Muscle Mass 9
Stimulation of protein synthesis requires the combination of insulin (to drive amino acids into the muscle cell) and testosterone (to activate the receptors that signal for the stimulation of new muscle formation. Both hormones are decreased in ketogenic diets thus making it difficult to maintain muscle mass.

Why the Zone Diet Is Preferable to the Ketogenic Diet

A few years back, we set out to test how the Zone Diet compared to a Ketogenic Diet. This study kept both the protein and total calorie intake constant between a ketogenic diet and the non-ketogenic Zone Diet10. It controlled the diet for the first six weeks by supplying all the food to the subjects. These were calorie restricted diets (1,500 calories per day) to ensure that there was a sufficient calorie deficit to determine the effect of the two diets on loss of stored body fat, which can be only be achieved if a calorie deficient is maintained for long enough period of time.

In the first three weeks of the study, the weight loss of the non-ketogenic Zone Diet and the ketogenic were essentially the same. However, in the second three-week period, the weight loss on the non-ketogenic Zone diet was greater than compared to the ketogenic diet. The same was true for fat loss. Even though it was a calorie restricted diet, there was no change in the fat-free (i.e. muscle mass) mass of either group during the six-week period indicating that the protein intake (which was equal in both diets) was sufficient to spare the loss of muscle mass.

The AA/EPA ratio in the blood is indicative of inflammation. On the ketogenic diet, this inflammatory marker doubled during the six-week period of the study, whereas there was slight lowering on the non-ketogenic Zone Diet. Furthermore, mental state and exercise capacity of the subjects following the non-ketogenic Zone Diet improved during the study when compared to the subjects following the ketogenic diet.

This study presented evidence that there were no advantages of a ketogenic diet compared to one with equal protein, calories, and higher carbohydrate and lower fat content such as the Zone Diet. In addition, the study suggested that a ketogenic diet significantly increases inflammation in a relatively short period of time compared to non-ketogenic Zone Diet.


Although initial weight loss (but not necessarily fat loss) on a ketogenic diet may be higher compared to a non-ketogenic diet, there are no long-term differences in overall weight loss. This may be due to the changes in hormonal responses induced by a ketogenic diet. Furthermore, the hormonal and inflammatory changes induced by a ketogenic diet may have significant adverse health consequences as suggested in epidemiological studies.

Fat loss is only achieved by calorie restriction and can be maintained only if the diet used is one that is without hunger or fatigue so that the fat loss can be maintained for a lifetime. This can be achieved by a calorie-restricted diet that is adequate in protein to prevent the loss of lean muscle mass, supplies adequate levels of carbohydrates to reduce the generation of ketone bodies and promote gut health, maintains adequate levels of blood glucose for the brain, and finally contains a low level of dietary fat to encourage the use of stored fat for energy by the rest of the body. That’s the promise of the Zone Diet.

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  2. Ebbeling CB, Swain JF, Feldman HA, Wong WW, Hachey DL, Garcia-Lago E, and Ludwig DS. “Effects of dietary composition on energy expenditure during weight-loss maintenance.” JAMA 2012 307:2627-2634
  3. Anderson KE, Rosner W, Khan MS, New MI, Pang SY, Wissel PS, and Kappas A. “Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man.” Life Sci. 1987 40:1761-1788.
  4. Lane AR, Duke JW, and Hackney AC. “Influence of dietary carbohydrate intake on the free testosterone: cortisol ratio responses to short-term intensive exercise training.” Eur J Appl Physiol 2010 108:1125-1131.
  5. Sephton SE, Dhabhar FS, Keuroghlian AS, Giese-Davis J, McEwen BS, Ionan AC, and Spiegel D. “Depression, cortisol, and suppressed cell-mediated immunity in metastatic breast cancer.” Brain Behav Immun 2009 23:1148-1155.
  6. White AM, Johnston CS, Swan PD, Tjonn SL, and Sears B. “Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study.” J Am Diet Assoc. 2007 107:1792-1796.
  7. Duncan SH, Belenguer A, Holtrop G, Johnstone AM, Flint HJ, and Lobley GE. “Reduced dietary intake of carbohydrates by obese subjects results in decreased concentrations of butyrate and butyrate-producing bacteria in feces.” Appl Environ Microbiol 2007 73:1073-1078.
  8. Cani PD, Amar J, Iglesias MA, Poggi M, Knauf C, Bastelica D, Neyrinck AM, Fava F, Tuohy KM, Chabo C, Waget A, Delmée E, Cousin B, Sulpice T, Chamontin B, Ferrières J, Tanti JF, Gibson GR, Casteilla L, Delzenne NM, Alessi MC, and Burcelin R. “Metabolic endotoxemia initiates obesity and insulin resistance.” Diabetes. 2007 56:1761-1772.
  9. Fujita S, Rasmussen BB, Cadenas JG, Grady JJ, and Volpi E. “Effect of insulin on human skeletal muscle protein synthesis is modulated by insulin-induced changes in muscle blood flow and amino acid availability.” Am J Physiol Endocrinol Metab 2006 291: E745–E754.
  10. Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 2006 83:1055-61.


About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 45 years to the study of lipids. He has published 40 scientific articles and holds 14 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 14 books, including the New York Times #1 best-seller, The Zone, which have sold more than 6 million copies in the U.S. and have been translated into 22 different languages.


  1. Ana

    Dr. Sears all my admiration and respect to you!!! I did keto for long time but I try to start the zone diet but my body now can work properly with carbs. I did Keto and works amazing but my gut is very painful with all that fat and when I used fiber my gut doesn’ts works properly. What I can do to do The Zone diet without gaining weight after many years of Keto? I think that many people have this same question. It’s possible to change in the zone the macro radio % maybe less carbs? Thank you

  2. George Henderson (@puddleg)

    You seem, by favouring isocaloric diet trials, and focussing on the straw man of metabolic advantage (which isn’t mentioned or measured in most ketogenic diet studies and is irrelevant to most intended outcomes) to be ignoring the satiating effects of ketosis and the advantage of reduced energy intake without hunger.
    You say that the insulin response to protein in the keto diet will make you store fat. But why wouldn’t that make the Zone diet, higher in protein, more fattening? Easy to say it’s not when a test is isocaloric and short term. In fact, the glucagon response to protein balances the insulin response when it comes to fat storage, because protein isn’t eaten to supply fat, but to supply amino acids for protein synthesis, with excess supplying glucose and ketone bodies rather than fat.
    The omega 6/3 HUFA ratio rises on a keto diet because of a lower rate of conversion of AA to prostaglandins, hence the antinociceptive effect of this diet.
    “Increased 20:4n-6 and the ratios of 20:4n-6/20:5n-3 and n-6/n-3 are commonly viewed as pro-inflammatory, but unexpectedly were consistently inversely associated with responses in inflammatory proteins. In summary, a very low carbohydrate diet resulted in profound alterations in fatty acid composition and reduced inflammation compared to a low fat diet.”
    There are many other ketogenic diet studies than the few you cite, which opens you to the allegation that these are are cherry picked to make the Zone look good, and the trending rival keto look bad, rather than informing a more nuanced discussion about why the ketogenic diet does work.

    • Barry Sears

      Please notice that I spoke of doing trials that are not only isocaloric, but also with equivalent amounts of protein. The satiety comes from the protein levels, not from ketosis. This was pointed out in a recent review (Hall (Eur J Clin Nutr 71:323-326 (2017)). The “metabolic advantage” of a ketogenic diet compared to a isocaloric, but lower protein diet is simply due to the increased thermogenesis of protein (Johnston et al J Am Coll Nutr 21:55-61 (2002). The only study that I am aware of that has compared a ketogenic diet isocaloric diet and with similar levels of protein to the Zone Diet was (Johnston et al. Am J Clin Nutr 83:1055-1061 (2006)). The variable in that study was the ratio of carbohydrate and fat in the two diets. The ketogenic diet demonstrated no metabolic advantage to the Zone Diet.

      My statement about ketogenic diets and insulin is that their long-term use increases cortisol levels (Ebbling et al. JAMA 307:2627-2634 (2012)). Increases in cortisol generates increased insulin resistance that leads to weight gain.

      Finally, a recent study (Schaller et al. J Clin Lipidol doi:10.1016/j.jacl.2017.06.011) has demonstrated the reduction of the AA/EPA ratio is highly correlated with the reduction in all-cause mortality over a 15-year period. Extensive data from Japan on cardiovascular patients come to the same conclusions.

      I knew Robert Atkins personally, and always liked him. That’s why I gave a televised eulogy for him on CBS Morning News shortly after his death. Nonetheless, I eagerly await any published study that demonstrates that an isocaloric ketogenic diet with equivalent levels of dietary protein is superior to the Zone Diet.

  3. cliff hansen

    Why would you publish this with the blatant contradiction about insulin so close? You write, “a ketogenic diet being low in carbohydrates lowers insulin levels” then immediately follow that with a graph showing that insulin increases on the diet.

    I am also curious of your thoughts on the A to Z diet study showing that of the Atkins (similar to keto), LEARN, Ornish and Zone diets, the Atkins performed the best and the Zone performed the worst.


    • Barry Sears

      In the short-term, a ketogenic diet will lower insulin levels. But my table your refer to was based on long-term use of a ketogenic diets. If subjects on ketogenic diet lose more weight early in a study, but regain that lost weight relative to those subjects following a high-carbohydrate diet, then this strongly suggests that long-term insulin levels are rising on a ketogenic diet. I also refer you to a review by Hall (Eur J Clin Nutr 71:323-326 (2017) that challenges some of the basic assumptions often made about ketogenic diets.

      It is known from animal models that early fat loss from the adipose tissue and reduction of insulin levels on a ketogenic diet are accompanied by increases in liver fat accumulation (Jornayvaz et al Am J Physiol Endcrionol Metabol 299: E808-815 and Garbow et al Am J Physiol Gastrointest Liver Physiol 300: G957-G967(2011)). A more recent review on this subject can be found in the May 2017 issue of Nutrients (Kosinski and Jornayvaz Nutrients 19:E517(2017)).

      Finally there is a major difference between weight loss and fat loss especially when the subjects in trial are not adequately controlled as in the A to Z study. When the Zone Diet was directly compared to the Atkins diet under controlled isocaloric and iso-protein conditions, it was found that the Zone Diet had greater weight loss and greater fat loss compared to the Atkins diet (Johnston et al Am J Clin Nutr 83:1055-1061 (2006)). The only parameter in which the Atkins diet was superior to the Zone Diet was a dramatic increase in inflammation as measured by the AA/EPA ratio in only six weeks.

  4. John

    Personally i eat ketogenic diet for some time. Health is very important for me 🙂
    Nice post, Thanks for sharing.

    • Barry Sears

      It is not the diet that counts, but the metabolic results the come from following it. Reaching the Zone means reaching a metabolic state in the body where inflammation is optimally managed. This requires being the appropriate ranges of the three clinical markers (AA/EPA ratio, TG/HDL ratio, and HbA1c) that define the the Zone. That’s the top of the mountain. There are many potential paths to get there. Although I believe the Zone Diet is easiest and most clinically validated dietary pathway to reach that goal, not everyone is genetically the same. Finding the right dietary pathway for yourself and sticking with it is best way for living a longer and better life.

  5. Don Sharpe

    Dr. Sears, I have benefited from your research and your fish oil. I also use your AA/EPA ratio test and have a score of under 3. I modified your research in my personal results however by not eating soy products of any kind in spite of your promotion of it as a good source of protein and I also eat mostly organic fruits and veges as I believe that the quality of our food is of way more importance than you seem to give it. Yes, the Zone Diet works in its claims whether one chooses or has no choice but to eat conventionally grown toxic GMO food with all of the pesticides, herbicides etc,, but common sense tells us this causes grave consequences to our health and longevity. I really sense that you seem to be defending your product/brand too much, and not giving credit where it is due in all of the very positive research on the ketogenic diet. I hope you will consider many of the very valid comments that Nick Mavrick made, and that you will consider doing more research, especially in regards to the quality of the nutrients we put in our bodies. It sounds like Nick has much respect for you, as I do, in your past research but I also know that it can be hard to admit when you are wrong about certain things or at least having a somewhat biased view when you have profited so much for a long time now without having to modify your model. I think you need to act quickly to maintain your following and credibility. We need you to be a leader in more research concerning the ketogenic diet, in lieu of posturing to condemn it. I thank you so much for the impact that you have had on the quality of my life with what I learned from your research. I am forever grateful. Your friend, Don Sharpe

    • Barry Sears

      Ultimately all diets have to analyzed in direct competition under controlled conditions. This means the competing diets must be isocaloric and contain equal levels of protein to minimize thermogenic effects of protein. This means you can then alter the ratio of fat to carbohydrate to determine which ratio provides the best metabolic outcome. To my knowledge the only published studies in this regard is my study in the American Journal of Clinical Nutrition (Johnston et al AJCN 83:1055) that demonstrated no advantage of the ketogenic diet versus the Zone Diet and our analysis of the effects of these diets on exercise fatigue (White et al J Am Diet Assoc 107:1792 (2007).

      The only way to lose excess body fat (very different than losing weight) is through calorie-restriction. Such a calorie-restricted diet should be protein-adequate to prevent a negative nitrogen balance coupled with adequate carbohydrates to provide adequate blood glucose to prevent the need for additional neo-glucogenesis mediated by increased cortisol production that breaks down muscle mass into glucose as well as adequate fermentable fiber and polyphenols for maintain gut health and an appropriate omega-6 to omega-3 fatty acids and minimal levels of pro-inflammatory palmitic acid to maintain an adequate balance of the initiation and resolution phases of the inflammatory process. A tall order meaning a lot more careful clinical research is still required.

      Two studies that are worth reading are Hall et al. “Energy expenditure and body composition changes after an isocaloric ketogenic diet in overweight and obese men.” AJCN 104: 324 (2016) and Hall “A review of the carbohydrate-insulin model of obesity.” Eur J Clin Nutr 71:323 (2017) to see the complexity of the problem.

      • Jennifer L. Warren, MD

        Thank you Dr. Sears! As a what certified family medicine physician, and board-certified Obesity Medicine physician who has practiced medical weight management exclusively for the past 13 years, I have found your research incredibly valuable, and have seen the positive health results born out in my clinical practice. I have seen crazy fad diets come and go over the years, and I appreciate a researcher like you who can stay above the fray, focus on the science, and help clear the air and promote health for so many people. My friend Dr. Melina Jampolis, is, as you know, another incredible supporter of your work!

  6. David Craig

    So, What about those of us, like myself, whom have been doing the ketogenic diet for a long time, have lost a significant amount of weight, 295 pounds, and have increased the amount of muscle mass that I have, bench has increase from 135lbs to 315. It seems that your observation would be inaccurate.

    • Barry Sears

      You should be congradulated for your excellence results. However, the reason you do clinical research to ask questions about larger number of individuals under controlled circumstances. I published such an article in the American Journal of Clinical Nutrition comparing the Zone Diet to the Atkins diet under such conditions. The only area that the Atkins diet was superior to the Zone Diet was increasing inflammation.

  7. Barry Sears

    There are three things that drive tumor biology; elevated blood glucose, inflammation, and the activation of the gene transcription factor mTOR. You want to maintain the HbA1c in the range sufficient for brain function, but not to stimulate tumor growth. However, as demonstrated in 2006 in the American Journal of Clinical Nutrition, a ketogenic diet increases inflammation. It was also demonstrated by Harvard in 2012 that a ketogenic diet increases cortisol that further depresses the immune system. Not a good idea for treating cancer. Finally, reducing mTOR activity requires reducing leucine intake or increasing AMP kinase activity that can be stimulated by polyphenols. The Zone Diet is a calorie-restricted diet that controls the hormones that drive tumor biology. It would be my diet of choice if I developed cancer.

    • Jennifer L. Warren, MD

      That is very concerning, to hear that leucine could promote oncogenesis, particularly since high-leucine protein sources have been promoted in recent years as a method of bodybuilding, and as a method of preserving muscle loss in perimenopausal in postmenopausal women during weight loss. How do you feel about the use of daily whey protein? My understanding was that it may actually have an anti-cancer effect, and may actually offset a possibly cancer- promoting affect of cassein.

  8. Barry Sears

    There are three things that drive tumor biology; elevated blood glucose, inflammation, and the activation of the gene transcription factor mTOR. You want to maintain the HbA1c in the range sufficient for brain function, but not to stimulate tumor growth. However, as demonstrated in 2006 in the American Journal of Clinical Nutrition, a ketogenic diet increases inflammation. It was also demonstrated by Harvard in 2012 that a ketogenic diet increases cortisol that further depresses the immune system. Not a good idea for treating cancer. Finally, reducing mTOR activity requires reducing leucine intake or increasing AMP kinase activity that can be stimulated by polyphenols. The Zone Diet is a calorie-restricted diet that controls the hormones that drive tumor biology. It would be my diet of choice if I developed cancer.

  9. Barry Sears

    There are three things that drive tumor biology; elevated blood glucose, inflammation, and the gene transcription factor mTOR. You want to maintain the HbA1c in the range sufficient for brain function, but not to stimulate tumor growth. However, as demonstrated in 2006 in the American Journal of Clinical Nutrition, a ketogenic diet increases inflammation. It was also demonstrated by Harvard in 2012 that a ketogenic diet increase cortisol that further depresses the immune system. Reducing mTOR activity requires reducing leucine intake. The Zone Diet is a calorie-restricted diet that controls the hormones that drive tumor biology.

    • Barry Sears

      Bad math by the graphic artist coupled with poor editing on my part. I will correct it shortly.

  10. Nick Mavrick

    This is nonsense.
    First of all, this isn’t a new fad. This diet has been around for almost 100 years and has a remarkable history of therapeutic success.
    B-hydroxybuterate (the main ketone body produced in the liver) is protein-sparing (so…muscle sparing) so weight loss after the initial loss of glycogen and then the water loss that is associated with cooling inflammation, the loss of weight is fat.
    The claims about mental and physical fatigue are ridiculous. 70-75% of your brain runs quite smoothly on a steady diet of ketone bodies, the other 25-30% uses glucose supplied by the roughly 200 calories/day of carbohydrate OR creates the necessary amount through gluconeogenesis.
    Carbohydrate is a NON-ESSENTIAL nutrient. We can make it.
    A sugar-burner has about 1,600-2,000 calories at his/her disposal during long exertion while a fat-adapted athlete has 60,000-100,000. On top of that, there is less lactate produced in a keto-adapted athlete so perceived and actual fatigue take longer to set in. 100% of the studies on athletes that showed a minor loss in endurance and power were done on athletes who were less than 2 weeks keto-adapted. There is some loss during the adaptation phase, mostly because of electrolyte imbalances caused by an sudden and drastic change in the signals between insulin and aldosterone. The kidneys start to dump sodium precipitously and the athlete goes into “keto flu” (formerly, “Atkins Flu”). Taking a multi-mineral in the morning, drinking a teaspoon of sea salt in about 6 oz of water (with a tbsp of MCT oil, if you like) before your workout should be sufficient, and then a normal dose of magnesium before bed should set you straight.
    And why on earth would insulin go up? The aldosterone picture is predicated upon LOW insulin.
    Lower insulin means lower cortisol as there is NEVER an instance of reactive hypoglycemia.
    Testosterone goes up almost across the board, for one reason, because the cortisol picture changes and there is less chance of pregnenalone being stolen for the cortisol pathway and it goes into the androstenedione cycle instead. what’s more, you are giving yourself more of the building blocks for sex hormones when you eat more fat
    Cholesterol levels DO go up in most, but the RATIOS improve and we all know at this point that JUST LDL is a pretty unreliable marker for CVD risk. LDL goes up: but which type? The type that is one of the body’s most powerful antioxidants? The type that is associated with higher testosterone? Or the deleterious small dense LDL which only cause problems when they lodge in damaged endothelial tissue and oxidize? Few Docs are measuring that, so your guess is as good as mine. Also HDL goes up. Nobody mentions that. “Good cholesterol” for those of you who still believe in those misleading labels. Also-and most importantly-triglycerides go down. Triglycerides are made in the liver out of…you guessed it…carbohydrates for storage.
    Fiber CAN be an issue for some, but those are not the people who are getting their 50 or so grams of NET carbs from fibrous veggies.
    1 cup broccoli, 1 cup spinach, 1/2 c blackberries, 1/4 c walnuts, 2 tbsp chia seeds, 1/2 avocado, 8 spears asparagus, 1 c chopped green bell pepper=21 grams net carbohydrate, 28 grams fiber. You still have 29 grams of carbs to go. How is that not enough fiber? The average American gets something like 12 grams. You could double these carb numbers and still have wiggle room…with almost 60 grams of fiber….soooo…I’m pretty sure that the microbiome is also quite manageable under this diet.
    Also, you can eat cultured veggies which are both pre- and pro-biotic. Problem solved.
    It’s fine to like your diet over other diets, but saying things about it that are clearly slanted damages your own credibility.

    • Barry Sears

      I suggest you read the references in my blog. In addition, I published a study in the American Journal of Clinical Nutrition in 2006 that was a carefully controlled study comparing the Zone Diet to the Atkins diet demonstrating no benefits of the Atkins diet other than doubling in the levels of inflammation as measured by the AA/EPA ratio.

      • Nick Mavrick

        I will, Doc.
        It is very important to note that I have never advocated an Atkins Diet. While Dr. Atkins was certainly onto something, the artificially-generated fat-phobia that was at its peak during the height of his work made achieving true ketosis unlikely for many if not most of his followers.
        In the presence of excessive protein, it is difficult to get very deep into nutritional ketosis because of gluconeogenesis, so many of the proposed benefits are never achieved. Gluconeogenesis=insulin exposure; insulin exposure=reduced fat oxidation and reduced ketone production.
        Also, Doctor Sears, I think that you will agree that published studies and how their results are presented are often to be believed with a grain of salt.
        Obviously arachodonic acid elevation is no laughing matter, but how did you control for that? (I apologize for responding prior to reading the study that you reference) Was the quality or source of the proteins or fats taken into consideration? were the participants receiving a large proportion of those fats from plant-based highly-polyunsaturated oils? Because that will ruin your Omega ratio (as you know, there is ZERO Omega-3 in plant fats, though 2-4% of the ALA is converted in a healthy body to EPA/DHA). What were the protein sources? Were they from game meats, wild-caught fish, grass-fed ruminant animals, pastured chickens living their evolutionarily-appropriate lives? These are vital factors.
        If this is the only metric by which Zone Diet outperformed Atkins (which, AGAIN, I never advocated), I don’t think that it’s a very strong argument.
        While I do recommend to folks that they consume lots of nuts and seeds (the fatty acid profiles or which are obviously Omega-6 dominated), I also advise that they off-set that with EPA/DHA supplementation.
        Problem solved….in theory.

        • Mike McCloskey

          For the sake of accuracy, rather than to take sides in Keto vs. Zone, the claim that “as you know, there is ZERO Omega-3 in plant fats” is false. The alpha-linolenic acid (ALA) to which N.M. refers obviously is an omega-3 fatty acid. The claim that “2-4% of the ALA is converted in a healthy body to EPA/DHA” also is oversimplified to the point of being misleading. Inefficient, yes, but there are large differences between sexes (much higher in ‘healthy young females’ than ‘healthy young males’), genetic differences between ‘healthy’ individuals, retroconversion of DHA to EPA, etc.

          • Barry Sears

            I have never said there is no omega-3 fatty acids in plants, but I have stated there is no EPA and DHA in plants unless you genetically alter the plants.

        • Barry Sears

          You control for elevated arachidonic acid by decrease insulin (that stimulates delta 5-desaturase that converts DGLA into AA), increase EPA intake (that inhibits the same enzyme), or dramatically reduce your intake of linoleic acid. Ideally, you do all three simultaneously.

          As Dr. David Ludwig of Harvard Medical School said in a recent article in the Washington Post, “nutrition is wickedly difficult”.

    • Denis Sullivan

      Where are your references, Nick? Sounds more like your opinion and your final words would appear apt to apply to your comments.

      • Nick Mavrick

        I’m only halfway through this paper, but here are the references so far.

        3. Clark, Nancy. Stored Glucose and Glycogen.” Sports Nutrition Guidebook (3rd Edition)
        4. Volek, Jeff, and Stephen D. Phinney. The Art and Science of Low Carbohydrate Performance: A Revolutionary Program to Extend Your Physical and Mental Performance Envelope. Lexington, KY: Beyond Obesity, 2012. Print.
        5. Veldhorst, Margriet AB, Margriet D. Westerterp-Plantenga, and Klaas R. Westerterp. “Gluconeogenesis and energy expenditure after a high protein carbohydrate free diet.” American Journal of Nutrition 90.3 (2009): 519-26. Web.
        6. Ward, Colin. Ketone body metabolism [internet]. 2015 Nov 18; Diapedia 51040851169 rev. no. 29. Available from: https://doi.org/10.14496/dia.51040851169.29
        7. Hendon, Louise. “What are the Optimum Ketone Levels for a Ketogenic Diet?” Paleo Magazine 1 Nov. 2016: n. pag. Print.
        8. Veech, Richard L. “The therapeutic implications of ketone bodies: the effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism.” Prostaglandins, Leukotrienes and Essential Fatty Acids 70.3 (2004): 309-19. Web.
        9. “Insulin and Its Metabolic Effects.” Mercola.com. N.p., n.d. Web. 09 June 2017.
        10. Stafstrom, Carl Ernest., Jong M. Rho, and James W. Wheless. Epilepsy and the ketogenic diet. Totowa, NJ: Humana Press, 2010. Print.
        11. “Dateline .” Dateline. NBC. New York, New York, 24 Oct. 1994. Television.
        12. Moore, Jimmy, and Eric C. Westman. Keto clarity: your definitive guide to the benefits of a low-carb, high-fat diet. Las Vegas: Victory Belt Publishing, Inc., 2014. Print..

        • Tim G

          The sound of crickets here is overwhelming. I guess nobody has anything to say…

        • Barry Sears

          I don’t think a segment on Dateline is a particularly strong reference. I again refer to my published article that directly compares the Zone Diet to a ketogenic diet under isocaloric conditions with equal amounts of protein varying only the ratio of carbohydrate to fat between the two diets.

  11. John Sochacki

    How does eating 30% protein on the Zone Diet stimulate glucagon? It seems that glucagon is activated when blood sugar drops and the signal goes out to the pancreas to inject glucagon to increase blood sugar in the blood for use.

    • Barry Sears

      A 400 calorie meal containing 30% protein would contain 30 grams of protein. It was demonstrated by Harvard Medical School (Ludwig et al Pediatrics 1-3:e26) in 1999 that in obese children consuming the 30% protein meal containing 400 calories stimulated glucagon, whereas lower levels (15 grams) at the same calorie content depressed glucagon levels. It is the levels of the amino acids that enter the blood that stimulate the alpha cells in the pancreas to release glucagon, whereas glucose stimulates the beta cells to release insulin. You need a balance to stabilize blood glucose levels.

      • Jennifer L. Warren, MD

        Fascinating! I have noticed over the last 10 years that when I have increased my patients breakfast protein from 15 g to 30 g, they have improved satiety and improved weight loss. Wonder if this is related to the glucagon effect in some way?
        I have also had a patient with type 1 diabetes who had been told by the Joslin clinic to incease her insulin dose to cover for elevated glucose after consuming a high-protein meal – I assume that is from the glucagon effect.

        • BJ

          “Wonder if this is related to the glucagon effect in some way?”

          Have you ever bothered to read any of Dr. Sears’ books??? Or even just his blog posts? He’s already answered this question many times. And you claim to be an MD?

  12. Hakan Birke

    Very interesting. I have personally eaten a ketogenic diet for some time. It seems however that my blood glucose levels are elevated. Do you have any explanation?

    • Barry Sears

      It may be due to increase cortisol secretion that would cause insulin resistance.

  13. Ted Hillison

    Very interesting. One comment I would make about the ketone if diet is that for people who
    Have cancer this diet provides a way to essentially starve the cancer cells from their food source….glucose. I believe for that type of patient the ketgenic diet can provide more health wbwnecots based on specific need. I’m interested though in how the inflammatory issues may interact with cancer patients

    • Barry Sears

      There are three things that drive tumor biology; elevated blood glucose, inflammation, and the activation of the gene transcription factor mTOR. You want to maintain the HbA1c in the range sufficient for brain function, but not to stimulate tumor growth. However, as I demonstrated in 2006 in the American Journal of Clinical Nutrition, a ketogenic diet increases inflammation. It was also demonstrated by Harvard in 2012 that a ketogenic diet increases cortisol that further depresses the immune system. Not a good idea for treating cancer. Finally, reducing mTOR activity requires reducing leucine intake or increasing AMP kinase activity that can be stimulated by polyphenols. The Zone Diet is a calorie-restricted diet that controls the hormones that drive tumor biology. It would be my diet of choice if I developed cancer.


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