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What Is the Ketogenic Diet and How Does It Compare to the 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.

Summary

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.{{cta('cd305230-6e34-42f6-9e2c-c2beda556f50')}}References:

  1. Foster GD, Wyatt HR, Hill JO, Makris AP, Rosenbaum DL, Brill C, Stein RI, Mohammed BS, Miller B, Rader DJ, Zemel B, Wadden TA, Tenhave T, Newcomb CW, and Klein S. “Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial.” Ann Intern Med 2010 153:147-57
  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.

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062524---Keto-Blog

Ketogenic Diets and Aging

Chances are, you or someone you know has tried the keto diet at some point in time. This high-fat, very low-carbohydrate eating plan appeals to many due to its promise of rapid weight loss. In this blog, Dr. Sears explores some of the latest scientific findings on ketogenic diets and provides caution before hopping on this trend. What is a Ketogenic Diet? The ketogenic diet is a high-fat, very low-carbohydrate eating plan. This significant reduction in carbohydrates to induce a metabolic state is called ketosis. This only occurs when there is not enough carbohydrates in your liver to completely convert fatty acids to carbon dioxide and water. The normal conversion generates the chemical energy (ATP) that keeps us alive. In the absence of ketosis, each fatty acid generates 108 molecules of ATP when oxidized in the mitochondria. Ketone bodies make less ATP when they are metabolized by mitochondria. How much less? About five times less. This is like switching the gasoline in your car from high-octane fuel to low octane fuel as ketone bodies increase in the blood. Furthermore, contrary to popular belief, ketones are not an ideal energy source for the brain, as glucose remains the preferred fuel for ATP production in brain cells. Lack of blood glucose is a highly stressful situation for the brain. This is why the body secretes the stress hormone cortisol from the adrenal glands during ketosis to breakdown protein and convert the amino acids into glucose for the brain. This explains why even under complete starvation for 38 days, the blood glucose levels never dropped below 68 mg/dL. This is still considered as a normal blood sugar level. Where did this blood glucose come from if there was none in the diet for 38 days? The answer is neo-glucogenesis primarily using lean body mass. Ketogenic Diets Pros and Cons Interest in ketogenic diets rises and falls about every 20 years. They’re very low-carbohydrate diets that claim that carbohydrates make you fat and keep you fat. This is simply not true. It is not carbohydrates per se but a disrupted metabolism that makes you fat. To be more specific, it is the inhibition of AMPK, the master regulator of your metabolism that makes you fat. Why? As AMPK activity increases, you burn stored fat faster. Frankly, I’ve always been amazed by the re-emergence of ketogenic diets. Eighteen years ago, I published the premier clinical study demonstrating that, under equal calorie intake in which all the food was provided to the subjects for six weeks, the Zone Diet was better than a ketogenic diet in reducing total weight, excess body fat, and inflammation. Now, a recent study revealed some more very concerning findings about the long-term effects of ketogenic diets. This new study indicated that following a keto diet causes a rise in senescent cells, popularly known as “zombie cells.” Zombie Cells are damaged cells that no longer divide but don't die. That’s bad enough, but zombie cells continue spreading inflammation throughout the body. As the number of zombie cells increases in your body, they become a living nightmare. Why? Zombie cells accelerate aging because they cause the earlier development of many chronic diseases. In this study they found that zombie cells in the animals began to appear while they were on a ketogenic diet. The zombie cells then disappeared when researchers changed the diet to a “non-ketogenic diet” (i.e., the Zone diet). And when the animals were given a Keto diet again, the zombie cells reappeared. Notice a trend? If you want to hear more about this study you can listen to our recent podcast at Dr.Sears.com. Based on earlier blogs, this adds to the list of downsides for following a ketogenic diet versus the Zone Diet. PROS Rapid initial weight loss: This is primarily due to the loss of retained water from the glycogen stores in the liver, which is rapidly used up to maintain blood sugar levels. Since these glycogen stores in the liver contain significant levels of retained water, much of the initial weight loss is water rather than stored body fat. If your main goal is loss retained water, this can be seen as a benefit. Of course, going to a sauna would also work. Reduced hunger: Ketogenic diets are rich in protein. Any increase in protein intake can help reduce hunger. CONS Production of acetone: One of the ketone bodies produced during ketosis is acetone, which is also the main chemical in nail polish. Increased calcium loss: A ketogenic diet can lead to higher calcium loss from bones. Limited fat utilization: High levels of dietary fat reduce the likelihood of using stored body fat for energy unless you also significantly restrict calories. Reduced energy levels: The lack of ATP production on a ketogenic diet can lead to easier fatigue during mild exercise. Damage from cheat meals: After seven days on a keto diet, a single high-carb cheat meal can damage blood vessels. Lack of polyphenols: This makes it difficult to activate genes that optimize metabolism by improving mitochondrial efficiency in converting fat into ATP. No long-term weight loss advantage: Long-term studies show no difference in weight loss between a ketogenic diet and a low-fat, high-carb diet. No short-term metabolic advantage: Careful studies demonstrate that fat loss on a ketogenic diet is the same as on a low-fat, high-carb diet with the same caloric intake. Compromised gut health: A lack of fermentable fiber from carbohydrates can lead to poor gut health and an increased risk of developing a leaky gut, which can cause significant inflammation. Furthermore, short-chain fatty acids (SCFA) are the metabolic product of fermentable fiber. These SCFA are powerful epigenetic signaling agents that enhance gene transcription. Ketosis generates a different type of hydroxylated short fatty acid (3-hydroxyl butyrate, that has no effect on gene transcription. In addition, the lack of SCFA has significant negative consequences on the gut-brain axis. Cortisol build-up: To produce glucose for the brain, cortisol levels increase to breakdown protein to make sufficient glucose via neoglucogenesis. Excess cortisol can lead to insulin resistance that cause regain of some of initially loss body fat. In addition, increased cortisol levels cause a depressed immune system as well as destruction of memory cells in the hippocampus. The initial benefits of following the ketogenic diet result in some initial weight loss (primarily water weight rather than fat loss), long-term studies show no significant differences in overall weight loss. Now new findings show a ketogenic diet may lead to significant adverse health consequences by accelerating the formation of zombie cells. Call me crazy, but I feel the key to longevity and wellness comes down to better metabolic control instead of living in a constant state of ketosis. Following Metabolic Engineering® for a lifetime provides that pathway of losing body fat without ketosis. References 1. 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. 2. 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. 3. Sung-Jen Wei, Joseph R Schell, E Sandra Chocron, Mahboubeh Varmazyad, Guogang Xu, Wan Hsi Chen, Gloria M Martinez, Felix F Dong, Prethish Sreenivas, Rolando Trevino Jr , Haiyan Jiang, Yan Du, Afaf Saliba, Wei Qian, Brandon Lorenzana, Alia Nazarullah, Jenny Chang, Kumar Sharma, Erin Munkácsy, Nobuo Horikoshi, David Gius. Ketogenic diet induces p53-dependent cellular senescence in multiple organs. Sci Adv. 2024 May 17;10(20):eado1463. doi: 10.1126/sciadv.ado1463. 4. Owen OE, Felig P, Morgan AP, Wahren J, Cahill GF Jr. Liver and kidney metabolism during prolonged starvation. J Clin Invest. 1969 Mar;48(3):574-83. doi: 10.1172/JCI106016. 5. Chriett, S., Dąbek, A., Wojtala, M. et al. Prominent action of butyrate over β-hydroxybutyrate as histone deacetylase inhibitor, transcriptional modulator and anti-inflammatory molecule. Sci Rep 9, 742 (2019). https://doi.org/10.1038/s41598-018-36941-9. 6. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020 Jan 31;11:25. doi: 10.3389/fendo.2020.00025. 

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050824---Tofu-Blog

Tofu: Tips and Recipes Ideas

I have been eating tofu for a very long time, much longer than the 30 or so years I have been following the Zone Diet. Back then many of my favorite recipes came from the Tassajara cookbooks by Edward Espe Brown, the celebrated chef from the kitchen at California’s famous Zen Mountain Center, and cookbooks by Louise Hagler, a.k.a. Wendy Louise, a well-known authority on vegetarian cooking who is associated with a community in Tennessee known as The Farm. Those books are still among the best resources for tofu recipes. My mantra has always been if you don’t like something, don’t eat it. Keep this in mind if you’re new to tofu, start slowly by combining it with flavors and foods you like.    Tips and Suggestions    Firm-sprouted tofu is my preference for the Zone Diet. Unlike traditional tofu, which contains significant amounts of both protein and carbohydrate, sprouted has almost no carbohydrates. It’s lighter tasting, refreshing, and very filling.   Freezing tofu results in a chewy, sponge-like texture. I don’t recommend freezing, but some people prefer it when using tofu to substitute for meat in a recipe.    Baked tofu comes in a variety of flavors and makes an excellent quick meal with some vegetables and fruit added. It’s also great in salads.     Tofu made it into the book “The Top 100 Zone Foods” by Barry Sears.    Some recipes call for draining the tofu first. I find that usually isn’t necessary.   Tofu takes on the flavor of whatever is added to it.    Add nutritional yeast flakes to give a cheesy flavor to vegan tofu scrambles and dips. It’s also rich in protein and vitamin B12.   Cherry Vanilla Tofu “Ice Cream”   Tip: This doesn’t freeze or store well, so prepare only the amount you plan to serve immediately.   Using an immersion blender or a food processor blend equal parts of frozen dark cherries and firm tofu, plus some vanilla extract (preferably alcohol-free for best flavor). Serve immediately.  Tofu Scramble  This is great for breakfast, lunch, or dinner, and we’ve even brought it on long day hikes for a snack.   Crumble some firm tofu and stir in a generous amount of seasonings, taking care not to overdo it with the salt. Heat in a well-seasoned or nonstick skillet with a little Zone-friendly oil to the desired doneness.    Optional: If time allows, sauté some chopped onion in the skillet before adding the tofu and seasonings.    My favorite seasoning combination for this dish at my house is onion powder, garlic powder, turmeric, paprika, some oregano or thyme, nutritional yeast flakes, salt, and ground black pepper. The yellow color of the turmeric makes it somewhat like scrambled eggs.   Tofu Veggie Almond Pasta Salad   Dressing: Thin some smooth almond butter by stirring in some water, a little vinegar, and either soy sauce or Bragg’s Liquid Aminos (an unfermented soy sauce found in the health food section of most grocery stores).    Toss together cooked Dr. Sears’ Zone PastaRx Fusilli, tofu cut into cubes, matchstick cut red bell pepper, chopped green parts of scallions (a.k.a. green onions), and the almond butter dressing. Serve immediately or chill to serve later. It will keep well in the fridge for two or three days.   Use your imagination and see what you can come up with.  Experiment and have fun with it. Try using tofu to make cheesecakes, whipped desserts, tofu chocolate pudding, tofu “cream” based soups, tofu pot pie (think chicken pot pie), tofu burgers, tofu burritos, Buffalo tofu (like Buffalo wings), layered Mediterranean dips, tofu “meatballs”, grilled tofu, and more.    Enjoy! 

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