All Recipes All Zone Living Articles
zone_calorie-restricted_diet-online-1

Then & Now: Calorie Restriction and the Impact on Disease

 Reduce your risk of chronic disease by making simple changes to your diet. Starting with Hippocrates 2,500 years ago, to Luigi Carnaro 400 years ago, to Dr. Barry Sears today, data continues to prove that a calorie restricted diet can reduce your risk of chronic disease. Discover how you can benefit from history repeating itself.

More than 400 years ago, Luigi Cornaro demonstrated that calorie restriction increases your health span. The story began in the year 1507, when Cornaro, a Venetian nobleman, was near death at age 40 due to a poor dietary lifestyle. At that point, he started a rigorous calorie-restriction program. Starting at age 83, Cornaro wrote three widely-read diet books. When Cornaro died at age 99, his death was due simply to old age, not from any chronic disease.

Calorie Restriction is Not Malnutrition

Calorie restriction is not the same as starvation. It usually consists of a 30% reduction in normal caloric intake without sacrificing any nutrition. A recent study set out to validate the impact of calorie restriction on species closest to humans.1 The researchers used rhesus monkeys which share 93% of the same genes as us and live for about 30 years. So essentially you can assume these findings from monkeys should be applicable to humans. Virtually all the earlier work on calorie restriction had been done in worms and mice which are not quite the same as humans in terms of genes or lifetime.

What was impressive about this study, was that it was a 30-year experiment to determine the long-term consequences of caloric restriction versus normal intake. When the calorie restriction was started after the monkeys had reached maturity, they didn’t live that much longer than those fed a normal diet. They did however have significantly lower levels of cancer, heart disease, and insulin resistance than controls consuming a normal laboratory diet. The authors state that there are clear parallels between humans and rhesus monkeys and that it is quite probable that the healthy effects of calorie restriction seen in monkeys will also be visible in humans.

The Advantages of a Calorie-Restricted Diet

To understand the real advantage of a calorie-restricted diet requires an understanding of the link between diet and inflammation. A calorie-restricted diet is also an anti-inflammatory diet. This means that chronic diseases with a strong inflammatory linkage such as obesity, diabetes, Alzheimer’s, heart disease, and cancer to name just a few, can either be prevented or significantly managed following such an eating plan.

One would think following an anti-inflammatory diet should be the goal of health care reform. This could be our answer to continually rising healthcare costs, especially since the majority of those costs come when we are plagued chronic disease in our last years of life? Today health care “reform” generally increases the size of your deductible before your health insurance actually kicks in. The best strategy to overcome such “reform” is simply to not to get sick in the first place. That is the promise of calorie restriction. The proof it works was demonstrated in the above mentioned 30-year rhesus monkey study.

Of course, calorie restriction in free living humans is only possible if you are never hungry or fatigued. The Zone Diet was built upon this concept. That makes the Zone Diet a lifelong dietary program to treat heart disease and diabetes by reducing inflammation. The caloric ratio of the macronutrients (carbohydrates to protein to fat) is approximately 40–30–30. This balance allows for stabilization of blood sugar to prevent hunger and fatigue.

The Zone is also nutritionally superior (if not greatly exceeding standard diet) if the carbohydrates consumed are primarily non-starchy vegetables. These will be exceptionally rich in essential nutrients including polyphenols and fermentable fiber (i.e., prebiotics) necessary for gut health.

If you take the 30% calorie restriction in the rhesus monkey study and applied it to humans, that would mean an average adult male would consume 1,500 calories per day and an average female 1,200 calories per day. It doesn’t sound like a lot a calories, but without the correct balance of macronutrients, those decreased calorie levels would likely generate constant hunger and fatigue.

Obviously, this would make it difficult to live the rest of your life regardless of the health benefits. I put forward the balance of macronutrients necessary for controlling hunger and fatigue in my first book, The Zone.2 A decade later, those same recommendations were the foundation of the new dietary guidelines of the Joslin Diabetes Center at Harvard Medical School for treating obesity and diabetes.3 This year, Joslin published their 5-year study on diabetic patients following such a dietary program.4 The results were exceptionally encouraging for all diabetics. And if they are good for diabetics, then they will be extraordinary for non-diabetics.

How to Combat Hunger on a Calorie Restricted Eating Plan

Your first thought might be: How can I comply with this monkey food business, I’ll surely die. I guarantee you that the monkeys didn’t die following a calorie-restricted diet and neither will you. How? First, the carbohydrate intake on the Zone Diet is limited to about 40% of total calories. This ensures that the brain gets its daily need for glucose, which is about 130 grams of glucose.

The Zone Diet contains 100 to 150 grams of carbohydrates (400 to 600 calories), split over three meals and one or two snacks, which easily supplies that level of glucose for optimal brain function. However, if these carbohydrates were mostly composed of non-starchy vegetables then to consume 400 to 600 calories of carbohydrates would require you to eat approximately 4 pounds per day. Although this represents only about 50 – 67% of the total amount of carbohydrates in our typical American diet, you can see it may be difficult to consume the required amounts for the Zone Diet because of the very low glycemic index of the carbohydrates.

Furthermore, you never want to consume more than 30 to 40 grams of carbohydrates at any one meal. Any greater amount is going to generate excess insulin, which makes you hungry and fatigued by driving down blood glucose levels. The result is you are constantly hungry, searching for food all the time.

The secret of the Zone Diet is that the glycemic load of a meal is balanced by adequate levels of low-fat protein (25-30 grams) at each meal to help stabilize blood sugar levels and to release satiety hormones (like PYY and GLP-1) from the gut to tell the brain to stop eating.

The Zone Paradox: Fewer Calories Doesn’t Equate to Hunger or Fatigue

Although the Zone Diet is a calorie-restricted diet, you will not be hungry or fatigued. This is the Zone Paradox. It is untrue that the Zone Diet is a high protein diet. Yet, following the Zone Diet guidelines you still get the absolute protein intake of the typical American diet because even though the percentage of protein (30% of total calories) is higher, the total number of calories being consumed daily is restricted. Because of its calorie restriction, it is also a low fat diet in absolute terms. Finally since you always consume more carbohydrates than protein, it is difficult to refer to the Zone Diet as a high-protein, low-carbohydrate diet. It’s simply not correct since you are always consuming more carbohydrates than protein at a meal. Thus, the best description of the Zone Diet it is a calorie-restricted, protein-adequate, carbohydrate-moderate, and low fat dietary plan. Who could argue with that? Obviously not the Joslin Diabetes Center at Harvard.

As Hippocrates said 2,500 years ago, “Let food be your medicine and medicine your food.” Luigi Cornaro demonstrated it works 400 years ago, and today the Zone Diet makes it possible to live better with the least amount of effort if you are willing to balance your meals to live a life without hunger or fatigue.{{cta('daffa570-1055-4766-af51-e09d66a17e47')}}References:

  1. Mattison JA et al. “Caloric restriction improves health and survival of rhesus monkeys.” Nat Comm 8:1-12 (2017).
  2. Sears B. The Zone. Regan Books. New York, NY (1995).
  3. Giusti J and Pizzotto J-A. “Interpreting the Joslin Diabetes Center and Joslin Clinic clinical and nutrition guidelines for overweight and obese adults with type 2 diabetes.” Curr Dia Rep 6:405-408 (2005).
  4. Hamdy O et al. “Long-term effect of intensive lifestyle intervention on cardiovascular risk factor in patients with diabetes in real-world practice: a 5-year longitudinal study.” BMJ Open Dia Res Care 5:e000259 (2017).

More Articles

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. 

View Article
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! 

View Article