Zone diet validation studies

Weight Loss

Any diet that restricts calories will result in equivalent weight loss. However, the same doesn’t hold true as to what the source of that weight loss is. Weight loss from either dehydration (such as ketogenic diets) or cannibalization of muscle and organ mass (such as low-protein diets) has no health benefits. Only when the weight loss source is from stored fat do you gain any health benefits. Here the Zone diet has been shown to be superior to all other diets in burning fat faster (1-4). It has been demonstrated that if a person has a high initial insulin response to a glucose challenge, then the Zone diet is also superior in weight loss (5,6). A recent study from the New England Journal of Medicine indicates that a diet composition similar to the Zone diet is superior to other compositions in preventing the regain of lost weight (7). This is probably caused by the increased satiety induced by the Zone diet compared to other diets (1,8,9).

Reduction of cellular inflammation

There is total agreement in the research literature that the Zone diet is superior in reducing cellular inflammation (10-12). Since cellular inflammation is the driving force for chronic disease, then this should be the ultimate goal of any diet. Call me crazy for thinking otherwise.

Heart disease

It is ironic that the Ornish diet is still considered one of the best diets for heart disease, since the published data indicates that twice as many people had fatal heart attacks on the Ornish diet compared to a control diet (13). This is definitely the case of don’t confuse me with the facts. On the other hand, diets with the same balance of protein, carbohydrate and fat as the Zone diet has have been shown to be superior in reducing cardiovascular risk factors, such as cholesterol and fasting insulin (14,15).


The first publication validating the benefits of the Zone diet in treating diabetes appeared in 1998 (16). Since that time there have been several other studies indicating the superiority of the Zone diet composition for reducing blood glucose levels (17-20). In 2005, the Joslin Diabetes Research Center at Harvard Medical School announced its new dietary guidelines for treating obesity and diabetes. These dietary guidelines were essentially identical to the Zone diet. Studies done at the Joslin Diabetes Research Center following those dietary guidelines confirm the efficacy of the Zone diet to reduce diabetic risk factors (21). If the Zone diet isn’t recommended for individuals with diabetes, then someone should tell Harvard.

Ease of use

The Zone diet simply requires balancing one-third of your plate with low-fat protein with the other two-thirds coming from fruits and vegetables (i.e. colorful carbohydrates). Then you add a dash (that’s a small amount) of heart-healthy monounsaturated fats. The Zone diet is based on a bell-shaped curve balancing low-fat protein and low-glycemic-index carbohydrates, not a particular magic number. If you balance the plate as described above using your hand and your eye, it will approximate 40 percent of the calories as carbohydrates, 30 percent of calories as protein, and 30 percent of the calories as fat. Furthermore, it was found in a recent Stanford University study that the Zone diet provided greater amounts of micronutrients on a calorie-restricted program than any other diet (22).

Eventually all dietary theories have to be analyzed in the crucible of experimentation to determine their validity. So far in the past 13 years since I wrote my first book, my concepts of anti-inflammatory nutrition still seem to be at the cutting edge.


  1. Skov AR, Toubro S, Ronn B, Holm L, and Astrup A. “Randomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity.” Int J Obes Relat Metab Disord 23: 528-536 (1999)
  2. Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, and Christou DD. “A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women.” J Nutr 133: 411-417 (2003)
  3. Fontani G, Corradeschi F, Felici A, Alfatti F, Bugarini R, Fiaschi AI, Cerretani D, Montorfano G, Rizzo AM, and Berra B. “Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with omega-3 polyunsaturated fatty acids.” Eur J Clin Invest 35: 499-507 (2005)
  4. Layman DK, Evans EM, Erickson D, Seyler J, Weber J, Bagshaw D, Griel A, Psota T, and Kris-Etherton P. “A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults.” J Nutr 139: 514-521 (2009)
  5. Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, and Ludwig DS. “Effects of a low-glycemic-load vs low-fat diet in obese young adults: a randomized trial.” JAMA 297: 2092-2102 (2007)
  6. Pittas AG, Das SK, Hajduk CL, Golden J, Saltzman E, Stark PC, Greenberg AS, and Roberts SB. “A low-glycemic-load diet facilitates greater weight loss in overweight adults with high insulin secretion but not in overweight adults with low insulin secretion in the CALERIE Trial.” Diabetes Care 28: 2939-2941 (2005)
  7. Larsen TM, Dalskov SM, van Baak M, Jebb SA, Papadaki A, Pfeiffer AF, Martinez JA, Handjieva-Darlenska T, Kunesova M, Pihlsgard M, Stender S, Holst C, Saris WH, and Astrup A. “Diets with high or low protein content and glycemic index for weight-loss maintenance.” N Engl J Med 363: 2102-2113 (2010)
  8. Ludwig DS, Majzoub JA, Al-Zahrani A, Dallal GE, Blanco I, Roberts SB, Agus MS, Swain JF, Larson CL, and Eckert EA. “Dietary high-glycemic-index foods, overeating, and obesity.” Pediatrics 103: E26 (1999)
  9. Agus MS, Swain JF, Larson CL, Eckert EA, and Ludwig DS. “Dietary composition and physiologic adaptations to energy restriction.” Am J Clin Nutr 71: 901-907 (2000)
  10. Pereira MA, Swain J, Goldfine AB, Rifai N, and Ludwig DS. “Effects of a low-glycemic-load diet on resting energy expenditure and heart disease risk factors during weight loss.” JAMA 292: 2482-2490 (2004)
  11. Pittas AG, Roberts SB, Das SK, Gilhooly CH, Saltzman E, Golden J, Stark PC, and Greenberg AS. “The effects of the dietary glycemic load on type 2 diabetes risk factors during weight loss.” Obesity 14: 2200-2209 (2006)
  12. 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 83: 1055-1061 (2006)
  13. Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, and Brand RJ, “Intensive lifestyle changes for reversal of coronary heart disease.” JAMA 280: 2001-2007 (1998)
  14. Wolfe BM and Piche LA. “Replacement of carbohydrate by protein in a conventional-fat diet reduces cholesterol and triglyceride concentrations in healthy normolipidemic subjects.” Clin Invest Med 22: 140-1488 (1999)
  15. Dumesnil JG, Turgeon J, Tremblay A, Poirier P, Gilbert M, Gagnon L, St-Pierre S, Garneau C, Lemieux I, Pascot A, Bergeron J, and Despres JP. “Effect of a low-glycaemic index, low-fat, high-protein diet on the atherogenic metabolic risk profile of abdominally obese men.” Br J Nutr 86:557-568 (2001)
  16. Markovic TP, Campbell LV, Balasubramanian S, Jenkins AB, Fleury AC, Simons LA, and Chisholm DJ. “Beneficial effect on average lipid levels from energy restriction and fat loss in obese individuals with or without type 2 diabetes.” Diabetes Care 21: 695-700 (1998)
  17. Layman DK, Shiue H, Sather C, Erickson DJ, and Baum J. “Increased dietary protein modifies glucose and insulin homeostasis in adult women during weight loss.” J Nutr 133: 405-410 (2003)
  18. Gannon MC, Nuttall FQ, Saeed A, Jordan K, and Hoover H. “An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes.” Am J Clin Nutr 78: 734-741 (2003)
  19. Nuttall FQ, Gannon MC, Saeed A, Jordan K, and Hoover H. “The metabolic response of subjects with type 2 diabetes to a high-protein, weight-maintenance diet.” J Clin Endocrinol Metab 2003 88: 3577-3583 (2003)
  20. Gannon MC and Nuttall FQ. “Control of blood glucose in type 2 diabetes without weight loss by modification of diet composition.” Nutr Metab (Lond) 3: 16 (2006)
  21. Hamdy O and Carver C. “The Why WAIT program: improving clinical outcomes through weight management in type 2 diabetes.” Curr Diab Rep 8: 413-420 (2008)
  22. Gardner CD, Kim S, Bersamin A, Dopler-Nelson M, Otten J, Oelrich B, and Cherin R. “Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study.” Am J Clin Nutr 92: 304-312 (2010)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

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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 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

28 thoughts on “Zone diet validation studies

  1. Dear Dr. Sears,

    My wife and myself embarked on the Zone Diet journey a few years ago and have been very happy ever since, with a small peccadillo every now and then, we are very human as you know.
    But now we undertook a new facet on our lives and I was wondering about the soundness of the Zone Diet in the light of pregnancy, which was lightning fast, surprising if you take into account that some couples plan and try for years and all we did was a trial. And if you also add to the mixture our ages… well you get the picture, not fertility treatments and suddenly surprise, so as my wife requires a bit more attention we intentionally increased by three blocks my wife´s intake to such an extent that some times she passes on a snack.

    What do you advice on this case, is the Zone Diet advised for pregnant women? We consulted with the gynaecologist and did not see any downside on the omega 3, vitamin C and polyphenol supplements. But as a new life is being developed do you have any extra advice on food and its effects on the unborn.

    Thank you.


    • The Zone diet is not a weight loss program, but a program to reduce cellular inflammation. The developing fetus needs the same anti-inflammatory nutrition as the mother. However the mother has to consume adequate protein for both her and child while keeping insulin levels from raising to unacceptable levels that would cause epigenetic changes in the fetus leading to metabolic disturbances in latter life.

      • Thank you Dr. Sears,

        We will take your advice into account and balance my wife’s diet according to your recommendations.

  2. I am a caterer also a private chef. Creating great cuisine using the zone method has kept a pounds of my body. I always recomend the zone diet to alot of my clients and have been hired to create cuisine using this method for about 11 years. Love it:)

  3. Dr Sears,

    If I have been following the zone for 7 weeks and have not seen a drop in weight but have seen a drop in inches am I doing it wrong ?

    I have noticed the following :-
    More healthier
    Metabolism is up
    Don’t ever feel hungry and cravings stopped

    When will I see a drop in body fat percentage and actual weight on the scales ?

    In addition to the zone I am also working out 6 days a week. I am just wondering if I am doing something wrong ?

    Many thanks

    • Chiggly,

      Since you work out 6 days a week, your protein/carb blocks may be too low for your activity level. That means if your working out that much, your body may be using your muscle tissue as fuel for your workout. Try increasing your blocks by one and your body will keep the muscle and burn the stored fat instead.

    • At that level of exercise, you are probably building up muscle mass. if that increase in muscle mass is matched by a corresponding decrease in body fat, then the weight on the scale will remain the same. This should be reflected in the better fit of your clothes. This is why I also recommend using the body fat calculator as opposed to simply the scale to measure your progress. However, the ultimate marker of success of the Zone diet is the reduction of cellular inflammation. That is the key to the longer life with less chronic disease.

  4. Thank you both for replying.

    I weigh 166 pounds and checked my body fat with an Accu-Measure Callipers and I am at 22.8%.
    I work out 6 days a week as I am doing P90x. I decided to clean up my fitness and eating simultaneously but didn’t want to follow the P90x nutrition guide as it suggests I eat at 2,400 cals a day which made me feel ill and bloated.

    I suffer from fibroids and find the zone easy to fit in with life in general.

    I understand about the muscle and fat but whenever I have introduced family members to the zone and so far it has sorted out my mum, brother and sister they lost loads week by week. I know its not all about weight loss but I really want to get rid of my belly fat.

    My clothes are looser I have lost inches from 37 – 33 inches in 8 weeks and gone down a size in tops but expected to see more drastic changes whilst also eating within the zone. At my weight and body fat mentioned should I be eating at 4 blocks and not 3 ? So how do I get my muscle to burn fat at a quicker rate and achieve the permanent results I am seeking ?

    Many thanks


    • At 23% body fat, you are doing an excellent job. I would confirm your body fat percentage using the Body Fat Calculator on the website. The same calculator with input from your exercise intensity will give you guidelines in the number of blocks that need to maintain your lean body mass.

  5. Dr. Sears,

    Your last sentence is continually confirmed by news reports. Yet it’s like the proverbial description of an elephant by blind men, bits and pieces are reported yet know one gets the whole picture as you have so elegantly painted it. The last time I heard you was several years ago on Dennis Prager. I wonder if your approach is to “bland” for the media’s desire to “shock and awe” it’s audience. How boring, eat your vegetables, take “cod liver oil” like grandma said, eat your protien, eat balanced, etc.. You sir are a national treasure as yet to be “discovered”. One wonders why? Your case is so obvious, so well researched and independently confirmed. What is it-Nutri Sytems I think, that has ingeniously discovered the glycemic index, again a piece of the puzzle without the overview. In a way you are like Apple vs. Microsoft, a better system, years ahead of it’s time, yet off the main stream. I am sure more will be revealed in terms of peak nutrition, e.g. the benefits of fish oil, but for now you the man. Well, I think I’ll go carbo load on some pasta then crash and burn on the first mile. All the best, I hope you find a way into more common acceptance, you may end up famous posthumously.


  6. I can’t help roaring with laughter every time I think that you can’t cure your own wife’s inflammatory intolerance to gluten.

    • The cure is very simple; never consume any grains. It’s the execution that is sometimes difficult.

      I am continually amazed that I even take the time to answer your childish comments.

  7. Dr. Sears,

    1. Extra Virgin coconut oil is being recommended by my alternative health care provider. What do you think? I already take 2 spoons of your omegarx in the morning.

    2. Also what would good AA/EPA number range be? I know that low is good, but what are those numbers? Where could I get tested, any doctor?

    3. I just received a letter from a zone counselor and think I will try that service again.

    Thank you, Margaret

    • The coconut oil is rich in tocotrienols that are good anti-oxidants, but the fatty acids are virtually all short-chain saturated fats that go directly the liver to reduce glycogen stores. It is those glycogen stores that supply glucose through the night to keep the brain nourished.

      A good AA/EPA ratio should be between 1.5 and 3 as it is in the Japanese population. The AA/EPA ratio is primarily used as a research tool, but we should be offering in September.

      I believe having your own person Zone Coach is great way to develop a lifelong dietary strategy to control cellular inflammation.

  8. In our country Indonesia, very popular Tempeh, food from fermented soybean, whould you like explain, its on good in Zona diet

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