Gaining it Back: The Science behind The Biggest Loser’s Failure

Dr. Sears on Biggest Loser Weight Gain

An article recently appeared in Obesity Journal that suggest that the future of America’s health is in danger. The article, which followed former contestants of The Biggest Loser, gives a graphic description of the difficulty of maintaining weight loss for any considerable length of time.

Scientists and media have been talking about the problem for years

The basic problem is that it is much easier to lose weight than keep it off. The second problem is that once someone is obese, long-term weight control becomes even more difficult. The study suggests to me that the real problem is hormone resistance, specifically, insulin resistance.

According to a Washington Post article from earlier this year on childhood obesity, it is estimated that 1/3rd of Americans born after 2000 will become diabetic. The top risk factor for diabetes is obesity from insulin resistance. An earlier article on life span projection, says that the country’s increase in obesity will lead to the first reduction in lifespan predictions in American history.

It’s not just that obesity is growing, but morbidly obese people (BMI greater than 40) are the fastest growing segment of the U.S. population. With morbid obesity comes the increased risk of diabetes and a significant increase in risk for its fellow travelers: heart disease and Alzheimer’s. This trio of chronic diseases will eventually break the back of the American health care system.

Is there a solution to America’s obesity epidemic?

How do you fix the obesity problem? The widely accepted answer is to simply “eat less and exercise more.” It’s so widely accepted that it has made the popular TV series The Biggest Loser one of the longest running reality shows in modern history. Each year, morbidly obese but relatively healthy contestants get to eat less and exercise more on national TV.

They do lose weight, but what happens after the stage lights go out? Sadly, most of them regain the weight they lost, and sometimes more. The implication is they don’t have the willpower or intelligence to keep the weight off, but the article in Obesity Journal suggests otherwise. Maybe the issue is that the show’s contestants are simply unable to fight powerful biological defenses that cause people to re-gain weight.

Why Doesn’t The Biggest Loser Work?

So why doesn’t eating less and exercising more work? First, eating less can cause stress to the system causing more hunger. The second is that the more people exercise, the hungrier they become. But don’t people lose weight on the Biggest Loser TV program? The answer is yes, because the diet they use on the TV series is essentially a version of the Zone Diet.

My book The Zone that described the Zone Diet was published in 1995. It sold more than 2 million copies and was a New York Times #1 bestseller. My follow–up books were all New York Times bestsellers as well, because the science in them was solid. It is not too surprising that when The Biggest Loser was published in 2005, the diet they used was remarkably similar to my earlier Zone books. After all, there were already 10 years of proof that The Zone works.

Comparing the Biggest Loser diet to The Zone

The Zone Pyramid that I published in my book is remarkably similar to the food pyramid published in The Biggest Loser.

Let’s compare the calories recommended by each program. For the Zone Diet, I recommend people eat between 1,200 to 1,500 calories per day. The Biggest Loser Diet, requires between 1,200 and 1,800 calories per day. The higher upper limit on the Biggest Loser Diet is a catch-all number for people who are morbidly obese because they require more calories.

The calculations used to personalize the Zone Diet cover that requirement more specifically. A person with morbid obesity has more muscle mass than the normal individual and therefore needs more protein. By calculating their protein requirements based on lean body mass using The Zone guidelines, their carbohydrate and fat requirements are more personalized, which balances their hormonal responses to the foods they eat. This will result in eating more calories, but will also result in maximal fat loss. As they lose fat, they can readjust their requirements.

The Biggest Loser Diet also recommends drinking a lot of water, eating three meals and two snacks per day and recommends that a protein serving size should be the size of the palm of the hand. Those were the exact dietary recommendations I made a decade earlier in my books. A big difference, and perhaps one of the reasons contestants’ long-term efforts failed, is that they are taken to camp (i.e. a metabolic ward) where all their meals are prepared for them. So even if they wanted to eat more calories, they couldn’t. Once they go home, they are on their own.

Wouldn’t all the exercise on The Biggest Loser help? Only a little, but it makes great TV

Remember that morbidly obese individuals already have a large amount of muscle mass since they are essentially weight training 24 hours a day because of the extra fat tissue they carry on their bodies.

Even with the most intense training  people are unlikely to add more than five pounds of muscle in 12 weeks of weight training. The reason viewers see their muscles emerging as the show goes on is because as the layer of fat surrounding the muscles is lost, muscles become more visible. Those muscles were always there but covered by a mass of fat tissue.

When I talked to the chief nutritionist of the show at conference several years ago she said, “Of course, the weight changes are all due to the diet. But who wants to see obese people eating meals? There’s no drama in eating grilled chicken and vegetables. People want to see pain, tears, and hugs in the gym. That’s great TV.”

What really happens to the contestants’ bodies after the show?

Let’s look at the data from the Obesity Journal article. The average weight of the subjects was 327 pounds. Of that starting total weight, 161 pounds was fat and the other 166 pounds of their weight was fat-free mass, which is usually described as muscle mass. At the end of 30 weeks of dieting and exercise, the contestants had lost an average of 104 pounds of fat as well as 24 pounds of muscle. As they exercised more, they required more calories. Since they didn’t take in their minimum requirement, they lost muscle mass as well as fat.

Since the maintenance of muscle mass requires calorie burn, and losing muscle mass slows the metabolism, contestants may have been better off simply eating three Zone meals and two Zone snacks per day and skipping the heavy exercise. They would have retained more of their initial muscle mass.

So why did they gain all the weight back? The answer is hormone resistance. Ultimately, weight gain, weight loss, and weight maintenance is governed by hormone communication in the gut, blood and the brain. If the hormones are not getting their signals through to the target cells, then this is called hormone resistance. The best-known example of hormone resistance is called insulin resistance.

If you have insulin resistance, then the levels of insulin increase in the blood as the pancreas secretes more insulin into the blood to accomplish its primary task, which is to reduce elevated toxic blood glucose levels as high levels of glucose are toxic.  This excess insulin in the blood also increases the deposition of fat into the fat cells and prevents its release for energy production. In essence, excess insulin in the blood makes people fat and keeps them fat. However, the same insulin resistance also prevents insulin from interacting with its receptors in the brain to tell people to stop eating.

At the molecular level, the underlying cause of insulin resistance is increased inflammation. Keeping inflammation under control is key to preventing weight from returning. Following The Zone and taking high doses of fish oil are essential to this process.

Long-term weight loss can only be attained when inflammation is resolved

Long-term weight control will only come from calorie-restriction without hunger or fatigue. This means you have to decrease insulin resistance in the gut, blood, and the brain. Following an anti-inflammatory diet like the Zone Diet and highly restricting intake of omega-6 and saturated fats in the diet for a lifetime is the only way to keep weight off.

In addition, the diet must have a low glycemic load. This is achieved by eating primarily non-starchy vegetables balanced with adequate levels of low-fat protein to keep your blood hormones in balance. This requires following a protein-adequate, carbohydrate-moderate, low-fat diet. That is the definition of the Zone Diet, and it is clinically proven.

Gastric bypass surgery is not the solution, but it does leads to a dietary discovery

Rather than recommending gastric bypass surgery, which reduces insulin resistance, I developed Zone PastaRx to reproduce many of the same hormonal changes in the gut that are generated by surgery. Our clinical trials have demonstrated that Zone PastaRx is very effective in reducing insulin resistance. In essence, it becomes a potential dietary alternative to gastric bypass. However, unlike gastric surgery, it is a desirable, convenient and sustainable source of protein which makes it easier to follow the Zone Diet for a lifetime.

The best part is that the same clinical trials that indicated Zone PastaRx builds lean body mass and reduces fat is just like being on The Biggest Loser but without the screaming trainers.

The Zone Insulin Resistance Calculator helps determine your extent of insulin resistance, and also provides clinically-based dietary recommendations that may help reduce your levels of insulin resistance. See your Insulin Resistance Score, and Zone recommendations tailored to you, and what you can do to reduce it.


  1. Fothergill E et al. “Persistent metabolic adaption 6 years after ‘The Biggest Loser’ competition.” Obesity 24: doi: 10.1002/oby.21538 (2016).
  2. Skinner AC et al. “Prevalence of obesity and severe obesity in US children, 1999-2015.” Obesity 24:1116-1123 (2016).
  3. Ferdman RA. “A widely held belief about childhood obesity that simply isn’t true.” Washington Post. May 2, 2016.
  4. Narayan KM et al. “Lifetime risk for diabetes mellitus in the United States.” JAMA 2003 290:884-1890 (2003).
  5. Olshansky SJ et al. “A potential decline in life expectancy in the United States in the 21st century.” N Eng J Med 352: 1138-1145 (2005).
  6. Sears B. The Zone. Regan Books. New York, NY (1995).
  7. Sears B. Mastering the Zone. Regan Books. New York, NY (1997).
  8. Sears B. Zone Meals in Minutes. Regan Books. New York, NY (1997).
  9. Greenwood-Robinson M. The Biggest Loser. Rodale. Eramus, PA (2005).
  10. Sears B. Toxic Fat. Thomas Nelson. Nashville, TN (2005).
  11. Sears, B. The Mediterranean Zone. Ballantine Books. New York, NY (2014).
  12. Sears B and Perry M. “The role of fatty acids in insulin resistance.” Lipids Health Dis 14:121 (2015).
  13. Edholm D et al. “Long-term results 11 years after primary gastric bypass in 384 patients.” Sur Obesity and Related Dis 9:708-713 (2013).
  14. Kolata G. “After ‘The Biggest Loser’, their bodies fought to regain weight.” New York Times. May 2, 2016.
  15. Chan JL et al. “Peptide YY levels are elevated after gastric bypass surgery.” Obesity 14:194-198 (2006).
  16. Ludwig DS et al. “High glycemic index foods, overeating, and obesity.” Pediatrics 103:E26 (1999).
  17. Agus MS et al. “Dietary composition and physiologic adaptations to energy restriction.” Am J Clin Nutr 71:901-907 (2000).

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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 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. Phil White

    For past six years have been on an all organic, gluten free (GF) eating regimen which seems to have worked quite well for me… but, just recently discovered and read the Mediterranean Zone (MZ)… very much like what I read and am trying to transition over to it as best I’m able… the MZ calls for no white bread, white rice, white potatoes or pasta… does that also exclude GF white bread and GF pasta?… does it exclude sweet potatoes (yams)?… without those, I’m having trouble satisfying my need for variety.

    Also, I have never enjoyed vegetables but, am using a Nutri-Bullet to make vegetable and fruit shakes which I mix to try to make them palatable enough to enjoy… will that take me out of the zone?

    • Dr. Sears

      Gluten-free bread and pasta have a higher glycemic response than their gluten-containing cousins. In essence, they are glorified candy bars. Sweet potatoes are still high in their glycemic load. I would suggest dropping the gluten-free bread and pasta entirely and significantly cut back on the yams and replace those items with more non-starchy vegetables and limited amounts of fruits. There is plenty of variety in those two groups of carbohydrates that will generate a far better hormonal outcome.

    • Phil White

      I appreciate your prompt and candid reply… am working hard to learn to eat veggies… what about the Nutri-Bullet?… does grinding the veggies and fruit up like that cause any problems?

      • Dr. Sears

        The Nutri-Bullet is a definite alternative. The only small drawback is that lightly cooking the vegetables helps release more nutrients from the cell walls.

  2. chris stephens

    is there an easy way to get notifications when Dr Sears responds to questions/comments in the comments section of each post? i just scanned through several older posts and didn’t realize how much i missed. I can’t find an RSS feed.

    • Dr. Sears

      Chris – Thanks for the comment. This is functionality we are looking to add to the site in an upcoming release.

  3. Jo

    Great post. I know the Zone works because I have followed its principles since I first discovered it (about 10 years ago). Can’t say enough good things, I feel great and everyone thinks I am much younger. I am now helping my patients to be the best version they can be. Greetings from northern Mexico 🙂

  4. Shaun Healy

    But the real surprise in this study was that these contestants, basically following a Zone diet, and allowed slightly more calories than the Zone diet calls for, saw their basic metabolic rate drop dramatically. And the real shocker was that this drop stayed in place even a year after the show ended. That’s WHY they all gained the weight back. That was the primary and most important conclusion of the entire study. Dr Sears, with all due respect,ignores this. If these contestants followed a Zone diet, and their calorie restriction resulted in a huge drop in their metabaloic rate, how would anyone following Zone diet escape this same result. And simply asserting that human beings can follow a restricted 1200-1600 calories diet, and not experience hunger, is supposition, not science. There are a myriad of scientific studies that completely and conclusively contradict that assertion.

    • Dr. Sears

      If you read the actual published paper, then you would see that the RMR measured six years earlier were estimated values, not clinically validated numbers. Data published by Harvard Medical School in 2000 demonstrated a significant attenuation of the reduction of the metabolic rate accompanied with weight following the Zone Diet compared to equal weight loss on a standard isocaloric diet. The Zone Diet was developed to reduce insulin resistance (HOMA-IR) and it was significantly reduced for the first 30 weeks. The weight regain can is explaining by the dramatic increase in HOMA-IR that was significantly higher six years after the completion of the competition than before the competition started six years earlier. Relative to following a 1,200 to 1,500 calorie diet for extended period of time, I would refer you to the long-term data in the National Weight Control registry of obese individuals who have successfully maintained much of their initial weight loss. Their average calorie intake is 1,450 calories per day. Of course gastric bypass surgery remains the gold standard for long-term weight maintenance, but the subjects still remain overweight on a limited calorie intake. I would be happy to study the myriad of studies that you mention. Finally please notice that one of the 14 subjects not only lost weight during the competition (87 pounds), but continued to lose another 22 pounds during the next six years.

  5. Mary Rose

    I read a lot about nutrition and agree this is one of the best articles I’ve read summing up a good diet — and especially a useful summary of the Zone.

  6. Omar

    I tried the zone diet back in 1995-96; stayed in it for over 180 days and I got unbelievables results and I passed it over to my cousins which were amaze about the results.
    Nowdays I still use it when I want to slim down and get my body back.
    One of the best proven diet.

    • Dr. Sears

      Thank you for your kind comments. However the secret to Evidence-based Wellness to continue to the follow the Zone Diet for a lifetime.

    • Dr. Sears

      The 40-30-30 balance of macronutrients is simply the center of a bell-shaped curve for optimal control of dietary response. In reality is the really the balance of protein-to-glycemic load that determines much of those hormonal responses. Your primary indicator that you have found the right balance is lack of hunger without fatigue for the next five hours after eating a meal.

  7. Ari

    I have been following zone diet for over a month now and I love it. It is works withou one starving himself or herself!
    Thank you so much!

  8. Jim Hall

    This is one of the best articles I have read on weight loss and I didn’t even have to pay for it.


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