The Biggest Loser study: Why contestants can’t keep the kilos off

(Trigger warning: Unsafe dieting practices, weight, calories)

By Georgina Lavan

Earlier this month, the Obesity Journal released astonishing results on a study conducted on contestants from the NBC series ‘The Biggest Loser’, determining whether physiological factors played a role in the obesity epidemic and the unsuccessful long term weight loss of the hit reality show contestants. Fourteen of the 16 contestants (six men, eight women) in the 2009 season participated in the study at the National Institute of Health Clinical Centre in Maryland. They were tested for body weight, fat, hormone levels and most importantly, resting metabolic rate (RMR), the number of calories we burn when resting. This was of particular interest due to the phenomenon observed by researchers known as “metabolic adaptation”, where one’s basal metabolic rate slows down during weight loss. We have written about this principle previously here.

During the shows initial weigh in, contestants weighed an average of 148.9 kilograms, dropping down to an average of 90.6 kilograms by the end of the 30 week filming program of rigorous exercising and restricted dieting. In the six years since filming the series, 13 of the contestants were found to have gained weight, averaging 131.6 kilograms, with four contestants heavier now than before the competition.

One of the main causes of weight gain, as noted by the shows in house doctor, Robert Huizenga, was the lack of resources when contestants returned to the outside world. “Unfortunately, many contestants are unable to find or afford adequate ongoing support with exercise doctors, psychologists, sleep specialists, and trainers”. He has suggested that following the show, contestants need to carry out a minimum of nine hours exercise per week as well as diet monitoring to ensure weight maintenance – a vast difference to the reported seven hours of exercise a day whilst in the house, estimated to burn between 8000 and 9000 calories.

However, the study also found that whilst the contestant’s weight yo-yoed over the years, their resting metabolic rate continued to decrease. Prior to filming, contestants were burning sufficient calories for their weight, averaging an RMR of 2607 calories. In the years following, it was found that the radical reduction in weight resulted in their metabolisms slowing down, resulting in fewer calories being burnt to maintain their newer, thinner physiques (1903 calories RMR). On average, contestants were burning 500 calories less than those who had similar body compositions and had not engaged in a weight loss program; requiring them to eat less food in order to maintain their weight. This fits in line with previous studies that have found that weight loss participants showed RMR levels that were three to five percent lower when compared to control participants with similar body compositions (Astrup, Gotzsche, van de Werken, Ranneries, Toubro, Raben, & Buemann, 1999).


Danny Cahill’s TBL before and after shots

Interestingly, contestants who managed to lose the most kilos during filming were found long term to have the greatest damage to their resting metabolic rate (Johanssen, Knuth, Huizenga, Rood, Ravussin, Hall, 2012). Danny Cahill, who was the show’s bigger loser in 2009, achieved his win by committing to a full-time job of diet and exercise during his at home training, before returning for the show’s finale. His day would consist of early morning rises accompanied with two treadmill sessions, bike riding to and from the gym, two and a half hour gym sessions, and a diet consisting of egg whites, grilled chicken and vegetables.

Whilst realistic that he would not be able to maintain his full weight loss after filming, the land surveyor and musician could not understand why getting back to normal life post production took such a toll on his body. Since losing 108.5 kilograms, he has regained 47.2 kilograms in the years since the show, weighing in at 133.8 kilograms. When comparing his calorie consumption with his friends, he struggled to understand why a social ritual such as having a beer would result in greater weight gain for him compared to his friends. He has now discovered through this study that his body is burning 800 fewer calories a day than other men of his size.

Erinn Egbert was the only contestant in the study who was found to weigh less than when she completed filming of the show. As a full-time carer of her mother, she struggles to maintain this weight; her RMR results showing that her body burns 552 calories less than what is expected for her size. She has vocalised that often she must be mindful of her “treat” periods, as they can turn into several day binges. This is not unexpected, as many contestants have noted their continuous struggles with hunger pains, food cravings and at times, binge eating. Previous studies carried out in Minnesota have found that when participants were left to consume a non-restricted diet after periods of starvation, they often consumed well above their calorie requirements, whilst their RMR rate continued to decline (Keys, 1950).


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Danny Cahill, 2016

The question is, was it all worth it for the contestants?

Whilst there are the so called perks of television exposure, sponsorship campaigns and press tours post production, they, like the weight loss, appear to be short lived. Long term, the contestants have suffered the physiological damages of the weight loss, as well as emotional changes resulting in marriage breakdowns, job losses, and mood disorders. One alumni contestant and Hurricane Katrina survivor, Lezlye Donahue, described the show as “her biggest nightmare”.

It appears that whilst the fifteen minutes of fame provides contestants with a happy ever after moment on screen, off screen, however, the full-time hours required to maintain their new physiques whilst juggling family, work and a social life is unrealistic. Further medical and emotional supports are clearly required for contestants to develop a healthy and realistic relationship with their bodies once leaving The Biggest Loser house.

In summary, reality television weight loss programs are impractical and a poor example for viewers who are attempting to diet in the real world. Furthermore, this study highlights the pervasive and long term health risks associated with dieting, exhibiting many real life examples of people dieting themselves fat. If you would like to improve your relationship with your food and/or exercise, contact BodyMatters Australiasia for further information.


Original Article:

Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., … & Hall, K. D. (2016). Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity.


Astrup, A., Gotzsche, P. C., van de Werken, K., Ranneries, C., Toubro, S., Raben, A., & Buemann, B. (1999). Meta-analysis of resting metabolic rate in formerly obese subjects. The American journal of clinical nutrition69(6), 1117-1122.

Johannsen, D. L., Knuth, N. D., Huizenga, R., Rood, J. C., Ravussin, E., & Hall, K. D. (2012). Metabolic slowing with massive weight loss despite preservation of fat-free mass. The Journal of Clinical Endocrinology & Metabolism97(7), 2489-2496.

Keys A. The Biology of Human Starvation. University of Minnesota Press: Minneapolis; 1950

Nackers, L. M., Ross, K. M., & Perri, M. G. (2010). The association between rate of initial weight loss and long-term success in obesity treatment: does slow and steady win the race?. International journal of behavioral medicine,17(3), 161-167.

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