The Biggest Loser and the truth about weight loss
Nobody knows more about losing weight than contestants on the TV weight-loss programme, The Biggest Loser. Nobody knows more about putting it back on either.
Eat less, lose weight.
It's common sense, right?
Well, nobody knows how to shift excess weight like contestants on the TV programme, The Biggest Loser. It features obese men and women who battle to win a big cash prize for losing the highest percentage of body weight. Doctors and nutritionists put the contestants through dietary hell, while personal trainers beast them within an inch of their lives, episode after gruelling episode, until the winner is crowned.
Make no mistake, the results are nothing short of spectacular. Most contestants lose ten pounds (4.5kg) or more per week, with some losing as much as 30 pounds in the first week alone. Ryan Benson, who won the first series in 2004, lost 122 pounds, equivalent to 37% of his body weight, and winners since have lost even more. And because of the high levels of obesity and the intense physical training contestants undergo, most of that weight loss is fat loss.
With results like that, there must be some takeaways from The Biggest Loser that we can all learn from. There certainly are, but they might not be what you are expecting. Take the 14 contestants from the class of 2009. After completing the 30 week competition, weight loss averaged a staggering 128 pounds (58.3kg). However, research by the National Institute of Diabetes and Digestive and Kidney Diseases found that six years later, only one contestant had maintained that weight loss. Most had regained a significant amount of weight, with four being heavier than they were before appearing on the show.
Some weight regain was perhaps inevitable once the cameras stopped rolling, but this was not just a case of contestants returning to their old ways. Metabolic adaption had radically altered their physiology.
At the start of the TV series, the average Resting Metabolic Rate (RMR) of the 14 contestants was 2,607 Calories per day. RMR is similar to BMR, a measurement of energy requirement while at rest. After the 30 week contest, RMR had fallen to 1,996 Calories a day, a drop to be expected given the weight loss and what we know about metabolic adaption.
What is crazy, however, is that six years later, this metabolic adaption persisted. Indeed, the average RMR had actually fallen further to 1,903 Calories a day, meaning the contestants now needed 704 fewer Calories a day to power their bodies than they did before competing in The Biggest Loser.
Those who were most successful at maintaining weight loss experienced the greatest ongoing metabolic adaption, but, astonishingly, even those who now weighed more than they did before competing needed fewer Calories to maintain their bigger bodies.
This highlights the long-term nature of metabolic adaption. When you lose weight, you too will experience a similar physiological response. Its size and duration will vary from individual to individual, but metabolic adaption will slow the rate of weight loss and encourage weight regain in everyone, not only during the period of dieting, but for years afterwards.
This means that obese people don’t necessarily eat more than their leaner counterparts, particularly if they have lost weight. They may even eat less, but thanks to metabolic adaption, they are eating more than their body requires to maintain or lose weight.
Here’s what that might mean for you. Suppose you lose weight and now weigh the same as your normal-weight friend, Bob. Bob has never dieted and needs 2,500 Calories a day to maintain weight. You might assume that you would also need 2,500 Calories a day to maintain your new weight, given that you now weigh the same as Bob, but thanks to metabolic adaption that won’t be the case. You could consume fewer Calories than Bob and gain weight. It’s not that you are any greedier or lazier than Bob, or that you lack Bob’s willpower. You just have a lower BMR than Bob thanks to metabolic adaption.
For once, the proof isn't in the pudding
No wonder there are so many disappointed dieters out there, but this isn’t breaking news either, or at least it shouldn’t be.
In 1984, Rudolph Leibel and Jules Hirsch, two scientists at Rockefeller University, New York, published a paper entitled Diminished Energy Requirements in Reduced-Obese Patients. It compared the energy needs of obese individuals who lost weight with non-obese individuals who had never been obese. The obese individuals weighed 150kg (330lb) on average and typically lost 50kg during 200 days under hospital supervision.
Despite still weighing 60% more on average than individuals in the non-obese group, the obese participants required fewer Calories to maintain their reduced weight than the non-obese group did to maintain weight. The mean average energy requirement following the huge weight loss was 2,171 Calories a day, whereas the requirement for non-obese participants was 2,280 Calories.
This means an obese participant would have to eat 100 fewer Calories a day than a non-obese participant to prevent weight gain, despite weighing an average of 37kg (81lb) more. Going back to your friend Bob, you could lose weight but still weigh considerably more than Bob, then eat fewer Calories than Bob in a bid to lose more weight, and gain weight instead.
So much for that smaller piece of cake.
Thanks to metabolic adaption, eating less does not lead to weight loss. Not permanent weigh loss anyway, not for most people.
And that's why we advocate eating better, not less, as part of the Belly program. It's why we say counting Calories is a fool's errand and why we think counting nutrients is a much healthier option.
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Article last updated: 30th January 2021
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