Many people have been inspired by the amount of weight lost by competitors on “The Biggest Loser,” a 30-week reality TV show and weight loss competition. But after the competition is over, many contestants gain most or all of the weight back. Why the backtrack? A new study may have an answer, finding that, after the dramatic weight loss, the contestants’ metabolisms slowed over time, making it harder for them to keep off the lost weight. The study was published in the journal Obesity and included 14 “Biggest Loser” contestants, ages 25 to 45. Throughout their participation in the show and during a follow-up six years later, researchers measured the participants’ body weight, among other things, and checked their resting metabolic rate (RMR)—the rate of calorie burning while at rest. They used this data to calculate how much the participants’ RMR had slowed in relation to the amount of weight they lost (also known as their metabolic adaptation). Here is what they found:
At the end of the show, the participants had lost an average of 128 pounds and RMR measurements showed that the number of calories burned per day dropped by an average of 610 since the start of the competition.
Six years later, the participants had regained an average of 90 pounds and were burning approximately the same number of calories per day as at the end of the show—an average of 704 fewer calories per day than before the competition.
There was no significant connection between the amount of weight lost and degree of metabolic adaptation at the end of the show; however, over time, participants who kept more of their weight off experienced increasing metabolic adaptation.
These findings suggest that, as the participants fought to keep the weight off, their bodies fought back by slowing their metabolism. This could explain why many (not just “Biggest Loser” contestants) struggle with weight management after weight loss. Hopefully, future research will uncover treatments for this weight loss dilemma by keeping metabolism normal and supporting healthy weight maintenance. Until then, if your weight is yo-yoing, talk with your healthcare practitioner to develop a weight loss plan that’s right for you.