Your diet may help you lose weight, but exercise appears to be the key to keeping it off.
A new study, published in the journal Obesity, tracked 14 former Biggest Loser contestants to determine how some of them kept weight off after the show. Physical activity, the researchers determined, was the clear answer — even though diet, not exercise, was shown to help the contestants lose weight in the first place.
Half of the study participants maintained their weight loss after the Biggest Loser ended, while the other half gained the pounds back. Over six years of follow-up, the maintainers tended to be far more active than the other group, increasing physical activity by up to 160% since they started losing weight. Those who regained weight, by contrast, only increased physical activity by 25% to 34%. Overall, maintainers completed an average of 80 minutes of moderate exercise or 35 minutes of vigorous exercise each day — well exceeding the national physical activity guidelines of 150 minutes of moderate exercise or 75 minutes of vigorous exercise per week.
The findings tie into another study published by the same researchers last year. Back then, they found that contestants' metabolisms slowed drastically after their dramatic weight losses, significantly cutting into the number of calories they were able to burn each day. As a result, many contestants saw the pounds creep back on, sometimes even exceeding their pre-show weights.
Exercise, the new study suggests, may counteract that effect, helping people burn enough calories to stay thin. But the time commitment of a robust fitness regimen can make weight maintenance an uphill battle, according to former Biggest Loser contestant and study author Dr. Jennifer Kerns, who is now an obesity specialist at Washington's Veterans Affairs Medical Center.
“The amount of time and dedication it takes to manage one’s food intake and prioritize exercise every day can be an untenable burden for many people," Kerns told the New York Times. "It's totally unfair to judge those who can't do it."