When you're trying to lose weight there are two words that can motivate just about anyone: goal weight. But what happens next, after you reach that coveted number? For most "Biggest Loser" contestants, what happens is that they gain the weight back — but not all of them.
A new study of "Biggest Loser" contestants uncovers one reason why some contestants succeed at weight-loss maintenance, when others don’t. People who live an extremely active daily lifestyle — including at least 80 minutes of moderate activity or 35 minutes of vigorous activity — maintain their weight loss.
“The messaging is you can keep the weight off, but you have to find a way to incorporate a lot of exercise into everyday life,” said Kevin Hall, an author of the paper in the journal Obesity, and chief of the Integrative Physiology Section at the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland.
To understand why some maintained their weight loss and others re-gained, Hall and his colleagues looked at 14 former "Biggest Loser" contestants.
The researchers took measurements six weeks after the contestants were selected for the show, then 30 weeks later, and then six years later.
While many studies rely on self-reported data that can be unreliable, Hall used methods that calculated calorie intake and expenditure to more objectively provide a reliable picture.
The researchers looked at participants that fell into two groups. Seven participants who regained, on average, 5 pounds more than their starting weight and seven who maintained an average loss of 81 pounds.
Those who maintained their loss included more exercise in their daily lives, even years after the contest ended.
“The study is confirmatory that physical activity is really the key to long-term weight-loss maintenance. Even six years after, even people who have lost 25 percent of their weight, can maintain,” said Dr. Sangeeta Kashyap, an endocrinologist at Cleveland Clinic, who was not involved in the study.
While the study looks at a small, unique population, it reinforces what weight-loss experts believe works best for maintaining a healthy weight after losing.
“We really try to make this clear up front that weight loss isn’t a temporary thing. It is a lifestyle change," said Tom Hritz, clinical nutrition director at Magee-Womens Hospital of University of Pittsburgh Medical Center, who wasn't involved in the study.
“When you are looking to lose weight, you really want to focus on diet and once you have reached that goal and you want to maintain then you really need to incorporate exercise," Hritz explained.
While the study finds that people who maintained their loss were active more than what is recommended, not everyone was a “gym rat,” Hall said. The 80 minutes a day might include walking to work, for example. The study did not look at what types of exercise people did.
The Centers for Disease Prevention and Control (CDC) recommends that adults ages 18 to 64 participate each week in 150 minutes of moderate activity, something like brisk walking, slow bike riding, dancing or gardening. Or, people can weekly do 75 minutes of vigorous activity, such as running or swimming. The CDC also urges two days of strengthening activities.
One reason why people struggled to maintain weight loss is that "Biggest Loser" contestants have a slowed metabolism and burn 500 fewer calories than they should. The researchers remain unsure why, but Hall said the study provides hope.
“We are actually showing that it is possible for people to maintain weight loss but they have to do it with substantial physical activity,” he said.