What viewers of the show “The Biggest Loser" didn’t see on TV was some research going on behind the scenes. Researchers analyzed data from 11 participants from the reality show, which follows obese people isolated on a ranch where they begin losing large amounts of weight through exercise and diet.
The study, by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health and published online in the journal Obesity, concluded that exercise is a crucial component, in addition to healthy eating, to preserve muscle in adults.
“By including the show’s contestants as voluntary study participants, this research took advantage of a cost-efficient opportunity to study a small group of obese individuals already engaged in an intensive lifestyle intervention," said senior investigator Kevin Hall of the National Institutes of Health. He has no affiliation with the show.
Researchers measured body fat, total energy expenditure and resting metabolic rate (energy burned during inactivity) at the start of the program, at week six, and at week 30, which was at least 17 weeks after participants returned home from the ranch.
Participants lost an average of 128 pounds, 82 percent of which was body fat, the rest of which was muscle.
Preserving lean tissue helps maintain strength and mobility and reduces risk of injury, among other benefits.
Hall used a mathematical computer model of human metabolism to calculate how diet alone or exercise alone contributed to participants’ weight loss.
In conclusion, diet alone was calculated to be responsible for more weight loss than exercise, with 65 percent of the weight loss consisting of body fat and 35 percent consisting of lean mass like muscle.
Exercise alone resulted in participants losing only fat, and no muscle. Exercise alone also was calculated to be responsible for a small increase in lean mass despite overall weight loss.
— Anne Aurand, The Bulletin