Exercise coupled with
healthy eating reduces body fat and preserves muscle better than diet alone,
according to a study that used info from Biggest Loser contestants.
The National Institute
of Diabetes and Digestive and Kidney Diseases, part of the National Institutes
of Health, analyzed the effects of daily strenuous exercise and a restricted
diet by examining data from participants of The Biggest Loser.
"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
Kevin Hall, Ph.D., senior investigator in a press release on the Biggest Loser study.
Researchers measured
the body fat, total energy expenditure, and resting metabolic rate of each
participant at the start of the program, at week 6, and at week 30.
Participants lost an average of 128 pounds, with about 82 percent of that
coming from body fat and the rest from lean tissue, like muscle.
Because the TV show
doesn’t directly address how exercise and diet separately contributed to the
participants’ weight loss, Hall used a computer model of human metabolism to
simulate the results of diet alone and exercise alone; he then estimated their
relative contributions to overall weight loss.
Hall and his team
found that diet alone led to 65 percent of the body-fat weight loss, and 35
percent of lean tissue weight loss. The model showed that exercise alone
resulted in participants losing only fat and no muscle. The simulation of
exercise alone also estimated a small increase in lean muscle mass despite
overall weight loss, according to the release.