Washington: A combo of exercise and healthy eating reduces body fat and preserves muscle in adults better than diet alone, says a study conducted by the US-based National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
NIDDK senior investigator Kevin Hall analysed the individual effects of daily strenuous exercise and a restricted diet by examining data from participants from the reality television programme "The Biggest Loser."
The programme shows obese adults losing large amounts of weight over several months. Participants were initially isolated on a ranch followed by an extended period at home, the journal Obesity reports.
"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 Hall, who has no financial ties and no other affiliation to the show, according to a NIDDK statement.
Researchers measured body fat, total energy expenditure and resting metabolic rate - the energy burned during inactivity - three times: at the start of the programme, at week six and at week 30, which was at least 17 weeks after participants returned home.
Participation in the programme led to an average weight loss of 128 pounds, with about 82 percent of that coming from body fat, and the rest from lean tissue like muscle. Preserving lean tissue, even during rapid and substantial weight loss, helps maintain strength and mobility and reduces risk of injury, among other benefits.
Hall used a math computer model of human metabolism - currently intended for research conducted by scientists and health professionals - to calculate the diet and exercise changes underlying the observed body weight loss.
The simulations also suggest that the participants could sustain their weight loss and avoid weight regain by adopting more moderate lifestyle changes - like 20 minutes of daily vigorous exercise and a 20 percent calorie restriction - than those demonstrated on the television programme.
More than two-thirds of US adults age 20 and older are overweight or obese, and more than one-third of adults are obese. Excess weight can lead to type 2 diabetes, heart disease, high blood pressure, stroke, and certain cancers.
"This study reinforces the need for a healthy diet and exercise in our daily lives," said NIDDK director Griffin P. Rodgers.