Dieting alone isn’t enough for most people to shed pounds and keep the weight off. That’s the latest word from health experts who say healthy dieting must be combined with a regular exercise program to reduce body fat and preserve muscle in adults.
The findings of the study — funded and conducted by National Institute of Diabetes and Digestive and Kidney Diseases, part of the National Institutes of Health — are based on an analysis of the effects of daily strenuous exercise and a restricted diet on 11 participants from the reality TV series, "The Biggest Loser." The program tracks obese adults losing large amounts of weight over several months.
SPECIAL: These 5 Things Flush 40 lbs. of Fat Out of Your Body — Read More.
"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 lead researcher Kevin Hall, who has no financial ties or affiliation to the show.
For the study, published online in the journal Obesity, researchers measured the contestants’ body fat, energy expenditure, and resting metabolic rate — the energy burned during inactivity — at the start of the program, after six weeks, and again after 30 weeks.
Participants lost an average weight of 128 pounds, with about 82 percent of that coming from body fat, and the rest from lean tissue like muscle.
Hall used a computer model to calculate how much of the weight loss was due to diet and how much to exercise. He found diet alone was responsible for more weight loss than exercise, but that participants could sustain their weight loss and avoid weight regain by combining the two strategies — engaging in 20 minutes of daily vigorous exercise and cutting 20 percent of calories from their diet.
SPECIAL: These 5 Things Flush 40 lbs. of Fat Out of Your Body — Read More.
"This study reinforces the need for a healthy diet and exercise in our daily lives," said NIDDK Director Dr. Griffin P. Rodgers. "It also illustrates how the science of metabolism and mathematical modeling can be used to develop sound recommendations for sustainable weight loss — an important tool in the treatment of obesity — based on an individual's unique circumstances."
More than two-thirds of U.S. adults are overweight or obese, which raises the risk of type 2 diabetes, heart disease, high blood pressure, stroke, and certain cancers.