A new study debunks the widely held belief that diet plus exercise is the most effective way to lose weight. Researchers report that dieting alone is just as effective as dieting plus exercise.

“For weight loss to occur, an individual needs to maintain a difference between the number of calories they consume everyday and the number of calories they burn through metabolism and physical activity,” Dr. Leanne Redman of the Pennington Biomedical Research Center in Baton Rouge, Louisiana, explains in a press release.

“What we found was that it did not matter whether a reduction in calories was achieved through diet or burned everyday through exercise.”

Thirty-five overweight but otherwise healthy adults - 16 men and 19 women - completed the 6-month study. Twelve were assigned to a diet-only group; they reduced their calorie intake by 25 percent. Twelve were assigned to diet plus exercise; they reduced their calorie intake by 12.5 percent and increased their exercise by 12.5 percent. The remaining 11 subjects made no significant diet or exercise changes.

Redman and colleagues found that the diet-only group and the diet plus exercise group lost roughly the same amount of weight, albeit by different means. They lost about 10 percent of their body weight, 24 percent of their fat mass and 27 percent of their abdominal “visceral” fat - the deep internal fat linked to heart disease risk.

Therefore, if the goal is purely shedding pounds, diet or exercise will work, according to this study. However, as the researchers point out, regular exercise can improve aerobic fitness and lower the risk of heart disease, diabetes, and certain types of cancer.

The study also found that exercise did little to tone specific areas of the body. Fat was reduced consistently across the whole body and not more in any one trouble spot.

“Our study then would indicate that weight loss cannot override the way in which any individual stores fat. Perhaps an apple will always be an apple, and a pear, a pear,” Redman concludes.

This suggests that people are “genetically programmed for fat storage in a particular pattern and that this programming cannot be easily overcome by weight loss,” the authors note in the Journal of Clinical Endocrinology and Metabolism.

SOURCE: Journal of Clinical Endocrinology and Metabolism 2007.