And the exercise group, along with the control group, lost no weight.
It's not surprising that those who only exercised didn't shed pounds, Villareal said. "There's a myth that exercise is effective in inducing weight loss," he said, adding that exercise must be intense to cause people to shed pounds.
Overall, the researchers reported in their study, diet or exercise alone did improve physical function, by about 12 percent and 15 percent, respectively. But a combination of diet and exercise improved overall physical performance by 21 percent.
That's important because "obesity exacerbates the age-related decline in physical function, which causes frailty, impairs quality of life, and results in increases in nursing home admissions," they noted in the study.
The findings make sense, said Alice H. Lichtenstein, director of the Cardiovascular Nutrition Laboratory at Tuft University's Jean Mayer USDA Human Nutrition Research Center on Aging. "It's impressive that they were able to get the people to adhere to a diet and to engage in physical activity," she added.
For more about obesity, try the U.S. National Library of Medicine.
SOURCES: Dennis T. Villareal, M.D., chief of geriatrics, New Mexico VA Medical Center, and professor, medicine, University of New Mexico, Albuquerque; Alice H. Lichtenstein, D.Sc., professor, nutrition science and policy, and director and senior scientist, Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston; March 31, 2011, New England Journal of Medicine
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