Nutrition
The older we get, the fewer calories we need, but many do not change their eating habits
18 years, 11 months ago
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Posted on Apr 21, 2005, 6 a.m.
By Bill Freeman
As we age, our bodies need fewer calories to keep going, says Loren Lipson, MD, associate professor of medicine at the Keck School of Medicine of USC. But many Americans fail to change their eating habits to adjust for the lower requirement.
As we age, our bodies need fewer calories to keep going, says Loren Lipson, MD, associate professor of medicine at the Keck School of Medicine of USC.
But many Americans fail to change their eating habits to adjust for the lower requirement. “We should be at our peak weight in our late 20s and early 30s, but many of us continue to gain weight as we get older,” he says.
Studies show adults' caloric needs drop about 10 percent or more from about age 30 to age 65 and older. Some of that decline may reflect a relative lack of physical activity in the elderly, and some may represent the body's basal metabolism slowing during aging.
Part of the reason is that the body loses muscle - a prime consumer of energy - during the senior years.
“For example, if you take an active, 150-lb. man of 25, he may be about 45 percent muscle. But the same man with the same height and weight at 75 may be only 27 percent muscle. These changes have profound effects: The same muscles have to carry around the same weight, but with a 40 percent reduced muscle mass. This is, in part, the reason that seniors have difficulty getting around and doing things,” Lipson says.
Lipson says that people should pay attention to their diet as they grow older and opt for smaller portions.
More important, however, is keeping physically active, he says.
“These body changes are neither irreversible nor permanent. Many seniors are actually able to add muscle mass and function into their 90s,” Lipson notes. “You can defy what normal aging does to body composition by a careful balancing of food intake, exercise and vitamins.”
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But many Americans fail to change their eating habits to adjust for the lower requirement. “We should be at our peak weight in our late 20s and early 30s, but many of us continue to gain weight as we get older,” he says.
Studies show adults' caloric needs drop about 10 percent or more from about age 30 to age 65 and older. Some of that decline may reflect a relative lack of physical activity in the elderly, and some may represent the body's basal metabolism slowing during aging.
Part of the reason is that the body loses muscle - a prime consumer of energy - during the senior years.
“For example, if you take an active, 150-lb. man of 25, he may be about 45 percent muscle. But the same man with the same height and weight at 75 may be only 27 percent muscle. These changes have profound effects: The same muscles have to carry around the same weight, but with a 40 percent reduced muscle mass. This is, in part, the reason that seniors have difficulty getting around and doing things,” Lipson says.
Lipson says that people should pay attention to their diet as they grow older and opt for smaller portions.
More important, however, is keeping physically active, he says.
“These body changes are neither irreversible nor permanent. Many seniors are actually able to add muscle mass and function into their 90s,” Lipson notes. “You can defy what normal aging does to body composition by a careful balancing of food intake, exercise and vitamins.”
USC Health Sciences
Visit our experts directory at:
http://www.usc.edu//uscnews/experts
