Low-fat diet not enough to reduce cholesterol level

Jet, Sept 28, 1998

A low-fat diet is good for your health. But a low-fat diet alone is not enough to improve unhealthy cholesterol levels. You also need exercise.

"Diet alone doesn't do what people think it will," says Marcia Stefanick, associate professor of medicine at Stanford University School of Medicine in California. In fact, in some overweight people, she notes, "a low-fat diet alone may actually adversely affect levels of HDL (good) cholesterol."

But a combined low-fat diet with regular physical activity significantly improved cholesterol levels in people at increased risk of heart disease. "When you adopt healthy diet and exercise programs together, you get this tremendous benefit."

The study followed 197 men, aged 30 to 64, and 180 postmenopausal women, aged 45 to 64, who had unhealthy cholesterol levels--moderately elevated LDL (bad) cholesterol and low HDL cholesterol. Participants were randomly assigned to one of four groups: an aerobic exercise group who walked or jogged the equivalent of about 10 miles a week, a diet group who was placed on the National Cholesterol Education Program's Step 2 diet, a diet-plus-exercise group and a control group.

After a year, the diet group reduced their intake of dietary fat and cholesterol, yet showed no reduction in LDL levels. But the diet-plus-exercise group experienced a 15-point reduction in LDL levels among the women and a 20-point reduction among the men.

Numerous studies indicate that regular exercise helps improve cholesterol status.

"Even a single episode of physical activity can result in an improved blood lipid profile that persists for several days," notes the U.S. Surgeon General's 1996 Report on Physical Activity and Health.

Experts think some of this effect comes from the exercise itself and some from the weight loss that typically occurs as a result of regular physical activity.

When people exercise regularly for at least three months, "many beneficial physiological changes kick in," Stefanick notes, including an improved ability to burn fat. Yet exercise alone isn't the answer. Stefanick asserts that both eating right and exercise are essential.

And she offers some simple guidelines to eating healthy which include eating five servings of fruits and vegetables and six servings of grains each day and doing some form of moderate-intensity aerobic activity for 30 minutes at a time, at least five days a week.

Exercise benefits not only adults but children as well. Children can also improve their cholesterol levels through exercise, according to a study published in a recent issue of the journal of Pediatrics.