Moderate weight loss in obese people improves heart function

Obese patients who lost a moderate amount of weight by eating less and exercising more improved their cardiovascular health, says a study at Washington University School of Medicine in St. Louis.

The results of this two-year study, published in the Dec. 15, 2009, issue of the Journal of the American College of Cardiology, showed that weight loss led to improvement in four key measures of heart and vascular health. The improvements seen in the study participants included decreased thickness of heart muscle, improved pumping and relaxation functions of the heart and decreased thickness of the carotid artery walls. Heart muscle thickening and impaired pumping and relaxation functions are predictors of heart failure, and increased carotid wall thickness is a predictor of plaque formation.

The researchers studied 60 moderately obese individuals at regular intervals, and 46 people (78 percent) completed the entire two-year follow-up period. The participants ranged in age from 22 to 64 and had BMIs (body mass indexes) of between 30 and 44. During the study, the subjects were instructed to eat low-calorie diets (1,200 to 1,500 calories for women and 1,500 to 1,800 calories for men) and to exercise for about three and a half hours per week, principally walking.

On average, they lost weight for about six months, reaching a maximum loss of nine percent body weight or 22 pounds. Maximum cardiovascular benefit lagged behind weight loss, with the greatest improvement coming six to 12 months after the study began.

Starting at about six months, most participants slowly regained some of their lost weight. At the end of two years, the participants averaged about nine pounds below their initial weight. Even though they regained some weight, after two years they still retained some of the heart and blood vessel benefit they had received.

"Losing 20 or so pounds might seem daunting to some people, but we showed that even a more modest weight loss can yield heart and vascular benefits," says first author Lisa de las Fuentes, M.D., a Washington University heart specialist at Barnes-Jewish Hospital and assistant professor of medicine in the Cardiovascular Division at the School of Medicine. "It's important to realize that you can choose goals that are attainable and work progressively toward them. You don't necessarily need to lose 50 pounds to improve your heart function."

The study participants were randomly assigned to either low-carbohydrate or low-fat diets. Both diet groups experienced similar improvements in heart and vascular measurements. That's reassuring for people who prefer one type of diet over the other, says de las Fuentes.

None of the patients enrolled in the study had clinically evident signs of heart failure, such as shortness of breath, coughing or fluid buildup, and none were taking cholesterol-lowering medications. About a third of them were being treated for high blood pressure.