Healthy, obese middle-aged and older men can benefit dramatically by losing weight, even when they don't exercise. But don't write off exercise in the overall health equation.
Research conducted in Baltimore and published last week in the Journal of the American Medical Association showed significant improvements in risk factors for heart disease when obese men lost 10 percent of their body weight. The nonsmoking, sedentary men involved in the study were 20 percent to 60 percent over ideal weight, but otherwise healthy. They had no history of diabetes, high blood pressure, high cholesterol or high triglycerides. Yet when they lost weight, all those measures improved.
This was not a big surprise, since numerous studies have connected increased belly fat ("apple shape") with increased heart disease risks, while connecting weight loss to improved health. What was new was the answer to the question, "Which works better alone to reduce specific heart disease risks, weight loss or exercise?" The benefits of combining the two were not tested.
All the men in the study spent three months learning to eat a heart-healthy diet that included enough calories to maintain their weight. Then they were assigned to one of three groups for the next nine months.
The "exercise" group worked out for 45 minutes three times a week on a treadmill or exercise bike and continued to eat their heart-healthy diet, including enough calories to maintain their weight.
The "diet" group met weekly. They continued their heart-healthy diet, but reduced their calories by 300 to 500 per day, just enough to lose one-half to one pound each week. They did not change their exercise habits.
The "control group" met weekly, and continued their heart healthy diet, including enough calories to maintain their weight. They did not change their exercise habits.
By the end of the study, men in the exercise group had made some significant changes. They were more physically fit, had lost a little body fat and lowered their triglycerides compared to the control group.
But the diet-only group had made even greater progress. Although they showed no improvement in fitness, they decreased their percent of body fat and total fat mass, had smaller waists, lowered both systolic and diastolic blood pressure, increased HDL (good) cholesterol and improved on several measures for diabetes risks compared to the control group.
This study was very focused, and clearly established the bottom line for obese men. Excess body fat increases your health risks. Eating a heart-healthy diet low enough in calories to lose 10 percent of your body fat improves your health and reduces your risks for diabetes, high blood pressure and coronary artery disease. All of that adds up to reduced risks for heart disease.
The study did not address obese men who already have disease symptoms, overweight but nonobese men or young obese men. Women were assigned to a different study.
Neither prevention of weight gain nor maintenance of weight loss was included in this research project. And there's the rub. Excess body fat is a health hazard. Getting it off is hard. Keeping it off is harder still. But, clearly, it's worth the effort.
And other studies show exercise plays a major role in both prevention of weight gain and maintenance of weight loss.
The Baltimore study did find that older men responded less intensely to the weight-loss program. Although they followed the diet as well as younger men, they lost only two-thirds as much weight. Consequently, their improvements in most risk areas were less dramatic.
The researchers suggest more body fat/less muscle mass, lower metabolism, less activity and lower calorie needs of older men may be the cause. That sounds suspiciously like a case for more and better exercise, especially weight training to increase muscle mass.
Colleen Pierre, a registered dietitian, is the nutrition consultant at the Union Memorial Sports Medicine Center and Vanderhorst & Associates in Baltimore.