Overweight but Healthy – It’s Quite Possible

A few medical publications have made the point that one can be overweight but fit, and have even shown that mortality is more dependent on poor physical fitness than on overweight. Now two well-controlled studies have explored this further, finding that as many as 1 in 2 overweight adults can be quite heart-healthy.

In the first study, published in the Archives of Internal Medicine, 5440 participants in the National Health and Nutrition Examination Surveys (NHANES) provided data on their body mass index (BMI) and their cardiac health. The BMI was used to classify the participants into 3 groups: normal weight, below 25.0; overweight, 25.0-29.9; and obese, 30 or above. The cardiac risk factors included raised blood pressure, triglycerides, fasting blood glucose, and C-reactive protein (CRP); and a low high-density lipoprotein cholesterol level. The results showed that 23.5% of the normal-weight participants had two or more cardiac risk factors, while 51.3% of the overweight and 31.7% of the obese adults were heart-healthy i.e. they had none or only one cardiac risk factor. The presence (or absence) of cardiac risk factors in all 3 BMI groups was correlated with their physical activity level and waist size compare with others in their BMI group.

In a second study, done in Germany and published in the same journal, 300-odd subjects in different BMI groups underwent a battery of metabolic tests as well as a test of arterial elasticity. The scientists measured total body, abdominal, and subcutaneous fat, and fat in the liver and skeletal muscle. Insulin sensitivity was also estimated. The subjects were classified into 4 groups: normal (below 25.0), overweight (25.0-29.9), obese-and-insulin sensitive (over 30.0 and high insulin sensitivity), and obese-and-insulin resistant (over 30.0 and low insulin sensitivity).

There were significant differences between the obese-and-insulin sensitive and the obese-and-insulin resistant subjects. Fat in skeletal muscle and the liver, and poor elasticity of the arteries, was lower in the obese-and-insulin-sensitive people; in particular, the level of insulin sensitivity and the degree of arterial elasticity was about the same in the obese-and-insulin sensitive and the normal BMI subjects.

The findings in this second study suggest that a relatively ‘benign’ obesity can exist that isn’t accompanied by insulin resistance or early atherosclerosis. They lend support to the results of the first study, which suggest that as many as half the overweight and a third of the obese people examined fall within this ‘benign’ class. Maybe we don’t have to shed all those pounds, after all . . .