People typically lower their risks of heart disease and premature death far more by gaining fitness than by dropping weight.
For better health and a longer life span, exercise is more important than weight loss, especially if you are overweight or obese, according to an interesting new review of the relationships between fitness, weight, heart health and longevity. The study, which analyzed the results of hundreds of previous studies of weight loss and workouts in men and women, found that obese people typically lower their risks of heart disease and premature death far more by gaining fitness than by dropping weight or dieting.
The review adds to mounting evidence that most of us can be healthy at any weight, if we are also active enough.
I have written frequently in this column about the science of exercise and weight loss, much of which is, frankly, dispiriting, if your goal is to be thinner. This past research overwhelmingly shows that people who start to exercise rarely lose much, if any, weight, unless they also cut back substantially on food intake. Exercise simply burns too few calories, in general, to aid in weight reduction. We also tend to compensate for some portion of the meager caloric outlay from exercise by eating more afterward or moving less or unconsciously dialing back on our bodies’ metabolic operations to reduce overall daily energy expenditure, as I wrote about in last week’s column.
Glenn Gaesser, a professor of exercise physiology at Arizona State University in Phoenix, is well versed in the inadequacies of workouts for fat loss. For decades, he has been studying the effects of physical activity on people’s body compositions and metabolisms, as well as their endurance, with a particular focus on people who are obese. Much of his past research has underscored the futility of workouts for weight loss. In a 2015 experiment he oversaw, for instance, 81 sedentary, overweight women began a new routine of walking three times a week for 30 minutes. After 12 weeks, a few of them had shed some body fat, but 55 of them had gained weight.
In other studies from Dr. Gaesser’s lab, though, overweight and obese people with significant health problems, including high blood pressure, poor cholesterol profiles or insulin resistance, a marker for Type 2 diabetes, showed considerable improvements in those conditions after they started exercising, whether they dropped any weight or not. Seeing these results, Dr. Gaesser began to wonder if fitness might enable overweight people to enjoy sound metabolic health, whatever their body mass numbers, and potentially live just as long as thinner people — or even longer, if the slender people happened to be out of shape.
So, for the new study, which was published this month in iScience, he and his colleague Siddhartha Angadi, a professor of education and kinesiology at the University of Virginia in Charlottesville, began scouring research databases for past studies related to dieting, exercise, fitness, metabolic health and longevity. They were especially interested in meta-analyses, which pool and analyze data from multiple past studies, allowing researchers to look at results from far more people than in most individual studies of weight loss or exercise, which tend to be small-scale.
They wound up with more than 200 relevant meta-analyses and individual studies. Then they set out to see what all of this research, involving tens of thousands of men and women, most of them obese, indicated about the relative benefits of losing weight or getting fit for improving metabolisms and longevity. In effect, they asked whether someone who is heavy gets more health bang from losing weight or getting up and moving.
