Gretchen Reynolds

CNA – A study of the results of hundreds of previous studies on weight loss and workouts in men and women found that obese people typically reduce their risk of heart disease and premature death much more than by losing weight or dieting.

The review adds to the growing evidence that most of us can be healthy at any weight if we are active enough.

I’ve often written in this column about the science of exercise and weight loss, and many of them are actually disappointing if your goal is to be slimmer.

This past research fully shows that people who start exercising rarely lose a lot of weight, if at all, unless they significantly reduce their food intake.

Exercising burns too few calories in general to help reduce weight.

In addition, we tend to compensate for some of the low-calorie expenditure of exercise by then eating more or moving less, or subconsciously marking our body’s metabolic operations to reduce our overall daily energy expenditure.

Glenn Gaesser, a professor of exercise physiology at Arizona State University in Phoenix, is well aware of the shortcomings of fat loss workouts.

Over the decades, he has been studying the effects of physical activity on people’s body composition and metabolism, as well as their endurance, with a particular focus on obese people.

His past research has highlighted the need for weight loss workouts.

In a 2015 experiment she oversaw, for example, 81 sedentary and overweight women began a new routine of walking three times a week for 30 minutes.

After 12 weeks, some of them removed some body fat, but 55 of them gained weight.

In other studies by Dr. Gaesser’s lab, however, people who were overweight and obese had serious health problems, including hypertension, a low cholesterol profile, or insulin resistance, a marker of type 2 diabetes, which showed significant improvements in these conditions after exercise. whether they dropped any weight or not.

Seeing these results, Dr. Gaesser began to wonder whether overweight people would be able to enjoy good metabolic health, regardless of their body mass, and potentially live as long as thinner people, or even if slender people were away. . form.

So for the new research published this month Science, A professor of education and kinesiology at the University of Virginia in Charlottesville, and Siddhartha Angadi began researching databases for past research related to diet, exercise, metabolic health, and endurance.

They were particularly interested in meta-analyzes, which collected and analyzed data from several past studies, allowing researchers to analyze the results of many more people than in most individual weight loss or exercise, which are usually small-scale.

They ended with 200 important meta-analyzes and individual analyzes. Then, all of this research, tens of thousands of men and women, most of them obese, set out to see what they represent about the relative benefits of improving metabolism and endurance.

In fact, someone who was overweight was asked if losing weight or lifting and moving takes on more health.

The competition, they saw, was not closed. “Compared to head-to-head, the benefit was greater as a result of improved fitness than as a result of weight loss,” Dr. Gaesser said.

Overall, the research they cite shows that sedentary and obese men and women who start exercising and improve their condition can reduce their risk of premature death by 30 percent or more, even if their weight does not change.

This improvement generally puts them at a lower risk of premature death than normal weight but out of shape people, Dr. Gaesser said.

On the other hand, if heavy people lose weight on diets (not diseases), the statistical risk of dying young usually drops by about 16 percent, but not in all studies.

Studies cited in the new review show that weight loss among obese people does not reduce the risk of death at all.

The new review was not designed to determine how exercise or weight loss affects the lifespan of obese people.

But in many of the studies they studied, Dr. Gaesser said, people who lost pounds on a diet regained it and then tried it again, a yo-yo approach to weight loss that often helps with metabolic problems like diabetes and high cholesterol and reduced life expectancy. .

On the other hand, the exercise addresses these conditions, he said. It may also accidentally regenerate people’s fat stores.

“People with obesity usually lose belly fat when they exercise,” he said, although overall weight loss is negligible.

Intestinal fat, which is stored inside our body, increases the risk of developing type 2 diabetes, heart disease and other diseases.

Some of the research they mentioned has found that exercise also alters the molecular signaling inside other fat cells in a way that can improve insulin resistance, no matter what weight anyone has.

“Physical exercise seems to make fat better,” Dr. Gaesser said.

The main conclusion of the new review, he concluded, is that you should not lose weight to stay healthy. “You’d better, in terms of your risk of mortality, increase your physical activity and fitness than deliberately lose weight,” he said.