Study Finds Physical Activity, Not Weight Loss, Is Key to Reducing Health Risks

In the U.S., more than 7 out of 10 adults (73.6%) age 20 and over are overweight or obese, according to the latest data from the U.S. Centers for Disease Control and Prevention. (That percentage may sound shocking, until you realize those categorizations rely on the body mass index system.)

Many leading causes of death, including heart disease, are tied to an individual's weight. Recently, several researchers have been trying to determine to what extent this correlation is true—especially since nearly three-quarters of American adults are at risk.

Glenn Gaesser, Ph.D., a professor of exercise science at Arizona State University, describes the six stages of what he calls the "Weight Loss Futile Cycle" as (1) Desire to weigh less, (2) Weight loss attempts, (3) Failure to reach weight-loss goal or maintain weight loss, (4) Frustration and reduced adherence to weight-loss program, (5) Weight regain/overshoot, and (6) Obesity prevalence. And then there you are back at square one. Sound familiar?

"The weight-loss message is not, and has not been, working," Gaesser told WebMD in December. "The health benefits of exercise and diet are largely independent of weight loss."

In Gaesser's paper, "Obesity treatment: Weight loss versus increasing fitness and physical activity for reducing health risks," published in September 2021 in the journal iScience, he finds that "shifting the focus from weight loss to increasing physical activity and improving cardiorespiratory fitness" lowers the risk for death. Gaesser and his team believe that it's the healthier lifestyle choices many people make when attempting to lose weight, such as eating more fruits and vegetables and getting more exercise, that deliver a longevity boost—not necessarily carrying around less weight.

Previous studies have proven that ramping up physical activity lowers the risk of death from any cause by 15 to 50%. It also decreases the risk of heart disease by as much as 40%. The benefit of regular exercise is even more drastic when the activity improves your heart health (increasing circulation, lowering blood pressure, slowing your resting heart rate). Hopping from the least-fit to most-fit category can slash mortality risk by 30 to 60%, researchers say.

But, the benefits only stick around as long as the fitness routine stays in place.

"Adherence to exercise is just as challenging as adherence to diets. I think one of the reasons is that exercise has been promoted primarily as a means to lose weight," Gaesser said in the WebMD interview.

It's a constant battle for reasons in and out of our control. In a July 2021 review of 149 studies that involved exercise interventions of 2 weeks to 12 months, participants lost an average of 3 to 8 pounds. The human body isn't designed to like to lose weight, so it may slow the metabolism by about 28% in an attempt to make up for calories burned during exercise, an October 2021 study suggests. It can also increase appetite.

Being aware of the gap between anticipated and actual weight loss is important, according to Gaesser. Seeing a lower number on a scale is not a healthy goal; gaining fitness through an exercise regime suited to the individual is. Staring down at a scale can be discouraging. Eliminating that from a fitness routine may help those tempted to throw in the towel.

Gaesser's encouraging bottom line, according to his study: "Emphasizing the intrinsic value of [physical activity] and [cardiorespiratory fitness]—as primary outcomes—may avoid repeating 'failures' associated with a weight-centric approach."