Story at a glance
- Many health recommendations are centered on weight loss.
- It’s difficult to study and compare different approaches to health maintenance without clinical trials.
- Researchers who examined previous studies found that focusing on physical activity rather than weight loss may be a better approach to reducing mortality risk.
When it comes to health, a lot of focus falls on losing weight and body mass index (BMI). Research focused on weight loss may find correlations to lower mortality risk, but a new paper suggests that more focus should be placed on physical activity rather than weight loss.
Shifting the goal away from weight loss could make more sense for people who are obese and want to be healthier.
“We would like people to know that fat can be fit, and that fit and healthy bodies come in all shapes and sizes,” said paper co-author Glenn Gaesser of the College of Health Solutions at Arizona State University in a press release. “We realize that in a weight-obsessed culture, it may be challenging for programs that are not focused on weight loss to gain traction. We're not necessarily against weight loss; we just think that it shouldn't be the primary criterion for judging the success of a lifestyle intervention program.”
In a paper published in iScience, researchers examine data from several studies that look at weight loss or physical activity, or a combination of the two. They propose a weight-neutral approach because a cardiorespiratory fitness or physical activity focused regimen reduces or eliminates mortality risk from being obese. They define weight-neutral as not focused on weight loss.
The authors write, “40-year trends in prevalence of obesity and weight loss attempts indicate that a weight-centric focus on obesity treatment has been largely ineffective.”
Regular exercise also improves cardiometabolic health, and that happens independently from weight loss.
By separating health from weight loss, the experts believe this would be a more effective way to improve health and reduce risk for people who are obese.
“This is especially important when you consider the physiological realities of obesity,” says co-author Siddhartha Angadi of the School of Education and Human Development at the University of Virginia in the press release. “Body weight is a highly heritable trait, and weight loss is associated with substantial metabolic alterations that ultimately thwart weight loss maintenance.”
One issue when it comes to studying this area of health is that some previous studies rely on epidemiological studies that cannot determine causes for obesity. These types of studies collecy various types of data that may be correlated with body weight, genetic factors or obesity. To fully examine a fitness-based approach to getting bodies to a healthy place would require randomized clinical trials with control groups and treatment groups, much like what is done for testing new drugs.
This group of researchers analyzed several of these studies to combine the data in a way that they could attempt to make larger conclusions.
“Collectively, however, these epidemiological studies demonstrate strong and consistent associations, and this is why meta-analyses can be useful,” Angadi said in the press release. “In the case of physical activity and fitness, the epidemiological evidence is supported by a large body of experimental studies and randomized controlled trials that have established plausible mechanisms for the consistent findings in epidemiological studies.”
The authors of the paper point out that recent fitness research suggests that focusing on physical activity and cardiorespiratory fitness reliably results in greater reduction of risk for mortality and heart disease. One study they cited found that in a study that followed up with people with coronary heart disease for more than 15 years, people who maintained at least low physical activity had 19 percent lower all-cause mortality risk than similar folks who were sedentary. People with high physical activity had even better results with 36 percent lower mortality risk. The authors also suggest that maintaining a physically active lifestyle may be more feasible than maintaining weight loss.
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