Why Weight? Researchers Say It’s Fitness That Matters

It’s better to be fit than to be thin.

As obesity continues to climb in the United States, so have efforts to lose weight, fueling a new wave of weight-loss drugs. But University of Virginia researchers, working with colleagues from other schools, have found cardiorespiratory fitness is more important than obesity when it comes to living longer, healthier lives.

The researchers found that fit individuals shared similar risks of death and cardiovascular disease over the course of the study, no matter their weight. Fit individuals who are considered “obese” based on their body mass index had a significantly lower risk of death compared to people of normal weight who are not fit.

“Fitness, it turns out, is far more important than fatness when it comes to mortality risk,” said Siddhartha Angadi, associate professor of exercise physiology at the University of Virginia School of Education and Human Development and a corresponding author of the study. “Our study found that obese fit individuals had a risk of death that was similar to that of normal-weight, fit individuals and close to one-half that of normal-weight, unfit individuals.”

The study examined data from large epidemiological studies – research that looks at how diseases or health issues spread among groups of people. Researchers said the study indicates optimal health outcomes should be assessed based on the value of a fitness-based approach rather than a weight-loss approach in obese individuals.

“Exercise is more than just a way to expend calories. It is excellent ‘medicine’ to optimize overall health and can largely reduce the risk of cardiovascular disease and all-cause death for people of all sizes,” Angadi said.

The researchers reviewed 20 studies with a total sample size of 398,716 adults from multiple countries. About a third of the participants were female, nearly three times the number in previous studies. In most studies, individuals were classified as fit if their exercise stress test score placed them above the 20th percentile within their age group. 

“I believe this study will help strengthen the growing body of literature in the ‘fitness vs. fatness’ debate,” said Nathan Weeldryer, a doctoral student in kinesiology at UVA and co-author of the study. “As a society, we tend to equate body weight or fatness with health status. Our study, which features the largest and most globally representative sample to date, along with more rigorous statistical analysis compared to previous research, aims to shift perspectives on the relationship between fitness and body fat.

“While we still have a long way to go in changing the public’s views on health and body weight, I hope that studies like ours can contribute to a shift in attitudes,” he said.

Obesity is linked to a range of health conditions, and weight loss has long been seen as the way to reduce their impact. But weight loss is challenging and carries its own risks.