Rethinking obesity: New study highlights the true key to health

A new study published in the British Journal of Sports Medicine challenges the prevailing focus on weight loss as the primary strategy for improving health outcomes.

The findings reveal that cardiorespiratory fitness is a more reliable predictor of mortality risk than body mass index (BMI), underscoring the critical role of physical activity in overall health, regardless of body size.

The meta-analysis reviewed 20 studies, encompassing nearly 400,000 participants from diverse backgrounds, and found that individuals with higher fitness levels had significantly lower risks of cardiovascular disease and all-cause mortality, regardless of their BMI category. Fit individuals, even those classified as living with overweight or obese, exhibited mortality risks comparable to their normal-weight fit counterparts.

In contrast, unfit individuals across all weight categories faced a two-to threefold increase in mortality risk compared to fit individuals. Notably, obese but fit participants had better health outcomes than normal-weight individuals who were unfit.

“Fitness is far more important than fatness when it comes to reducing mortality risk,” said Siddhartha Angadi, associate professor of exercise physiology at the University of Virginia and the study's corresponding author. “Exercise isn’t just about burning calories, it’s a potent form of medicine that can significantly lower health risks for people of all sizes.”

The study also highlighted the potential harms of weight cycling, or “yo-yo dieting,” where individuals repeatedly lose and regain weight. Glenn Gaesser, professor at Arizona State University and a co-author of the study, explained; “Weight cycling is associated with health risks comparable to obesity itself. Improving fitness offers a sustainable and effective alternative to mitigate these risks.”

Physical activity guidelines recommend at least 150 minutes of moderate-intensity exercise weekly, such as brisk walking, and strength training twice a week. The research underscores that even modest increases in activity levels, such as walking 30 minutes a day, can deliver significant health benefits, especially for sedentary individuals.

As rates of obesity rise, the study calls for a shift in focus from weight-loss strategies to a fitness-centered approach. It emphasises that enhancing cardiorespiratory fitness can optimise health outcomes and reduce mortality risks without the challenges and potential setbacks associated with sustained weight loss.