As obesity rates continue to rise, weight loss has become a central focus of health improvement strategies, often supported by various diet trends and weight-loss medications. However, a recent study published in the British Journal of Sports Medicine presents a compelling argument that challenges this conventional approach. The study suggests that cardiorespiratory fitness—rather than body mass index (BMI) or “fatness”—is a more significant factor in predicting disease risk and mortality.
Rethinking Health: Fitness vs. Fatness
The study analyzed data from 20 separate research projects, encompassing nearly 400,000 adults globally. Researchers found that fitness levels had a more substantial effect on reducing the risk of death, including from cardiovascular diseases, than BMI. In fact, individuals who were fit, regardless of their BMI, had similar mortality risks, while those who were unfit exhibited 2 to 3 times higher risks of death, regardless of their weight.
This finding runs counter to common assumptions, especially considering that the study reveals fit individuals with obesity had lower mortality risks than unfit individuals with a normal weight. Siddhartha Angadi, associate professor at the University of Virginia and corresponding author of the study, emphasized the study’s key takeaway: “Fitness, it turns out, is far more important than fatness when it comes to mortality risk.”
The Case for Cardiorespiratory Fitness
The research underscores the idea that exercise offers benefits beyond calorie burning. Regular physical activity positively impacts various bodily systems, improving overall health and reducing the risk of chronic diseases. Angadi pointed out that fit obese individuals had mortality risks comparable to those of fit individuals with a normal weight, and significantly lower risks than unfit individuals, regardless of their weight.
This finding challenges the conventional belief that weight loss is the primary means of improving health outcomes. While losing weight can offer benefits, it is notoriously difficult to sustain and often leads to “yo-yo dieting,” which carries its own health risks. Glenn Gaesser, co-author of the study, highlighted the dangers of weight cycling: “Most people who lose weight regain it. Repetitive cycles of losing and gaining weight—yo-yo dieting—are associated with numerous health risks comparable to those of obesity itself.”
Fitness Benefits for All Body Types
Cardiorespiratory fitness, commonly measured through VO2max during exercise stress tests, reflects how efficiently the body uses oxygen during physical activity. The study revealed that even modest increases in physical activity, such as brisk walking for 30 minutes a day, led to significant reductions in mortality risk, especially among sedentary individuals. For those in the lowest fitness percentile, small increases in physical activity resulted in the most substantial health benefits.
“The largest reduction in all-cause and cardiovascular disease mortality risk occurs when completely sedentary individuals increase their physical activity modestly,” said Angadi. This finding reinforces the idea that anyone, regardless of their current fitness level, can improve their health through physical activity.
Shifting the Focus to Fitness
The study’s authors argue that the time has come to reframe health strategies by prioritizing fitness improvement over weight loss. While obesity remains linked to various health issues, enhancing cardiorespiratory fitness could yield better outcomes without the potential harms associated with chronic dieting and weight regain. This approach may offer a more sustainable and enjoyable way to achieve better health—particularly for individuals who have struggled with weight loss.
Importantly, this research presents an urgent reminder for those who maintain a healthy weight but lead sedentary lives. It appears that physical activity should be a priority for everyone, regardless of weight, as fitness plays a crucial role in overall health and disease prevention.
Related Topics
