A new editorial from three American cardiologists explains why that is such a big mistake.
Even if no visceral fat is burned, emerging evidence suggests physical activity can still improve the health and fitness of our hearts, thereby prolonging our lives.
When it comes to improving health, the cardiologists – Carl Lavie, Robert Ross, and Ian Neeland – argue that simply increasing the amount of physical activity is more important than focusing on weight loss.
The argument is contentious and will no doubt prompt further debate, but the authors clearly lay out their supporting evidence.
In particular, the cardiologists focus on a study published in the International Journal of Obesity in August that found measures of exercise are a much better predictor of long-term health than a person's body mass index or body fat content.
Among 116,228 adults, this study found increasing physical activity essentially eliminated most of the risk for all-cause mortality and cardiovascular-related deaths over the next 12 years.
This was true even if an individual's waist circumference increased during the same period.
"This is a finding that is entirely consistent with numerous observations demonstrating that exercise is associated with benefits across a wide range of health outcomes in association with no or minimal weight loss," the cardiologists write in their editorial.
"However, considerable evidence suggests that a monolithic focus on weight loss as the only determinant of success for strategies that aim to reduce obesity is not justified and, more importantly, eliminates opportunities to focus on other potentially important lifestyle behaviors that are associated with substantial health benefits."
In other words, doctors may be failing patients by putting too much emphasis on weight loss and not enough on decreasing sedentary behaviors.
While the editorial's authors acknowledge the "considerable and unequivocal evidence" that obesity is a health risk factor, they also point out an "obesity paradox", where obesity is sometimes associated with lower mortality risk.
In recent years, scientists from various fields have criticized modern medicine's narrow-minded view of obesity.
Last year, a 2021 review by two exercise physiologists argued for "a weight-neutral strategy" for obesity treatment.
Even when weight loss is not achieved, the 2021 review found exercise can improve most cardiometabolic risk markers associated with obesity. Weight loss, meanwhile, was not consistently associated with a lower risk of mortality.
In fact, one recent study among 10,000 patients with heart disease found that those with better cardiorespiratory fitness were more likely to survive the following 15 years, regardless of their BMI, body fat, or waist circumference.
"The finding that obesity and related health risks can be considerably reduced by adoption of a physically active lifestyle and a healthy diet, even in the presence of minimal weight loss, is encouraging and provides the practitioner and the adult with overweight/obesity additional options for successful treatment," the new editorial argues.
The editorial's authors have also investigated the matter. For instance, they mention an analysis Lavie conducted in 2018 that found changes in physical activity were a better predictor of both all-cause mortality and mortality specifically from cardiovascular disease. Weight loss, meanwhile, showed no such reduction in risk.
The evidence is stacking up, and it suggests that the relationship between physical activity, heart health, and fat loss is not as straightforward as many of us have been led to believe.
If a human is active enough, some experts think they should be considered healthy regardless of their weight.
Given how inconsistent weight loss and weight gain can be, these recent findings put more power in the hands of individuals.
If you want to feel fit and healthy, you might just need to get moving.
The editorial was published in the International Journal of Obesity.