The authors of a new study in the International Journal of Epidemiology have disproved the “fat but fit” concept after discovering that obesity cancels out the pros of being at high aerobic fitness.
Researchers at Umea University in Sweden were looking to find out whether negative health effects of obesity could be canceled out by high levels of fitness, UPI reports. Both were associated with death at older ages.
The study examined data on 1.3 million Swedish men followed from 1969 to 1996, with aerobic fitness measured by a braked cycle test (cycling until they had to stop) and causes of death tracked by Swedish national registers. The researchers concluded that based on a mean follow-up of 29 years, 44,301 people died, and men in the highest fifth of aerobic fitness showed a 48 percent lower risk of death from any cause, compared to those in the lowest fifth.
Stronger associations were observed for deaths related to suicide and alcohol abuse. But surprisingly, the authors noted a strong association between low aerobic fitness and deaths related to trauma.
Peter Nordstrom, the study’s co-author, said that there is not an explanation for this finding. “We could only speculate, but genetic factors could have influenced these associations given that aerobic fitness is under strong genetic control.”
When looking at the concept of “fat but fit is OK,” they found that men of a normal weight–regardless of their fitness level–were at a lower risk of death compared to obese individuals in the highest fourth of aerobic fitness. But, the relative benefits of high fitness levels could still be greater in obese people.
However, the beneficial effect of high aerobic fitness in this study was reduced with increased obesity. And those who had extreme obesity issues had no significant effects at all, according to Science 20.
Of course, the study only looked at men and relative early deaths. Nevertheless, authors say it disputes the concept of “fat but fit.”