Being `lean and unfit` better than `fat and fit`

Washington D.C.: Challenging the conventional wisdom, a team of researchers has busted the myth that you can be "fat but fit."

In contrast, the results from the new study suggest that the protective effects of high fitness against early death are reduced in obese people.

This study by academics in Sweden followed 1,317,713 men for a median average of 29 years to examine the association between aerobic fitness and death later in life, as well as how obesity affected these results.

The subjects' aerobic fitness was tested by asking them to cycle until they had to stop due to fatigue.

Men in the highest fifth of aerobic fitness had a 48 per cent lower risk of death from any cause compared with those in the lowest fifth. Stronger associations were observed for deaths related to suicide and abuse of alcohol and narcotics. Unexpectedly, the authors noted a strong association between low aerobic fitness and also deaths related to trauma.

Co-author Peter Nordstrom has no 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."

With the limitation that the study cohort included only men, and relative early deaths, this data does not support the notion that 'fat but fit' is a benign condition.

The study appears in the International Journal of Epidemiology.