Fat distribution in men of different waist girth, fitness level and exercise habit

Background: The risk of chronic disease is lower in obese men who are fit and active than obese men who are unfit and inactive. Methods/Objectives: Magnetic resonance imaging and spectroscopy were used to assess total and regional adipose tissue in 13 men who were slim, fit and active (the slim-fit), in 12 men who were slim, unfit and inactive (the slim-unfit), in 13 men who were fat, fit and active (the fat-fit) and in 12 men who were fat, unfit and inactive (the fat-unfit), in order to investigate the hypothesis that visceral fat and liver fat are lower in the fat-fit than the fat-unfit. Waist girth was used to distinguish slim men (<= 90 cm) and fat men (>= 100 cm). Maximal oxygen consumption was used to identify fit men (above average for age) and unfit men ( average or below for age). Fit men reported at least 60 min of vigorous aerobic activity per week and unfit men reported no regular moderate or vigorous activity in the last 2 years. Results: Total fat was not significantly different in the slim-fit and the slim unfit, but the proportion of internal fat was significantly lower (P<0.05) and the proportion of visceral fat was almost significantly lower (P-0.06) in the slim-fit than all other groups. Total fat was not significantly different in the fat-fit and the fat-unfit, but visceral fat and liver fat were significantly lower in the fat-fit than the fat-unfit (P<0.01). Waist girth and years of exercise explained 84% of the variance in total fat, waist girth and maximal oxygen consumption explained 70% of the variance in visceral fat, and waist girth alone explained 25% of the variance in liver fat. Conclusion: Chronic disease risk may be lower because visceral fat and liver fat are lower in men who are fat, fit and active. International Journal of Obesity (2009) 33, 1356-1362; doi: 10.1038/ijo.2009.189; published online 15 September 2009