The men showed significant decreases in body weight and percentage of fat mass when measured with skin folds; the women experienced no change.

Statistically, the researchers calculated that 62.3% of this variation was explained by differences in fat free mass.

Both studies find that aerobic fitness levels do not improve the predictive power of fat free mass for resting metabolic rate.

Effects on body mass index, waist circumference or fat free mass were also not significantly different.

Lee et al. found no significant difference in the effect of this protein powder on fat mass compared with placebo.

This results in a loss of both fat and lean mass, leading to a significant reduction in total body weight.

PYY-knockout female mice increase in body weight and fat mass.

In mice, fat mass was reduced but livers enlarged and they became insulin-resistant.

Directly associated with enlarged fat mass is the chronic disease diabetes.

Nor does it distinguish between lean body mass and fat mass.