Total Fasting and Total Fasting plus Exercise: Effects on Body Composition of the Rat

Abstract
The body weight of grossly obese rats was reduced by total fasting or by total fasting combined with exercise. Analyses were performed on the carcasses to identify the components of the body which were reduced in weight to account for the lower final body weight of the animals. The total fasted animals lost 345 ± 5 g in a period of 41 days. Exercise markedly accelerated the rate at which the starving animals lost weight, resulting in an average weight loss of 341 ± 30 g in a period of 27 days. The composition of the body substance lost by the total fasted animals was 6% protein, 56% fat, 38% water and less than 1% minerals, compared to 5% protein, 59% fat, 36% water, and less than 1% minerals for the total fasted plus exercised animals. The hearts of the total fasted or total fasted plus exercised animals were significantly reduced in size. The concentration of DNA (mg/g wet wt) was increased, but total DNA content was decreased, in the hearts of both groups.