The energy density of weight loss in semistarvation

The energy density of weight loss in semistarvation has been calculated using the two-reservoir energy model and has been found to be 4436 +/- 869 kcal/kg (18.57 +/- 3.60 MJ/kg). For the first 12 weeks of the semistarvation period, the coefficient of variation was 0.19 indicating that the energy density was reasonably constant. The value reported here is considerably less than the commonly accepted value. Calculation of the energy density of the change in the lean body mass shows a general decline in value which we attribute to a decrease in the rate of protein catabolism. The initial protein loss rate was 0.48 +/- 0.12 kg/wk while the average protein loss rate for the second 6 weeks of semistarvation was found to be 0.12 +/- 0.03 kg/week. It is also shown that the response time of the lean body mass decrease was 64 +/- 2 days while that of the fat store decrease was 135 +/- 4 days.