A biologically preferred weight and body fat level. May not be the same as one"s preferred weight. The number of calories required to keep your body functioning at rest, also known as your metabolism. Resting metabolic rate, metabolic equivalent (term to express rmr) Age, genetics, weight, heredity, body fat percentage, gender, external temperature, Study in detail the physical and psychological effects of prolonged, famine-like semi-starvation on healthy men, as well as their subsequent rehabilitation from this condition. During the starvation period, the subjects received two meals per day designed to induce the same level of nutritional stress for each participant. Since each subject had distinct metabolic characteristics, the diet of each man was adjusted throughout the starvation period to produce roughly a 25% total weight loss over the 24-week period. The researchers tracked each subject"s weight as a function of time elapsed since the beginning of the starvation period.