Do obese individuals gain weight more easily than nonobese individuals?

A review of studies done on human subjects who were overfed under controlled conditions for periods ranging from 2 to 12 wk shows that the energy cost of induced weight gain is a function of initial body weight and of lean body mass, body fat, and percent body fat. Therefore, bigger and fatter people need to eat more to gain a given amount of weight than do those who are thin. A likely explanation is that obese individuals tend to put on a large proportion of fat, a high-energy tissue, whereas thin people tend to gain more lean, which is a low-energy tissue.