Final answer:
Men in the Minnesota Starvation Study reduced their energy expenditure by decreasing physical activity, aligning with the body's adaptive mechanism of lowering basal metabolic rate to conserve energy during periods of reduced calorie intake.
Step-by-step explanation:
One way that men in the Minnesota Starvation Study reduced their energy expenditure was by decreasing physical activity. This approach is substantiated by the understanding that during periods of dietary restriction or fasting, the body adapts by reducing its basal metabolic rate (BMR) to conserve energy. Prolonged fasting or calorie reduction decreases metabolic rate due to the adaptive mechanisms the body engages in during times of scarcity.
In the study, men who were subjected to a reduced calorie intake experienced a drop in their BMR, making their bodies more efficient in using the limited energy available. To further reduce energy expenditure, they engaged in less physical activity, which also means that their bodies required less fuel to function. On the contrary, had they increased their physical activity, they would have expended more energy, which is not conducive to the goals of the study dealing with starvation conditions.