Herman Pontzer is an American evolutionary anthropologist at Duke University, where he is associate professor of evolutionary anthropology and global health. He is known for his research into human bioenergetics.
In the context of the exercise paradoxâÂÂwhere increased physical activity does not always lead to weight lossâÂÂPontzer helped develop a theory of human metabolism known as the "constrained daily energy expenditure model". According to this theory, total daily energy expenditure is not simply the sum of separate metabolic processes (such as basal metabolism, movement, digestion, reproduction, and immune function). Instead, energy expenditure increases with activity only up to a certain point, after which it . This suggests that humans have evolved a biological constraint that limits the total amount of energy expended per day.