Obesity and thrifty genotype. Biological and social determinism versus free will.

Obesity is a global public health problem with a concerning increasing rate and no conclusive answer related to its causes. The thrifty genotype, proposed by James V. Neel in 1962, is one of the many hypotheses that intend to explain the epidemic. Neel proposed that genetic variations in hunter-gatherer communities-which were selectively favorable in the past since they allowed to confront famine-are currently a disadvantage because food is plentiful and relatively constant. This conclusion remains valid despite being highly criticized. This review discusses that the hypothesis of the thrifty genotype supports an explicative approach based on biological determinism. This approach, such as social determinism, underestimates the role of individuals as free entities responsible for their own behavior. While a drastic change in the current theoretical framework occurs, in which individuals are considered as independent, free and self-responsible agents with the ability to overcome their heredity and their environment, the idea that the obesity pandemic cannot be explained or solved will be present. Although the influence of these elements in behavior is not rejected, it is proposed that behavior potentially and mainly comes from free will, which is neither biologically nor socially determined.