The Current Obesity Epidemic: Unravelling the Evolutionary Legacy of Adipose Tissue

ABSTRACT

The evolution of organisms is shaped by the selective pressures to which they are subject. Selective pressures produce a trade-off between costs and benefits that ultimately influences the fitness of the whole organism. Classically, it has been pointed out that food intake is allocated between its use for physiological functions and its store for future utilization. Moreover, it is accepted that the perfect survivor must be able to eat and store as many calories as possible when food is available as a buffer against periods of scarcity. Thus, during evolution the ability to overeat and store the extra energy in specialized tissues has conferred an advantage. The strategy is known as the thrifty genotype (TG). The primary form in which chemical energy is stored in the body is fat. The aim of this article is to review the participation of adipose tissue in the TG. The role of fat within an evolutionary framework is explored. Moreover, the evolutionary purposes of the different adipose depots are analyzed, suggesting that each depot could have evolved in order to develop different functions. Finally, the contribution of the TG to the current obesity epidemic is questioned.