HIF1A and Obesity: Obesity is the result of the imbalance between high caloric intake and lack of energy expenditure, which leads to the constant expansion of adipose tissue, giving rise to hypertrophy and hyperplasia and causing greater permeability of adipose tissue to macrophages, where the lack of oxygen results in the activation of HIF-1α, which in turn is responsible for the activation of macrophages and the production of proinflammatory interleukins, giving way to low-grade chronic inflammation.