The science of childhood obesity

As scientists currently understand the phenomenon, widespread obesity represents an interaction of genes and the environment. Throughout human history, the ability to gain weight enabled humans to survive food shortages by tapping energy reserves stored in body fat. Today, an overabundance of calorie-rich foods enables calorie intakes that can overwhelm the body's weight-regulatory system. Genetic variation also makes some people more vulnerable than others to weight gain. Finally, there is a growing understanding of the deleterious biological and physiological consequences of accumulating too much fat.