Genetics of obesity: gene x nutrient interactions.

Obesity results from a long-term positive energy balance, in which gene-related differences may account for some of the disparities found in weight gain among populations. However, the rising prevalence of obesity in developed and developing societies must reflect lifestyle changes. Despite that the genetic background remains stable over many generations, obesity may be derived from a failure on the homeostasis systems, as a consequence of a dysfunction at the genetic level, which may be affected by changing environmental exposure (dietary habits, sedentarism, etc). In practice, obesity risk at least depends on two important factors, which mutually interact: 1) genetic variants and gene expression changes in candidate genes and 2) exposure to environmental risk factors. Disagreements among studies involving gene-nutrient interactions may reflect the difficulty of accurate measurement of specific types of dietary macro and micronutrients intake as well of phenotype assessment rather than a discrepancy in biological relevance. Identification of individuals who are genetically more likely to respond to particular dietary changes may be important for successful intervention in obesity treatment, since gene screening will allow health professionals to tailor-design weight management and dietary guidance in individuals with a genetic predisposition to become obese.