Interaction between genes involved in energy intake regulation and diet in obesity

Obesity is a multifactorial, complex, and public health problem worldwide. Interaction between genes and environment as associated with diet may predispose an individual to obesity. In this sense, nutrigenetics appears to be a strategy that can improve understanding of the gene-diet interaction. The aim of this literature review was to summarize data from studies of genes involved in the regulation of energy intake (melanocortin 4 receptor [MC4R], fat mass and obesity-associated [FTO], ghrelin [GHRL], leptin [LEP], and cholecystokinin [CCK]) and diet interaction in obesity. The presence of polymorphisms in MC4R, FTO, leptin, and the respective receptor appear to be associated with higher energy and total lipid consumption. Polymorphisms in FTO, leptin, and leptin receptor are also related to increased intake of saturated fatty acids. Individuals with the MC4R, FTO, and ghrelin polymorphisms, who submitted themselves for weight loss intervention, appeared to achieve weight loss similar to individuals without polymorphisms in these genes. Additionally, protein seems to interact with these genes, which increases or decreases appetite, or to drive or lessen body weight recovery. Additionally, polymorphisms in these genes were found to be associated with inappropriate eating behaviors, such as increased consumption of sweets and snacks, consumption of large food portions, desire to eat, and eating associated with emotional issues. Preliminary data has supported the gene-diet interaction in determining weight loss and gain in individuals with polymorphisms in the genes involved in energy intake. Despite the advent of nutrigenetics in obesity, it is still too early to define the dietary management for weight loss based on the presence or absence of obesity polymorphisms.