Obesity is considered one of the most troubling chronic diseases for public health because of its rapid growth in the population. Many are the causal factors of this epidemic, and in recent years studies suggest the involvement of genetic factors in the etiology of obesity as a risk factor for its development. Polymorphism of the FTO gene is being studied in the past eight years and has been indicated as a predictor of obesity in the population, as well as associations in food intake, raising the possibility of influence in the regulation of hunger and satiety. Accordingly, researchers observed changes in levels of postprandial leptin and ghrelin, which can promote appetite and change the quantity and quality of food intake in subjects with the polymorphism FTO.

Obesity is a chronic disease with high growth in the world population, as well as being a risk factor for the development of other chronic diseases. Additionally, it is known that it is a multifactorial disease and polygenic, making it difficult to control. It is also recognized that some environmental factors, with emphasis on diet, can modulate the expression of certain genes and may help control obesity.

In recent decades, researchers from several countries has been devoted to studies that aim to propose alternatives for the treatment of obesity, emphasizing the regulation of energy balance and changes in lifestyle (diet and exercise), and try to clarify the reason some individuals more susceptible to these factors than other, favoring the body weight gain. These differences may be explained in part, by genetic factors.

The FTO gene has been considered a strong candidate gene for obesity because of its relation to the secretion of ghrelin, an important orexigenic hormone involved in the regulation of food intake, which could open new perspectives for studies of gene-environment interactions in obesity.

Considering the significant increase of obesity in the world population, it is understood that studies assessing environmental factors - particularly diet - and genes and genetic variants associated with obesity - may represent a major breakthrough in understanding the development of this disease, providing tools to propose possible changes in current dietary prescriptions for this population.

Also highlighted the lack of studies on the subject, which makes this proposal is innovative and unprecedented as it aims to evaluate the relationship between the FTO gene polymorphism with ghrelin secretion and food intake in obese.

It is suggested that obese individuals with a polymorphism in the FTO gene present higher serum concentrations of basal ghrelin and postprandial (after-fat meal), and the usual food intake, as well as the postprandial appetite, are associated with the concentrations basal and postprandial ghrelin, respectively. These results may generate data for changes in dietary prescriptions aimed at reducing the secretion and, or sensitivity to the hormone to control energy intake, whereas the individual's genotype can not be changed voluntarily in the current state of the art.

Inclusion Criteria:

• Adult women with grade 3 obesity.

Exclusion Criteria:

• Pregnant women, teenagers, elderly, use of corticosteroids, medicines for weight loss, bariatric surgery and affected by chronic diseases, such as hyperthyroidism or hypothyroidism, nephropathy, neuropathy, and inflammatory bowel disease. Also excluded are volunteers who do not fulfill all stages of the study.