Obesity and the metabolic syndrome: impact of gene-diet interaction

Every disease susceptibility or medical condition is caused, regulated or influenced by genes and obesity is no exception. Although overeating in combination with low physical activity is the main cause of obesity, genetically determined influences on energy balance regulation also play an important role. Individuals exposed to the same environmental risk factors or treatment strategies do not necessarily develop the same disease or show the same reaction to treatment. Obesity forms the core element of a group of metabolic abnormalities defined as the metabolic syndrome, which underlies many chronic diseases of lifestyle treated by clinicians on a daily basis. The success of obesity prevention and treatment partly depends on the genetic make-up of the individual. Different genes may underlie different clinical outcomes due to interaction with diet as the main environmental factor. It is therefore important to know how certain genomic and lifestyle factors combine in different people to precipitate weight gain or weight regain. In future, genetic risk factors underlying different forms of obesity (e.g. morbid obesity, childhood obesity and weight retention after birth) could be identified as causative or contributing factors and possible targets for treatment. Alternatively, genetic testing can focus on a set number of genes involved in key metabolic pathways underlying different forms of obesity. This overview introduces the concept of pathology supported genetic testing in patients with the metabolic syndrome linked to a long-term health-outcome research project.