Obesity and Genetics: What is the Connection?

Identifying the underlying causes of obesity can help equip us to more effectively treat this complex disease. Such insights may also benefit people living with obesity, since understanding the causes can ease some of the stigma and self-blame that sometimes accompany it. “It’s all in your genes” could provide a tidy explanation. It may also open opportunities for personalized medicine. However, genetics is only the start.

A growing body of evidence suggests that obesity is, in fact, genetic. Somewhere between 200 and 500 specific genes have been linked to the disease. Genes can influence things like how a person’s body stores fat, metabolizes nutrients, and signals feelings of fullness. Twin studies have supported the hypothesis that obesity is genetic. Several measures of obesity show a high rate of heritability, including BMI, waist-to-hip ratio, and skinfold thickness.

Whatever the role of genetics, there are typically additional factors at work. A combination of genetic and environmental factors influences body weight.

The Role of FTO in Obesity

One such gene is the fat mass and obesity-associated gene (FTO), which is found in up to 43% of the population. In the presence of readily accessible food, those with the fat mass and obesity-associated gene may have challenges limiting their caloric intake. The presence of this gene and other genes can cause:

• Increased hunger levels
• Increased caloric intake
• Reduced satiety
• Reduced control over eating
• Increased tendency to be sedentary
• Increased tendency to store body fat

The FTO allele allele associated with obesity is common in people with European ancestry, according to multiple studies and has been identified by genome-wide association studies (GWAS). It acts on a variety of biological and metabolic processes.

Researchers have taken a keen interest in FTO as a potential drug target for treating obesity. Several small molecule drugs and micronutrients have been found to control the expression or activity of FTO, thereby playing a role in regulating metabolism.