Fat brains, greedy genes, and parent power. A multi-disciplinary approach to child obesity

Abstract

The modern world is rife with opportunities to overeat – yet not everyone becomes obese. This could be because individuals differ in appetite-related traits that manifest early in development and predict weight trajectories. What determines these traits? Parental feeding studies generally show that restrictive feeding is linked with heightened appetite, and pressure to eat with reduced appetite. But these relationships reflect parents responding to children as well as vice versa. In fact, twin studies argue that nature, rather than nurture, is the largest contributor to child appetite, and behavioral investigations of obesity-associated variants arising from genome-wide association studies confirm the contribution of genes to eating behavior. Little is known about biological contributions to appetitive traits in humans, or how genetic and environmental influences interact at a biological level to influence appetite. However a number of brain imaging studies have investigated responses to food cues and intake in adults, children, and groups at high familial and/or genetic obesity risk, and results are so far consistent with the possibility that functional and structural variation in networks subserving motivation and control is associated with appetite and obesity, and shows genetic influence. The emerging biobehavioral susceptibility model provides a useful, inclusive framework for explaining child and adult obesity. It also suggests that prevention and treatment strategies should acknowledge the powerful contribution of genetic and biological influences to eating behavior, and focus on stimulus control as well as novel interventions to modify appetitive tendencies.