A study published in the International Journal of Obesity shows that children who are obese may overeat because they crave more sugar than slimmer children.
The researchers studied 23 children, ages 8–12, 10 of whom were obese and the others who were a normal weight. In the study the children were given a fifth of a teaspoon of water mixed with table sugar and asked to swirl it in the mouth with their eyes closed, while focusing on its taste.
They found neurons in the obese children's insular cortex and amygdala, regions of the brain involved in taste, motivation, and reward, were unusually lively when given the sugar water. Notably, they did not show any heightened brain cell ctivity in the striatum that is also part of the response and reward circuitry and whose activity has, in other studies, been associated with obesity in adults. But the striatum does not develop fully until adolescence.
The researchers believe that their scans document, for the first time, the early development of the food reward circuitry in young children. An elevated sense of "food reward" that involves being motivated by food and deriving a good feeling from it could mean some children have brain circuitries that predispose them to crave more sugar throughout life.