Children who are overweight and obese eat 34% more calories from snack foods even after eating a meal, compared to their siblings of average weight.

Indulging in that much more food, if continued over time, can lead to excess weight gain, according a study from the University of Pennsylvania School of Nursing in The American Journal of Clinical Nutrition.

Bodyweight has increasingly become a huge health issue in the United States. Just over one third of Americans are of normal weight, while 35.8% are overweight and 27.6% are obese.

In the study, consisting of 47 same-sex sibling pairs, results showed that overweight and obese kids were more susceptible than their normal-weight siblings to overeating when shown tasty snacks after eating meals they had enjoyed until they felt full.

When given a calorie-dense appetizer before dinner time, the average-weight siblings ate less of their dinner than their overweight brother or sister. Meanwhile, the obese and overweight siblings did not lessen the amount of food they consumed at dinner enough to offset the extra calories they picked up from the appetizer.

Tanja Kral, Ph.D., head author and an assistant professor at Penn Nursing explained:

“The overweight and obese siblings showed an impaired ability to adjust for calorie differences and consumed more snacks even when satiated. These findings suggest some children are less responsive to their internal cues of hunger and fullness and will continue eating even when full.”

Dr. Kral pointed out that this inability might be hereditary, and then made worse by an environment that serves big portions of unhealthy foods. Since the full siblings had more similar eating patterns than the half-siblings, the expert suggests that genetics is playing a role.

The subjects were analyzed for three weeks, while once a week they were given a pasta dinner with tomato sauce, broccoli, unsweetened applesauce, and two percent milk.

The overweight and obese kids ate an average of 93 calories more than their normal-weight siblings when given the option to eat delectable snacks after their meal. Over time, this additional calorie intake is actually enough to cause excess weight gain.

Dr. Kral concluded:

“These findings may represent a behavioral inclination for obesity in children. Future studies should test whether teaching children to focus on internal satiety cues and structuring the home food environment in a healthy way may prevent at-risk children from overeating.”

Written by Sarah Glynn