Sex differences in reinforcing value of caffeinated beverages in adolescents.

Caffeine use is increasing among children and adolescents, but the effects of caffeine use on behavior and physiology within this population remain understudied and poorly understood. The purpose of this study was to test the hypothesis that adolescents find caffeinated soda more reinforcing than noncaffeinated soda and that this would be related to the level of usual caffeine consumption and to sex. We measured operant responding for portions of caffeinated and noncaffeinated soda at baseline and after daily consumption of 32 oz of caffeinated and noncaffeinated soda for 1 week each in 12-17-year-old participants.

Differential effects of daily snack food intake on the reinforcing value of food in obese and nonobese women.

Background: Food reinforcement, ie, motivation to obtain food, is associated with energy intake and obesity. Finding ways to decrease the reinforcing value of unhealthy foods may help with adherence to diets and maintenance of weight loss. Our previous study in nonobese adults showed that daily consumption of the same snack food (food consumed apart from meals) for 14 d significantly decreased its reinforcing value.