Delay Discounting, Reinforcing Value of Food, and Components of Metabolic Health

Background: According to the Centers for Disease Control and Prevention (CDC), over one-third of US adults are obese. In order to assess causes of and treatments for obesity, researchers have evaluated a number of processes underlying health-related behaviors, one of which is delay discounting. Delay discounting is a cognitive process that describes the phenomenon by which individuals discount the value of a future reward compared to the value of an immediate reward. Researchers have associated delay discounting with drug addiction, alcoholism, and cigarette smoking. More recently, delay discounting has been studied with regards to health-related behaviors, such as body weight management, food intake, glucose control, and physical activity. While a number of studies have concluded that obese individuals tend to be greater discounters, the relationship between delay discounting and various health-related behaviors beyond smoking and drug use remains unclear. The purpose of this study is to evaluate the relationship between delay discounting and diet quality, glucose tolerance, physical activity, and fasting vs. non-fasting conditions.

Methods: Sixty-five males (n=20) and females (n=45) were recruited for the present study. Participants completed two lab sessions: one under non-fasting conditions, and one under fasting conditions which involved measurements of body mass and composition, blood pressure, blood glucose, blood lipids, and health-related questionnaires. Delay discounting and food purchase tasks were completed at both visits. Participants were asked to complete a four-day food intake record and wear a physical activity monitor for four days.

Results: Lower rates of discounting were found in those who consumed more total vegetables, and lower food reinforcement was observed in those who spent less time sedentary and more time physically active, had greater dietary Restraint, and had a lower resting heart rate. There were no significant differences between discounting rates and food reinforcement across fasting and non-fasting conditions.