Food reinforcement and eating: a multilevel analysis

Abstract

Eating represents a choice among many alternative behaviors. The purpose of this review is to provide an overview of how food reinforcement and behavioral choice theory are related to eating and to show how this theoretical approach may help organize research on eating from molecular genetics through treatment and prevention of obesity. Special emphasis is placed on how food reinforcement and behavioral choice theory are relevant to understanding excess energy intake and obesity and how they provide a framework for examining factors that may influence eating and are outside of those that may regulate energy homeostasis. Methods to measure food reinforcement are reviewed, along with factors that influence the reinforcing value of eating. Contributions of neuroscience and genetics to the study of food reinforcement are illustrated by using the example of dopamine. Implications of food reinforcement for obesity and positive energy balance are explored, with suggestions for novel approaches to obesity treatment based on the synthesis of behavioral and pharmacological approaches to food reinforcement.

Figure 1

Hypothetical demand curve for food. The Omax represents the maximal amount of responding for food, and the Pmax the behavioral price at which the greatest amount of responding is observed. As the behavioral cost to obtain food increases, responding increases up to an FR 1,000, and the relationship between behavioral cost and consumption is inelastic. After behavioral costs of FR 1,000 or greater, response rate decreases, and the relationship is elastic. The reduction in responding may be due to a combination of reinforcer satiation and the behavioral cost of obtaining the food. Adapted from a figure describing demand curves for drug reinforcers by Bickel and colleagues (Bickel et al., 2000).

Figure 2

Hypothetical examples of youths who substitute healthy foods for less healthy foods (left graph) or do not substitute healthy foods for less healthy foods (right graph) when the behavioral cost of obtaining the less healthy food is increased.