What constitutes food variety? Stimulus specificity of food.

Variety is a major influence of energy intake, but it is not known how much foods have to vary to influence eating. Using a stimulus specificity habituation paradigm we assessed the influence of varying the texture and appearance of nutritionally identical foods on responding for food and energy intake, and whether sensitization, or an increase in responding prior to habituation, was related to the rate of habituation or recovery of responding. Children responded for elbow macaroni and cheese until they habituated, then were provided either more elbow macaroni and cheese, spiral macaroni and cheese, or chicken nuggets. Children provided chicken nuggets or spiral macaroni and cheese recovered responding in comparison to more elbow macaroni and cheese. Children who sensitized showed slower habituation and consumed more food and more energy than those who did not sensitize, but did not differ in recovery of responding to the chicken nuggets or spiral macaroni and cheese. Results show small variations in food characteristics lead to recovery of responding and increased intake after children have habituated.

Variety influences habituation of motivated behavior for food and energy intake in children.

BACKGROUND: Research has shown that variety reduces the rate of habituation, or a general reduction in the rate of responding, for low-energy-density (LED) and high-energy-density (HED) foods. OBJECTIVE: We assessed whether the effects of variety on habituation of motivation to eat are different in overweight and lean children. DESIGN: Overweight and lean children (n = 84) were randomly assigned to groups that varied as to whether they received their favorite or a variety of LED or HED foods. RESULTS: Habituation was slower for overweight than for nonoverweight children (P = 0.008), for a variety of foods than for the same foods (P < 0.001), and for LED than for HED foods (P < 0.001). Energy intake was greater for overweight than for nonoverweight children provided with variety (P = 0.004) and was greater for overweight or nonoverweight children provided with the same food (P < 0.001). A variety of HED foods increased energy intake more than did the same HED foods (P < 0.001); this increase was greater than energy intake with the same or a variety of LED foods (P < 0.001). Children who sensitized, or showed an increase in responding before habituating, showed slower habituation (P < 0.001) and consumed more energy (P = 0.039) than did children who did not sensitize. CONCLUSIONS: Habituation is influenced by variety of foods, and overweight children increase energy intake more with variety than do leaner children. Research is needed to evaluate mechanisms of how variety influences the motivation to eat and energy intake, and how the variety effect can be used to influence intake across multiple eating occasions in children.