Abstract
BACKGROUND: Price can influence food purchases, which can influence consumption. Limited laboratory research has assessed the effect of price changes on food purchases, and no research on individual differences that may interact with price to influence purchases exists. OBJECTIVE: We aimed to assess the influence of price changes of low-energy-density (LED) and high-energy-density (HED) foods on mother's food purchases in a laboratory food-purchasing analogue. DESIGN: Mothers were randomly assigned to price conditions in which the price of either LED or HED foods was manipulated from 75% to 125% of the reference purchase price, whereas the price of the alternative foods was kept at the reference value. Mothers completed purchases for 2 income levels ($15 or $30 per family member). RESULTS: Purchases were reduced when prices of LED (P < 0.01) and HED (P < 0.001) foods were increased. Maternal BMI interacted with price to influence purchases of HED foods when the price of HED foods increased (P = 0.016) and interacted with price to influence purchases of LED foods when the price of HED foods increased (P = 0.008). CONCLUSION: These results show the relevance of considering price change as a way to influence food purchases of LED compared with HED foods and the possibility that individual differences may influence the own-price elasticity of HED foods and substitution of LED for HED foods.