Increasing the portion size of a sandwich increases energy intake

This study investigated the effect on energy intake of increasing the portion size of a food served as a discrete unit. A within-subject design with repeated measures was used. The sample comprised 75 young adults (37 females and 38 males) from a university community. Individuals ate lunch in the lab once a week for 4 weeks. Each week, they were served one of four sizes of a deli-style sandwich (6, 8, 10, or 12 inches), of which they could eat as much as they wanted. Energy intakes were determined for each meal, as were ratings of hunger and satiety before and after each meal. A linear mixed model with repeated measures was used. The influence of subject characteristics was examined using analysis of covariance. The portion size of the sandwich significantly influenced lunch intake for both males and females ( P