Effects of food form and timing of ingestion on appetite and energy intake in lean young adults and in young adults with obesity.

OBJECTIVE Overweight and obesity have been attributed to increased eating frequency and the size of eating events. This study explored the influence of the timing of eating events and food form on appetite and daily energy intake. DESIGN Crossover, clinical intervention where participants consumed 300-kcal loads of a solid (apple), semisolid (apple sauce), and beverage (apple juice) at a meal or 2 hours later (snack). SUBJECTS Twenty normal-weight (body mass index 22.6+/-1.8) and 20 obese (body mass index 32.3+/-1.5) adults. There were 10 men and 10 women within each body mass index group. MEASUREMENTS On six occasions, participants reported to the laboratory at their customary midday mealtime. Appetite questionnaires and motor skills tests were completed upon arrival and at 30-minute intervals for the 2 hours participants were in the laboratory and at 30-minute intervals for 4 hours after leaving the laboratory. Diet recalls were collected the next day. Data were collected between January 2006 and March 2007. RESULTS Whether consumed with a meal or alone as a snack, the beverage elicited the weakest appetitive response, the solid food form elicited the strongest appetitive response and the semisolid response was intermediate. The appetite shift was greatest for the solid food when consumed as a snack. The interval between test food consumption and the first spontaneous eating event >100 kcal was shortest for the beverage. No significant treatment effects were observed for test day energy intake or between lean individuals and individuals with obesity. CONCLUSIONS Based on the appetitive findings, consumption of an energy-yielding beverage either with a meal or as a snack poses a greater risk for promoting positive energy than macronutrient-matched semisolid or solid foods consumed at these times.