Objective: This study examined the impact of increasing beverage portion size on beverage and food intake.
Subjects: Thirty-three subjects, 18 women and 15 men, were included.
Intervention: In a crossover design, subjects consumed lunch in the laboratory once a week for 6 weeks. At each test lunch, the same foods were served, but the beverage served was varied in type (cola, diet cola, or water) and portion size (360 g/12 fl oz or 540 g/18 fl oz).
Main outcome measures: Beverage intake (g); energy intake from foods and beverages (kcal); and ratings of hunger, satiety, and characteristics of the foods and beverages served.
Results: Increasing beverage portion size significantly increased the weight of beverage consumed, regardless of the type of beverage served (P < 0.05). As a consequence, for the caloric beverage, energy intake from the beverage increased by 10% for women and 26% for men when there was a 50% increase in the portion served (P < 0.01). Food intake did not differ between conditions, so when the energy from the caloric beverage was added to the energy from food, total energy intake at lunch was increased significantly (P < 0.001) compared with noncaloric beverages.
Conclusions: Serving a larger portion of beverage resulted in increased beverage consumption, and increased energy intake from the beverage when a caloric beverage was served. Serving a caloric beverage resulted in an overall increase in total energy consumed at lunch. Therefore, replacing caloric beverages with low-calorie or noncaloric beverages can be an effective strategy for decreasing energy intake.