Increasing the volume of a food by incorporating air affects satiety in men

Previous research indicated that increasing the volume of food by adding water can lead to reductions in energy intake. However, the addition of water affects not only the volume but also the energy density (kJ/g) of foods. No studies have examined the effect of volume independent of energy density on intake. We examined the effect of food volume independent of energy density on satiety. In a within-subjects design, 28 lean men consumed breakfast, lunch, and dinner in the laboratory 1 d/wk for 4 wk. On 3 d, participants received a preload 30 min before lunch and on 1 d no preload was served. Preloads consisted of isoenergetic (2088 kJ), yogurt-based milk shakes that varied in volume (300, 450, and 600 mL) as a result of the incorporation of different amounts of air. Preloads contained identical ingredients and weighed the same. The volume of the milk shake significantly affected energy intake at lunch (P < 0.04) such that intake was 12% lower after the 600-mL preload (2966 +/- 247 kJ) than after the 300-mL preload (3368 +/- 197 kJ). Subjects also reported greater reductions in hunger and greater increases in fullness after consumption of both the 450- and 600-mL preloads than after the 300-mL preload. Changing the volume of a preload by incorporating air affected energy intake. Thus, the volume of a preload independent of its energy density can influence satiety.