Effect of the volume of liquid food infused intragastrically on satiety in women

This experiment examined whether food volume and energy content affected satiety in lean and obese women, when visual and oral cues were bypassed by infusing food intragastrically. The effects of volume and energy content were examined separately by using liquid foods that differed in energy density (kcal/g). On 5 separate days, 25 lean and 29 obese women consumed all of their meals in the laboratory. A nasogastric tube was inserted 30 min before lunch on 4 days; on three of these occasions, a liquid preload was infused for 15 min and, on the fourth occasion (control), the preload was diverted covertly. On the remaining day, no tube was inserted. The three preloads varied two-fold in volume and energy content: 200 ml/200 kcal, 400 ml/200 kcal and 400 ml/400 kcal. The results showed that increasing the volume of infused food, but not the energy content, affected satiety in both lean and obese women. There was a mean decrease in energy intake at lunch of 77 kcal (13%) after the 400-ml preload compared with the iso-energetic 200-ml preload (P=.013). Increasing the energy content of infused food, but not the volume, did not affect satiety. Thus, when sensory cues were bypassed, the volume of liquid food infused intragastrically affected subsequent energy intake in both lean and obese women. These results suggest that gastric and postgastric mechanisms are involved in the effects of high-volume, low-energy-dense foods on satiety.