Previous studies indicated that physical characteristics of food influence satiety, but the relative importance of the oral, gastric, and intestinal behaviors of the food is unclear. The aim of this study was to investigate the satiating effects of 2 types of alginates, which gel weakly or strongly on exposure to acid, compared with guar gum whose viscosity is unaffected by acid. Subjects (n = 12; 3 men, 9 women) ingested a 325-mL sweetened, milk-based meal replacer beverage on 4 separate occasions, either alone as a control or including 1% by weight alginate or guar gum. Intragastric gelling, gastric emptying, and meal dilution were assessed by serial MRI while satiety was recorded for 4 h. MR images showed that all of the meals became heterogeneous in the stomach except for guar, which remained homogeneous. The alginate meals formed lumps in the stomach, with the strong-gelling alginate producing the largest volume. Although gastric emptying was similar for all 4 meals, the sense of fullness at the same gastric volume was significantly greater for all 3 viscous meals than for the control. Compared with the control meal, the strong-gelling alginate (P = 0.031) and guar (P = 0.041) meals increased fullness at 115 min, and the strong-gelling alginate decreased hunger by the 115-min (P = 0.041) and 240-min (P = 0.041) time points. Agents that gel on contact with acid may be useful additions to weight-reducing diets. We hypothesize that this effect is due to distension in the gastric antrum and/or altered transport of nutrients to the small intestine in the lumps.

Little is known about the factors influencing individual selection and consumption of fats or the role of sensory preferences in this process. Thirty human subjects kept diet records for 10 d and then underwent preference testing with fat-containing stimuli: 10 different foods, each prepared with 2–5 levels of fat. The mean preferred level of fat across all foods was used as an indicator of overall fat preference. Analyses indicate 1)wide individual variation in the most preferred fat level for each stimulus, with no consistent correlation among the various stimuli; 2)no consistent relationships among sensory and dietary measures; and 3)a positive correlation between overall fat preference and percent body fat (r = 0.46, P < 0.01). Although a battery of test stimuli may be used to identify individual and group sensory preferences for fats, relationships between sensory and dietary measures remain unclear.