Soup and satiety.

Energy-yielding fluids generally have lower satiety value than solid foods. However, despite high water content, soups reportedly are satiating. The mechanisms contributing to this property have not been identified and were the focus of this study. A within-subject design, preload study was administered to 13 male and 18 female adults (23.7+/-0.9 years old) with a mean body mass index (BMI) of 23.0+/-0.7 kg/m2. At approximately weekly intervals, participants reported to the lab after an overnight fast and completed questionnaires on mood, appetite, psychological state, strength, and fine motor skills. After administration of motor tasks, participants consumed a 300-kcal preload in its entirety within 10 min. The test foods included isocaloric, solid, and liquefied versions of identical foods high in protein, fat, or carbohydrate. Single beverage and no-load responses were also tested. The same questionnaires and motor skills tests were completed at 15-min intervals for 1 h and at 30-min intervals for an additional 3 h after loading. Diet records were kept for the balance of the day. The soups led to reductions of hunger and increases of fullness that were comparable to the solid foods. The beverage had the weakest satiety effect. Daily energy intake tended to be lower on days of soup ingestion compared to the solid foods or no-load days and was highest with beverage consumption. Thus, these data support the high satiety value of soups. It is proposed that cognitive factors are likely responsible.