Effect of time of consumption of preloads on measures of satiety in healthy normal weight women

Differences in the time interval between preload and test meal may account for the variation in the satiating effects of whey protein found in previous preload studies. The objective was to compare the satiating effects (ad libitum meal intake at a set time after ingestion of preload) of whey protein (including glycomacropeptide) and maltodextrin carbohydrate and to determine whether such effects were influenced by the timing of preloads. On nine separate days, 19 healthy normal weight women consumed mixed composition preloads containing either water, or maltodextrin, or whey protein, 30, 60 or 120 min before an ad libitum test meal. Whey protein reduced food intake (p < 0.05) at the test meal more than maltodextrin and water (respective food energy intakes were 2343, 2584 and 3135 kJ). The time interval between preload and test meal did not affect the food intake response. Total energy intake (preload + test meal) differed, with intake for the maltodextrin-enriched preload being greater than that for the whey protein-enriched preload, which was greater than for the water control. Total respective energy intakes were 3955, 3676 and 3135 kJ. Subjective ratings of appetite did not support a greater satiating effect of whey protein versus maltodextrin on food intake but there was evidence for a satiating effect of maltodextrin and whey protein versus the water control.

• Variation between preload studies attributed to timing of preload and test meal.
• Satiety responses to different preloads at time delays of 30, 60 and 120 min.
• There was no influence of time delay on the effect of preload type on satiety.
• Whey protein increased satiety more than carbohydrate regardless of time delay.