Blood glucose patterns and appetite in time-blinded humans: carbohydrate versus fat

We assessed the extent to which a possible synchronization between transient blood glucose declines and spontaneous meal initiation would lend support to the interpretation of a preload study with isoenergetic (1 MJ) isovolumetric high-fat or simple carbohydrate (CHO) preload drinks. Ten men (18-30 yr) fasted overnight and then were time blinded and made aware that they could request meals anytime. At first meal requests, volunteers consumed a preload; ad libitum meals were offered at subsequent requests. Postabsorptively, transient declines in blood glucose were associated with meal requests (chi(2) = 8.29). Subsequent meal requests occurred during "dynamic declines" in blood glucose after the peak induced by drink consumption (100%). These meal requests took twice as long to occur after high-fat than after CHO preloads (fat = 126 +/- 21, CHO = 65 +/- 15 min), consistent with differences in interpolated 65-min satiety scores (fat = 38 +/- 8.2, CHO = 16 +/- 4). Postprandially, transient blood glucose declines were associated with meal requests (chi(2) = 4.30). Spontaneous meal initiations were synchronized with transient and dynamic blood glucose declines. Synchronization of intermeal interval and dynamic declines related to higher satiating efficiency from high-fat preloads than from simple CHO preloads.