Effects of learned flavor cues on single meal and daily food intake in humans.

This study examined the effects of learned flavor cues on lunch-meal and daily food intake in 39, normal-weight, free-living adults. Subjects were fed distinctly flavored high-calorie (HC) and low-calorie (LC) milkshake preloads. Following the repeated flavor-calorie pairings, the flavors of the milkshakes were covertly switched. Twenty-three percent of the participants were classified as sensory responders. That is, their lunch intake reflected the anticipated caloric content of the preloads based on the sensory properties rather than the true energy value. Short-term sensory learning did not reliably alter 24-h energy intake in these subjects. The remaining subjects (i.e., sensory nonresponders) ignored the flavor cues and consumed the same size lunches across all phases of the study. Compensation for the preloads was examined during the training period (i.e., before the flavors were switched). Sensory responders accurately adjusted lunch intakes on the first day of exposure to both preloads, demonstrating unlearned compensation for energy density. Compensation continued to be accurate across training days for the HC (85%) but not the LC preload (65%). Sensory nonresponders did not compensate accurately for either of the preloads. Thus, sensory responders were initially more responsive to the caloric density of the preloads and continued to make accurate adjustments when the flavor cue matched the caloric load (i.e., during training) but were misled by the flavor cue when it did not match the caloric consequence (i.e., when the flavors were switched). Sensory nonresponders ignored the sensory cues and ate the same size lunches regardless of the caloric value of the preload.(ABSTRACT TRUNCATED AT 250 WORDS)