Tasting fat: Cephalic phase hormonal responses and food intake in restrained and unrestrained eaters

Abstract

Restrained eaters exhibit strict cognitive control over their food intake, primarily by limiting intake of high-fat foods. Earlier studies indicate a relationship between dietary restraint and cephalic phase insulin release, which is hypothesized to influence hunger and food intake. To compare cephalic phase hormonal responses to high- and low-fat stimuli and determine if the sensory experience of tasting fat alters hormonal responses and influences subsequent food intake in restrained and unrestrained eaters, normal weight women classified as unrestrained ( n = 11) or restrained ( n = 11) eaters were tested under 3 conditions: (1) fasting, (2) sham-feeding a non-fat cake, and (3) sham-feeding a high-fat cake. Following an overnight fast, arterialized venous blood was drawn prior to and for 30 min immediately following a 3-min sham feed. Plasma samples were analyzed for insulin, glucose, glucagon and pancreatic polypeptide (PP). Subjects were subsequently given a selection of high-fat and low-fat foods and allowed to select what they wished to eat. Cephalic phase PP was significantly greater following oral sensory stimulation by the high-fat food (205.4 ± 83.6) compared to the fasting control (11.1 ± 38.8, p = 0.04). No significant differences in hormonal responses to the food stimuli were found between restrained and unrestrained eaters but the restrained eaters consumed more food after the high-fat condition ( p < 0.05) relative to the fasted condition and compared to the unrestrained group ( p < 0.05). In conclusion, the sensory experience of tasting fat increases food intake in restrained eaters and increases vagal efferent activity compared to a non-fat food in both populations.