Non food-related environmental stimuli induce increased meal intake in healthy women: comparison of television viewing versus listening to a recorded story in laboratory settings

The objective of the present study, performed under laboratory conditions, was to assess the impact of two non food-related environmental stimuli (television and auditory stimulus) on meal intake. Normal weight women (N=48) ate lunch in the laboratory once a week for four weeks. All lunches were identical and included popular traditional foods, of which participants could eat ad libitum. The first and last lunches were eaten in the absence of the environmental stimuli (control conditions); in the other two tests, presented in random order, subjects ate while either watching television or listening to a recorded story. Energy intakes were determined for each meal, as were ratings of hunger, satiety and meal palatability. Subjects filled out the Three Factor Eating Questionnaire at the end of the meal series. Meal size was significantly larger in the presence of both environmental stimuli than in both control conditions (+11.6%, 280 kJ, p<0.01). Television viewing induced a significant stimulation of intake, equal to, but not greater than the effect of the auditory stimulus. Ratings of hunger, satiety, and palatability were not significantly different between conditions, despite the differences in intake. These results suggest that environmental, non food-related stimuli could stimulate intake regardless of hunger-satiety or palatability conditions. Environmental stimulation of eating should be tested in other populations, eg subjects with weight control problems, and other conditions, e.g. free-living.