Behavioral and perceptive determinants of obesity in italian adults

The causes that led to the increase of obesity are of different nature: cultural, economic, biological and epidemiological. None of the above causes has been shown to play a priority role in weight increase. Recent evidence has suggested that factors related to sensory perception may explain weigh excess but the results are rather contradictory and not easy to compare. The aim of the present study was to compare taste sensitivity in normal weight (NW) and obese (OB) subjects and verify whether Body Mass Index (BMI)-related differences in thresholds may explain variation in food liking and food neophobia. Taste thresholds sensitivity of the 4 basic tastes (sweet, salty, sour and bitter) and the threshold of fat stimulus were measured by 3-alternative forced choice procedure. The density of fungiform papillae (FP) in relation to the nutritional status was also evaluated. Fifty-one OB subjects (BMI= 21.57 ± 1.95) and fifty-two healthy NW subjects (BMI= 34.08 ± 4.29) were recruited. Results revealed that OB subjects have significantly (p<0.05) higher threshold values for all the stimuli, as well as for fat sensation, and a reduced number of FP than NW. Hence, OB subjects seem to be less sensitive to tastants than NW and this may lead them to eat more sweet or savory food in order to compensate their reduced sensitivity. No significant association was observed between food neophobia and BMI. Mean hedonic ratings for “low energy dense” products did not vary according to BMI whereas, OB subjects showed significantly (p<0.01) higher liking for “high energy dense” products than NW controls. In conclusion, the relation between the responsiveness to taste stimuli and weight status, that is not yet well understood, seem to play a pivotal role to understand factors influencing or leading to obesity.