Perceptive, psychological and behavioural determinants of obesity

Taste acuity and psychological factors are determinants of food preference and consumption, but their role in the development of weight gain has been poorly investigated. The present study evaluated the relationship of overweight and obesity with taste perception and social, relational and emotional behaviour. One-hundred-twenty subjects with excess weight (BMI= 31.65.7 kg/m2) and 72 normal-weight subjects (BMI= 22.22.5 kg/m2) underwent the following experimental protocol: i) ambulatory evaluation of nutritional status with assessment of weight excess; ii) evaluation of taste acuity (bitter, salty, sour and sweet) by means of recognition thresholds measurement (3-AFC method); iii) psychographic-behavioural evaluation by means of a structured questionnaire consisting of 4 categories of questions (anxiety status, social integration, emotional status and eating disorder). Subjects differed in taste acuity: over-weight subjects had significantly higher recognition thresholds than normal-weight subjects for bitter (0.780.08 g/L vs 0.610.09 g/L; p<0.01), salty (9.012.96 g/L vs 3.192.26 g/L; p<0.01) and sweet tastes (15.933.82 g/L vs 8.842.35 g/L; p<0.01). No significant differences were found in taste acuity for sour taste. Questionnaire and thresholds data were submitted to Principal Component Analysis to investigate how overweight and normal-weight subjects were distributed in a multidimensional space as a function of the considered variables. As compared to normal-weight subjects, overweight/obese subjects were found to have a reduced taste acuity, a poor satisfaction of their profession, a poor degree of social integration and a high degree of anxiety. Reduced taste acuity is present in overweight and obese subjects and could contribute to weight gain in association to psychological factors.