Psychophysics of sweet and fat perception in obesity: problems, solutions and new perspectives

Abstract

Psychophysical comparisons seem to show that obese individuals experience normal sweet and fat sensations, they like sweetness the same or less, but like fat more than the non-obese do. These psychophysical comparisons have been made using scales (visual analogue or category) that assume intensity labels (e.g. extremely) which denote the same absolute perceived intensity to all. In reality, the perceived intensities denoted by labels vary because they depend on experiences with the substances to be judged. This variation makes comparisons invalid. Valid comparisons can be made by asking the subjects to rate their sensory/hedonic experiences in contexts that are not related to the specific experiences of interest. Using this methodology, we present the evidence that the sensory and hedonic properties of sweet and fat vary with body mass index. The obese live in different orosensory and orohedonic worlds than do the non-obese; the obese experience reduced sweetness, which probably intensifies fat sensations, and the obese like both sweet and fat more than the non-obese do. Genetic variation as well as taste pathology contribute to these results. These psychophysical advances will impact experimental as well as clinical studies of obesity and other eating disorders.

Masticatory function, taste, and salivary flow in young healthy adults

“…According to the results of the third regression model, BMI and WC could explain 5% of taste. Obesity has been linked to diets containing high levels of fat and sugar, which may have implications for taste conditions (51,52); however, Donaldson et al (53) argued that taste is only one factor among the complex causes of obesity, which corroborates with the percentage of taste predicted in our results.…”

Changes in the salivary protein profile of morbidly obese women either previously subjected to bariatric surgery or not

“…These values comprehend background correction, which was applied for each band by normalising to an adjacent region of the membrane (b). Data are presented as mean ±SEM (*p <0.05, statistically significant differences) Changes in morbidly obese women's salivary proteome performed with regard to the subjects in this study, the high enzymatic activity observed in group O may provide support for the studies reporting low levels of sweet taste sensitivity combined with strong preferences for sweet foods in obese individuals [1]. Furthermore, the small quantities of this enzyme present following bariatric surgery may be related to potential recovery of sweet taste sensitivity which had already been reported for these individuals [4].…”

Salivary proteome and glucose levels are related with sweet taste sensitivity in young adults

“…As noted above, for salivary glucose results, higher levels of sweet molecules in saliva may mean a continuous stimulation of the taste receptors, requiring higher concentration of stimuli for sweet perception. The idea that a low sweet taste perception may be associated with higher levels of salivary amylase is, indirectly, supported by other observations: obese individuals, either rats [25] or humans [17], have increased levels of this salivary protein; at the same time, they appear to have higher preference levels for sweet foods, with the latter suggested as being associated with lower sensitivity to this taste [26].…”