In a cross-sectional cohort study, obese children and adolescents were less sensitive to salty, bitter, and umami (savory) tastes than those of normal weight, according to Susanna Wiegand, MD, of Charité Children's Hospital in Berlin, and colleagues.
There were no significant differences overall in the case of sweet and sour tastes, but obese participants consistently rated sweet samples as less sweet than did the normal-weight volunteers, Wiegand and colleagues reported online in Archives of Disease in Childhood.
Differences in taste perception may influence the rate of food consumption and thereby contribute to obesity, the researchers argued. But little is known about tastes other than bitter (the compound propylthiouracil), which has been the subject of a large number of studies in children and adolescents, they noted.
To help fill the gap, they enrolled 94 normal-weight (mean body mass index 18.2 kg/m2) and 99 obese (mean BMI 29.9 kg/m2) children and adolescents between 6 and 18, who were in good health and not taking any medications or suffering any diseases that affect taste and smell. The children were multi-ethnic and these obese participants came from the hospital's pediatric obesity center.
Each participant was tested using "taste strips" made of filter paper impregnated with each of the five taste sensations at four different levels of intensity, as well as two blank strips. They were asked to avoid eating or drinking anything other than water and to refrain from chewing gum for at least one hour before the tests.
In one experiment, all 22 taste strips were presented in increasing concentrations, but at each concentration the order of the tastes was varied randomly.
Participants got one point for each correct identification and the two blank strips were not included in the score, so a best-possible score was 20.
Total scores ranged between 2 and 19, Wiegand and colleagues reported, and the obese children and adolescents had an average score of 12.6, significantly lower than the 14.1 achieved by the control group.
There were no significant differences between the groups in the ability to identify sweet and sour, with average correct scores of 3.7 and 1.9, respectively, for each group.

On the other hand, the obese participants did significantly less well at identifying salty, umami, and bitter tastes.
In a separate experiment, participants were asked to rate the intensity of four different concentrations of sweet, Wiegand and colleagues reported.
Obese participants rated the lowest three concentrations as being less sweet than did members of the control group. The between-group differences were significant for the lowest concentration, for the next lowest, and for the third lowest. Only at the sweetest concentration did the groups agree.
Girls and older participants were better at picking out the right tastes, the researchers reported.
Wiegand and colleagues cautioned that the participants' socioeconomic status, which was not controlled for, could be a confounding factor, adding that 85 percent of the obesity cohort at their clinic has a low socioeconomic status. Also, there were differences in ethnicities and sex between the two cohorts. Finally, the cross-sectional study should be followed up by a longitudinal analysis.
Nonetheless, they concluded that the results "support the hypothesis that obese and non-obese children and adolescents differ in their taste perception," although exactly how remains a matter for investigation.
"Further studies on taste sensitivity and hormonal status in obese subjects are required [that might lead to] further strategies of obesity prevention and therapy in childhood," Wiegand and colleagues stated.