Non-Conscious Effect of Food Odors on Children’s Food Choices Varies by Weight Status

Abstract

ObjectiveFood cues are omnipresent in the daily environment and may influence eating behavior even non-consciously. An increased reactivity to food cues, such as food odors, has been shown to be correlated with obesity in children. The objective of this study is to investigate whether the non-conscious influence of food odors on children’s food choices varies by their weight status.MethodsSeventy-four children, of whom 29 were obese, took part in this study. The children performed a food choice intention task presented as a computer game in which 30 pairs of food images (a fatty-sweet food picture vs. a fruit picture) successively appeared on the screen. The children had to choose the item “they most wanted to eat at the present moment” for each pair. While performing this task, the children wore a headset in which the microphone foam was odorized with a fruity odor, a fatty-sweet odor or no odor. They performed the intention task three times, one time for each olfactory condition. The odors were non-attentively perceived, i.e., none of the children were aware of the odorization of the microphone foams. The modeled probability is the probability to choose a fruit.ResultsIn children with obesity, the fruity odor increased the likelihood of a fruit to be chosen compared to the no-odor condition [OR (95% CL) = 1.42 (1.13–1.78), P = 0.0028], while the fatty-sweet odor had no effect on food choice [OR (95% CL) = 1.07 (0.85–1.36), P = 0.55]. In children without obesity, both the fruity and the fatty-sweet odors decreased the likelihood to choose a fruit compared to the no-odor condition [OR (95% CL) = 0.76 (0.64–0.90), P = 0.0015, for the fruity odor and OR (95% CL) = 0.79 (0.66–0.93), P = 0.0062, for the fatty-sweet odor].ConclusionThe different patterns of results obtained in both groups of children suggest differences in the mental representations activated by non-attentively perceived olfactory cues based on weight status.

Implicit food odour priming effects on reactivity and inhibitory control towards foods

“…In an earlier study, we found that implicit priming of olfactory food cues had differentiated effects: individuals with obesity were more vulnerable to a non-attentively perceived pound cake odour in their bottom-up processing of food cues [23]. For individuals with overweight in the present study, the effect of the pear odour is consistent with a study by Marty & al [19] in which olfactory pear and pound cake primes had differentiated effects when they were non-attentively perceived by children with overweight. Indeed, these children were more prone to choose fruit in a forced-choice task when they were non-attentively primed with a pear odour.…”

“…The result of the priming effect seen here is congruent with the results of previous studies [19,23]. In an earlier study, we found that implicit priming of olfactory food cues had differentiated effects: individuals with obesity were more vulnerable to a non-attentively perceived pound cake odour in their bottom-up processing of food cues [23].…”

“…In order to non-attentively expose participants to olfactory food cues, we used the olfactory priming paradigm developed by Marty & al. in 2017 [19,23]. In this paradigm, participants perform three identical blocks of a computerized task (here, the modified Affective Shifting Task) while wearing a headset with a microphone.…”

“…Indeed, olfaction is strongly tied to food intake as food odours generally signal food availability [18]. Several studies have shown that food odour priming might modify several aspects of eating behaviour, such as attitudes to foods [19], food choices [20], food intake [21,22], and bottom-up cognitive processing of food stimuli [23].…”

Eating and Drinking in Childhood

“…In other words, it may be possible to orientate children's food choices by making choice option more or less salient in children's mind, by manipulating cues in the environment that are likely to "prime" mental representation of these foods (Chambaron et al 2015;Gaillet et al 2013). Following on this idea, one study attempted to prime mental representations of healthy versus unhealthy foods in children by using olfactory primes (respectively, a pear odor to prime "healthy foods" and a pound cake odor to prime "unhealthy foods") and evaluated whether the presence of these olfactory primes would be associated with different choices for healthy versus unhealthy foods and whether the effect of the olfactory primes on food choices would be different in children with or without overweight (Marty et al 2017a). In children with obesity, the fruity odor increased the likelihood of a fruit to be chosen compared to the noodor condition, while the fatty-sweet odor had no effect on food choice.…”