Searching for individual multi-sensory fingerprints and their links with adiposity – New insights from meta-analyses and empirical data

The impact of cognitive distraction on gustatory perception in volunteers with obesity

Obesity, a global health challenge, is influenced by biological, behavioral, socioeconomical, and environmental factors. In our technology-driven world, distracted eating is prevalent, yet neurocognitive mechanisms behind it remain poorly understood. This study targets individuals with overweight and obesity, exploring taste perception under distraction comprehensively. Participants formed two distinct groups based on their Body Mass Index (BMI), lean and overweight/obese. During the experiment participants received gustatory stimuli while playing a Tetris game of various difficulty levels. Participants rated taste intensity and pleasantness, with linear mixed models analyzing distraction effects. Results confirmed that high distraction levels reduced perception of taste intensity (p = 0.017) and taste pleasantness (p = 0.022), with variations influenced by gender and weight status. Individuals in the overweight/obese group exhibited most profound intensity changes during distraction (p = 0.01). Taste sensitivity ratings positively correlated with BMI interacting with gender (male r = 0.227, p < 0.001; female r = 0.101, p < 0.001). Overall across both groups, female participants demonstrated higher taste sensitivity compared to male participants (p < 0.001). This study highlights the impact of cognitive distraction during consumption on taste perception, particularly in relation to weight status and gender, underscoring their significant roles in this interplay.

Orthonasal olfactory influences on consumer food behaviour

It is often suggested in the popular press that food chains deliberately introduce enticing product aromas into (and in the immediate vicinity of) their premises in order to attract customers. However, despite the widespread use of odours in the field of sensory marketing, laboratory research suggests that their effectiveness in modulating people's food behaviours depends on a range of contextual factors. Given the evidence that has been published to date, only under a subset of conditions is there likely to be a measurable effect of the presence of ambient odours on people's food attitudes and choices. This narrative historical review summarizes the various ways in which food odours appear to bias people's food preferences (appetite) and food choices (food consumption and purchase). Emphasis is placed on those experimental studies that have been designed to investigate how the characteristics of the olfactory stimuli (e.g., the congruency between the olfactory cues and the foods, intensity and duration of exposure to odours, and taste properties of odours) modulate the effects of olfactory cues on food behaviour. The review also explores the moderating roles of individual differences, such as dietary restraint, Body Mass Index (BMI), genetic and cultural differences in odour sensitivity and perception. Ultimately, following a review of empirical studies on food-related olfaction, current approaches in scent marketing are discussed and a research agenda is proposed to help encourage further studies on the effective application of scents in promoting healthy foods.

Evidence for an amodal domain-general object recognition ability

A general object recognition ability predicts performance across a variety of high-level visual tests, categories, and performance in haptic recognition. Does this ability extend to auditory recognition? Vision and haptics tap into similar representations of shape and texture. In contrast, features of auditory perception like pitch, timbre, or loudness do not readily translate into shape percepts related to edges, surfaces, or spatial arrangement of parts. We find that an auditory object recognition ability correlates highly with a visual object recognition ability after controlling for general intelligence, perceptual speed, low-level visual ability, and memory ability. Auditory object recognition was a stronger predictor of visual object recognition than all control measures across two experiments, even though those control variables were also tested visually. These results point towards a single high-level ability used in both vision and audition. Much work highlights how the integration of visual and auditory information is important in specific domains (e.g., speech, music), with evidence for some overlap of visual and auditory neural representations. Our results are the first to reveal a domain-general ability, o, that predicts object recognition performance in both visual and auditory tests. Because o is domain-general, it reveals mechanisms that apply across a wide range of situations, independent of experience and knowledge. As o is distinct from general intelligence, it is well positioned to potentially add predictive validity when explaining individual differences in a variety of tasks, above and beyond measures of common cognitive abilities like general intelligence and working memory.

Longitudinal study of energy, neurosensory and eating responses durinG pregnancY (ENERGY cohort): A study protocol

BACKGROUND AND AIMS

Physiological changes that occur during pregnancy can have long-term impacts on metabolism and neurosensory responses to food, which can impact nutrition and health outcomes. The ENERGY cohort is a longitudinal study that aims to capitalizes on pregnancy as a natural model of metabolic reprogramming in order to understand the neurosensory mechanisms underpinning links between metabolism and dietary behaviour. The study objectives are to test for multi-sensory shifts during pregnancy, and the effect of sensory changes on dietary choices and bodyweights, and to identify neurosensory mechanisms that determine macronutrient selection before and after pregnancy.

METHODS

A longitudinal cohort study involving 130 pregravid women planning to conceive with the next 12-months and 65 pregravid women with no short-term plans to conceive. Participants will be recruited from Dunedin and Auckland, New Zealand. The study will test for changes in diet, neurosensory outcomes, and metabolism across the reproductive cycle, from pre-pregnancy to 1-year post-pregnancy. Data will be collected at six timepoint throughout the pregnancy which will occur approximately every 3 months. The primary response variables will be changes in supra-threshold sensitivity across modalities, dietary intake, and metabolism between pre-pregnancy and post-pregnancy. Longitudinal data analysis will use linear mixed models to assess changes in the response outcomes over time adjusted for age, ethnicity, and socioeconomic status.

DISCUSSION

Understanding the relationship between metabolism, sensory processing, and macronutrient preferences will provide crucial insights into diet-related health issues, including obesity. This study will lead to the formation of a prospective research cohort that is unique to Aotearoa New Zealand, and will develop multidisciplinary skills that are increasingly necessary to addressing the obesity epidemic.

Olfactory and Gustatory Supra-Threshold Sensitivities Are Linked to Ad Libitum Snack Choice

Snacking is a common eating habit in the modern food environment. Individual snack choices vary substantially, with sweet versus savoury snacks linked to differential health outcomes. The role of olfactory and gustatory sensitivities in snack choices and consumption is yet to be tested. A total of 70 Caucasian young males (age: 21−39 years; BMI: 20.5−40.5 kg∙m−2) were tested for their supra-threshold sensitivities to sweet and savoury associated odours and tastants (vanillin, methional; sucrose, NaCl). The participants also attended an ad libitum task in which their intakes of sweet and savoury snacks were recorded and analysed. Univariate and multivariate analyses were used to test for relationships between odour/taste sensitivities and sweet versus savoury snack intake. Results indicated that individual sensitivities to sweet-associated stimuli (e.g., vanillin, sucrose) were negatively linked with intake of the congruent (e.g., sweet) snacks and positively linked with incongruent (e.g., savoury) snacks (p < 0.05). These differences were reflected by energy intake rather than consumption weight (p > 0.05). This study outlines the fundamental roles of olfactory and gustatory sensitivities in snack choices and offers novel insights into inter-individual variability in snack consumption.