As greater food variety has been shown to increase intake and is associated with a higher BMI, interventions that modify the effects of food variety have implications for combatting obesity. Previous research has shown that labelling a food with ‘high variety’ flavour-specific labels can reduce an individual’s satiation whilst eating. We were interested in whether the effects of ‘variety labelling’ would also be observed on portion size selection and ad libitum food intake. Therefore, two studies were conducted to explore the effects of labelling foods with different levels of variety on ideal portion size, ratings of expected fullness, and actual intake. In Study 1 (N = 294), participants viewed images of a range of foods that were presented with either high variety labels (descriptions of within-food components), low variety labels (general names of food items), or no label. They selected their ideal portion size and rated their expected fullness for each food. In Study 2 (N = 99), they also consumed one of these foods ad libitum. It was hypothesised that foods presented with high variety labels would have an increased ideal portion size, reduced expected fullness, and increased intake compared to foods presented with low variety labels or no label. Our findings failed to support these predictions, and we found no evidence of an effect of variety labelling on ideal portion size, expected fullness or food intake. These findings highlight the importance of considering how consumer research studies translate to a more ‘real world’ setting.

Portion size is known to be a key driver of food intake. As consumed portions are often pre-planned, ‘ideal portion size’ – an individual’s preferred meal size selected prior to eating – has been identified as a strong predictor of actual consumption. However, assessments of ideal portion size have predominantly relied on laboratory-based computer tasks, limiting use online. Therefore, this study sought to pilot test the validity of a web-based tool to measure ideal portion size. In an online study (N = 48), participants responded to images of a range of foods. Each food was photographed in a series of different portions, and loaded into an ‘image carousel’ that would allow participants to change the size of the displayed portion by moving a slider left-to-right. Using this image carousel, participants selected their ideal portion size. They also completed measures of expected satiety and expected satiation, and self-reported their age and body mass index (BMI). A non-parametric correlation matrix was used to explore associations between ideal portion size and identified predictors of food intake. Supporting convergent validity of this measure, ideal portion size was significantly correlated with expected satiety and expected satiation (after controlling for effects of baseline hunger and fullness), consistent with past research. Similarly, supporting divergent validity of this measure, ideal portion size was not significantly correlated with age or BMI. Pilot results support the validity of this web-based tool to measure ideal portion size, though further research is needed to validate use with comparisons to actual food intake.

Previous research has suggested that differences in psychological traits and eating behaviours may characterise groups of individuals with similar weight management profiles, for example, individuals who have successfully maintained a significant weight loss compared to those who have not. However, studies have tended to rely on arbitrary thresholds to group individuals, which may have biased findings. Across two studies, we sought to identify and validate weight management profiles using a clustering approach (i.e., without pre-defined grouping thresholds) and to examine differences across groups in terms of psychological and eating behaviour traits. Data were collected using online questionnaires (Study 1 was a secondary data analysis and study 2 was a primary data analysis that also allowed for cluster validation). Cluster analysis was implemented with BMI, diet history, weight suppression (difference between highest and current weight) as primary grouping variables, and age and gender as covariates. Differences in psychological and eating behaviour traits (e.g., impulsivity and restraint) were explored across clusters. In study 1, 423 participants (27.21 ± 9.90 years) were grouped into 5 clusters: lean men, lean women, lean middle-aged women, successful and unsuccessful dieters. The cluster structure was broadly replicated in study 2 with 368 participants (34.41 ± 13.63 years). In both studies, unsuccessful dieters had higher restrained and emotional eating scores than lean individuals, and in study 1, they also had higher food addiction scores than successful dieters. Individuals could be meaningfully grouped in terms of their weight management profiles and differences in psychological and eating behaviour traits were evident across these groups. Findings are in line with existing theory (e.g., Lowe's three factor model of dieting) but longitudinal research is needed to determine directionality between weight management profiles and relevant traits in order to inform future targeted interventions.