Comparing body composition between the sweet-liking phenotypes: experimental data, systematic review and individual participant data meta-analysis

Abstract

Background: Legislation aimed at reducing sugar intake assumes that sweet-liking drives overconsumption. However, evidence that a greater liking for sweet taste is associated with unhealthier body size is mixed and complicated by relatively small samples, an overreliance on body mass index (BMI) and lack of classification using sweet-liking phenotypes.

Methods: We first examined body size data in two larger samples with sweet-liking phenotyping: extreme sweet-likers, moderate sweet-likers and sweet-dislikers. Adults (18-34yrs), attended a two-session lab-based experiment involving phenotyping for sweet-liking status and a bioelectrical impedance body composition measurement (Experiment One: N = 200; Experiment Two: N = 314). Secondly, we conducted an individual participant data (IPD) meta-analysis: systematic searches across four databases identified 5736 potential articles. Of these, 53 papers met our search criteria: a taste assessment that measured liking using sucrose (>13.7% w/v), which allowed sweet-liking phenotyping and included either BMI, body fat percentage (BF%), fat-free mass (FFM) or waist-circumference.

Results: A significant effect of sweet-liking phenotype on FFM was found in both Experiment One and Two, with extreme sweet-likers having significantly higher FFM than sweet-dislikers. In Experiment One, sweet-dislikers had a significantly higher BF% than extreme sweet-likers and moderate sweet-likers. However, as these data are from one research group in a young, predominantly westernised population, and the results did not perfectly replicate, we conducted the IPD meta-analyses to further clarify the findings. Robust one-stage IPD meta-analyses of 15 studies controlling for sex revealed no significant differences in BF% (n = 1836) or waist-circumference (n = 706). For BMI (n = 2368), moderate sweet-likers had slightly lower BMI than extreme sweet-likers, who had the highest overall BMI. Most interestingly, for FFM (n = 768), moderate sweet-likers and sweet-dislikers showed significantly lower FFM than extreme sweet-likers.

Conclusion: The higher BMI often seen in sweet-likers may be due to a larger FFM and questions the simple model where sweet liking alone is a risk factor for obesity.

Fig. 1. Liking patterns for the three sweet-liking phenotypes defined by hierarchal cluster analysis.

Modified with permission from [23], this figure shows the differential liking patterns for the three sweet-liking phenotypes as categorised by hierarchal cluster analysis: Extreme sweet-likers (ESL), whose liking increased with sweetness intensity; Moderate sweet-likers (MSL), whose liking peaked at around 0.25 M sucrose before decreasing; and sweet-dislikers (SD), whose liking decreased with sweetness intensity. See [23] for analysis of the sensitivity and specificity scores in deciding phenotype cut-offs dependent on sucrose concentration.

Fig. 2. Individual participant data PRISMA flow diagram.

The IPD PRISMA flow diagram indicating the number of studies retained and excluded at each stage of the review process.

Fig. 3. A comparison of the four key anthropometric outcomes across the three sweet-liking phenotypes adjusted for sex.

A comparison of BMI (A), FFM (B), BF% (C) and WC (D) across the three sweet-liking phenotypes adjusted for sex. Boxes represent the interquartile ranges, whiskers the minimum and maximum score of each anthropometric outcome, and solid lines the medians. The means for each phenotype are presented at the top of each relevant column. Significant differences estimated using Satterthwaite’s method are denoted with an asterisk (*p < 0.05, **p < 0.01, ***p < 0.001).