Dietary fiber induces a fat preference associated with the gut microbiota

Abstract

Eating behavior is essential to human health. However, whether future eating behavior is subjected to the conditioning of preceding dietary composition is unknown. This study aimed to investigate the effect of dietary fiber consumption on subsequent nutrient-specific food preferences between palatable high-fat and high-sugar diets and explore its correlation with the gut microbiota. C57BL/6NJcl male mice were subjected to a 2-week dietary intervention and fed either a control (n = 6) or inulin (n = 6) diet. Afterward, all mice were subjected to a 3-day eating behavioral test to self-select from the simultaneously presented high-fat and high-sugar diets. The test diet feed intakes were recorded, and the mice's fecal samples were analyzed to evaluate the gut microbiota composition. The inulin-conditioned mice exhibited a preference for the high-fat diet over the high-sugar diet, associated with distinct gut microbiota composition profiles between the inulin-conditioned and control mice. The gut microbiota Oscillospiraceae sp., Bacteroides acidifaciens, and Clostridiales sp. positively correlated with a preference for fat. Further studies with fecal microbiota transplantation and eating behavior-related neurotransmitter analyses are warranted to establish the causal role of gut microbiota on host food preferences. Food preferences induced by dietary intervention are a novel observation, and the gut microbiome may be associated with this preference.

Fig 1. Experimental design overview.

Twelve mice underwent a 1-week habituation period followed by a 2-week dietary intervention and were fed one of the following diets: (1) control; (2) high-fiber inulin. After the dietary intervention, the mice were subjected to a 3-day eating behavioral test to choose between palatable high-fat and high-sugar diets. Fecal samples were collected at Day 0 (pre-intervention), 4, 8, 12, 14 (post-intervention), and 17 (post-eating behavioral test). Created with BioRender.com.

Fig 2. Nutrient-specific food selection results.

Fig 2A shows a significant difference in the high-fat and high-sugar feed intakes in inulin-conditioned mice (P = 0.0043); however, no significant difference was detected in the control group (P = 0.39). Fig 2B shows no significant differences in the total test diet intake between the two groups (P = 0.87). Fig 2C shows the fat preference scores of the inulin-conditioned and control mice over the course of the three-day eating behavior test. The inulin-conditioned mice showed a significant increase in fat preference on Day 3 (P = 0.031).

Fig 3. Taxonomical features of gut microbiota post-dietary intervention.

Fig 3A: OTU-level taxonomic composition of the control and inulin-conditioned mice pre-intervention and post-intervention; Fig 3B: Volcano plot of the MaAsLin2 model output, showing the top 10 taxa that were significantly enriched or depleted in the inulin-conditioned mice compared to the control group; Fig 3C: Longitudinal dynamics of the top 10 taxa showing significant differences in abundance between the two groups.

Fig 4. Correlation between fat preference and gut microbiota.

24 OTUs significantly correlated with fat preference. Four out of 24 OTUs positively correlated with fat preference: OTU00065 Oscillospiraceae, OTU00002 Bacteroides acidifaciens, OTU00073 Clostridiales, and OTU00280 Clostridia (q = 0.0413, 0.0562, 0.0849, and 0.0849, respectively.) The size and color intensity of the dots represent the strength of the correlation.