The Claim

In healthy young adults, short-term overfeeding reduces gut transit time compared to underfeeding and control diets, and this reduction is associated with altered fecal serotonin and Bacteroides levels.

Source: Effect of short-term dietary intervention on fecal serotonin, gut microbiome-derived tryptophanase, and energy absorption in a randomized crossover trial: an exploratory analysis

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
68score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

When healthy young adults eat more calories than needed for a short time, food moves through their digestive tract faster, and this is linked to changes in fecal serotonin and Bacteroides bacteria levels.

See the scientific wording

In healthy young adults, short-term overfeeding reduces gut transit time compared to underfeeding and control diets, and this change is associated with altered fecal serotonin and Bacteroides levels, suggesting a potential link between dietary energy load, gut motility, and microbial metabolism.

Why this might work

When a person eats more food than usual, the gut moves contents faster, which changes the types of bacteria present. Fewer Bacteroides bacteria mean less of an enzyme that breaks down a serotonin precursor, so less serotonin ends up in the stool. This drop in stool serotonin is linked to faster movement of food through the gut.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: Effect of short-term dietary intervention on fecal serotonin, gut microbiome-derived tryptophanase, and energy absorption in a randomized crossover trial: an exploratory analysis

    When healthy young adults ate more than usual for a week, their food moved through their gut faster, and their poop had less serotonin and different gut bacteria—exactly what the claim said.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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