What your gut does at 2am on a call night.
It is 2:14am and the pager fires. Upper GI bleed. I roll out of the narrow call-room bed, walk past a communal kitchen where someone has left half a pizza in its box, and eat two cold slices standing up before I head to the endoscopy suite. I spend my days counseling patients on dietary timing and the microbiome — and a good share of my nights systematically dismantling that advice in my own body.
The gut keeps its own clock. Gastric acid output peaks in the evening; colonic motility runs nearly silent between midnight and 6am — which is why most people move their bowels in the morning, not at 3am. Eating cold pizza now, I am asking the factory to run during its maintenance hours.PMID 16968601 · circadian GI rhythms
It is not just timing. A landmark 2014 study showed the microbiome oscillates across the day, driven by feeding rhythm — and that inducing jet lag distorts those oscillations enough to transfer metabolic dysfunction into germ-free mice given the stool.Thaiss 2014 · Cell · PMID 25417104
Your gut has a clock. Respect it when you can. Repair it when you cannot.