Your gut bacteria keep time by your meals — and tell your body when to eat up

We think of body clocks as set by sunlight. But some of your most important timekeepers never see the sun: they live in your gut. Carnegie Mellon University researchers led by Zheng Kuang found that gut bacteria sense when you eat — food itself is their clock signal — and in response release molecules that tell intestinal cells when to absorb nutrients. In other words, your microbes run a mealtime schedule and pass the timetable to your body, coordinating digestion with your daily rhythm. 'These bacteria don't have access to light,' Kuang said. 'Instead, they use food as a signal to tell time. When we eat, they produce molecules that communicate with our intestinal cells and help coordinate nutrient absorption.' The discovery fills a long-standing gap in how the microbiome shapes metabolism — and why when you eat may matter nearly as much as what.