This Unexpected Thing Messes With Your Gut Health (And Has Nothing To Do With What You Eat)

Sandy is a patient that travels across multiple times zones (from New York to Europe) at least twice a month. When she came to see me, she was frustrated that she couldn't lose any weight. Despite her best efforts to exercise regularly and restrict simple starches and sugars, she frustratingly exclaimed, "The scale simply does not budge no matter what I do!"

Turns out bacteria have their own circadian rhythm, which operates approximately on a 24-hour cycle. These rhythms and other cyclical patterns are studied by a branch of biology known as chronobiology. There's one problem, though—there's no light down in your gut. So how do these bacteria sense a cycle they cannot see? Well, partly it comes down to your eating patterns, which control fluctuations in your microbiome over the 24-hour period.

Let's jump across the world to Israel, where the Weizman Institute of Science has studied the effects of circadian rhythm disturbances on mice and their microbiomes by creating artificial jetlag. The researchers induced “jetlag” in mice by shifting the lights-on time forward by eight hours, keeping them on the new cycle for three days, then going back to the old cycle. This was the equivalent of putting the mice on a flight from New York to Dubai every three days for an entire month. When these mice were fed a high-fat diet, they gained more weight than non-jetlagged mice on a normal schedule. And these changes were transferable to germ-free (microbiome-free) mice through fecal transplant, leading also to weight gain—proving that the issue is transferable through the gut microbiome.

Ultimately, Sandy had to face the hard fact that her work travel schedule was at the root of her weight loss resistance. We discussed the ramifications of these circadian reversals on her metabolism. She negotiated a significantly reduced travel schedule, mainly working from the New York office. As a result, while making no additional changes to her diet and exercise—which were already disciplined—she was finally able to lose those stubborn last 10 pounds.