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!"
The disruptions in Sandy's circadian rhythm is an extreme form of what we all just experienced with the turning forward of the clocks. Daylight saving time in the United States began at 2 a.m. on Sunday, March 12. And what seems like an innocuous one-hour shift forward in time can cause some unexpected grogginess as your body gets used to the new schedule. Temporarily, it will be darker in the morning but stay light out later. People who are particularly sensitive may find they feel more tired than normal or the opposite—wired and anxious. It's the equivalent of mild mass-induced jet lag.
What happens to your gut bacteria when you're jet lagged?
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.
And more importantly, how do disruptions in your circadian rhythm (sleep-wake cycle) affect your health? Studies in both mice and humans have shown an increased risk of obesity and metabolic syndrome due to circadian rhythm disruptions. Thinking back to Sandy, she was constantly disrupting her body's natural circadian clock, resulting in weight-loss resistance.
But can jetlag really make me gain weight?
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.
Circadian rhythm disturbances—like the ones seen in these mice as well as jetlagged business travelers and nightshift-workers—can induce internal changes to a more unfavorable gut microbiome that can lead to pre-diabetes and obesity. And it's a snowball effect: One influences the other, which in turn exerts its influence back.
What can I do to protect my 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.
If you’ve struggled with weight loss resistance, consider the fact that the root of your problem may be a gut microbiome in disarray. Sleeping and eating on a regular day-night schedule is crucial in your quest for optimal weight. If you're looking for where to begin, I’d love to help you achieve your weight loss goals by optimizing your gut health with my free Quick Start Guide to a Happy Gut.