Can Jet Lag Increase Your Risk of Diabetes?

The connection between disrupted circadian rhythms and metabolic health has attracted growing scientific interest, but it is not always clear how much effect a few days of jet lag has compared with long-term lifestyle habits. While temporary fluctuations in blood sugar may occur under certain circumstances, it is important to understand whether these changes are short-lived, who is most vulnerable, and what practical steps travellers can take to minimise any impact. An expert can help separate established evidence from common assumptions and explain what this means for everyday travellers.

Jet lag and blood sugar regulation

Kanikka Malhotra, Consultant Dietician & Diabetes Educator, tells indianexpress.com, “Yes, and the mechanism is more direct than most people realise. The body runs on an internal master clock, tucked deep in the brain, that regulates insulin sensitivity alongside sleep and hunger hormones. When this clock is thrown off by crossing time zones, insulin sensitivity can temporarily dip, meaning the same meal produces a higher blood sugar spike than usual for a few days. This is a short-term, reversible response, not diabetes itself.”

However, she notes, research on shift workers and frequent flyers suggests that repeated, chronic circadian disruption over years can gradually impair glucose metabolism and contribute to insulin resistance, one of the pathways to type 2 diabetes. “The key difference is duration and frequency. An occasional trip causes a temporary blip that resolves once routine returns, while ongoing disruption, night after night, is what tips the scales toward lasting metabolic damage. Think of it as the difference between a pothole and a worn-out road,” says Malhotra.

Who is most affected by travel-related blood sugar changes?

People with prediabetes or existing diabetes tend to notice the sharpest fluctuations, since their insulin response is already less flexible and has little buffer to absorb additional stress. Those with obesity and shift workers, who face chronic circadian misalignment, are also more vulnerable. Interestingly, even healthy individuals are not exempt, though their bodies typically recover faster.

Malhotra explains, “Four factors compound the effect. Disrupted sleep reduces insulin sensitivity almost immediately, irregular meal timing confuses the digestive hormones that anticipate food at certain hours, stress raises cortisol, which independently pushes blood sugar upward, and reduced physical activity during travel days means less glucose is being used by muscles. Together, these create a temporary metabolic pile-up. Someone flying from Delhi to New York, for instance, may find their post-dinner readings higher than usual for the first two or three days, purely from this combination.”

Minimising the metabolic effects of jet lag

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.