Twice a year, around a quarter of the world’s population dutifully reset their clocks. It may seem like a minor adjustment, but some people struggle with fatigue, irritability, and brain fog in the days following the transition. For others — especially night owls — the adjustment period can last for weeks. Circadian rhythms govern many physiological processes in plants, animals and even bacteria, highlighting life’s remarkable sensitivity to changes in environmental conditions. Your biological internal clock is controlled in a small region of the brain called the hypothalamus. It regulates hormone release, body temperature and metabolism. So if your circadian rhythm is out of kilter, those things will be disrupted too. Most people take three to seven days to adjust to daylight saving time (DST). However, night owls can take two to three weeks to realign their sleep-wake cycles. Research suggests diet also plays a role. People who eat high-fat diets seem to experience prolonged circadian misalignment after the spring clock change. A 2008 study on rodents found that those on high-fat diets adapted 20% …