Your sleep cycle is built on the circadian rhythm, which responds to light and dark (via the National Institute of General Medical Sciences). When you disrupt the rhythm, it has immediate effects on your appetite. Research in the Journal of Sleep Research (JSR) showed any disturbance in your sleep can increase your ghrelin levels and decrease leptin levels. Ghrelin is the hormone produced and released by the stomach, which tells your brain when your stomach is full and empty, according to the Cleveland Clinic. The hormone leptin is produced by the fat cells and tells your brain when your body has enough fat stored (via Healthline). So, the disruption of the ghrelin and leptin from DST makes your hunger signals out of wack, and you feel like you’re starving.
Additionally, a study in the British Journal of Nutrition illustrated when you’re tired, you make less healthy choices. Given your increased hunger and less interest in healthy choices, you crave high-fat, unhealthy foods like donuts, candy, cake, pizza, and fast food.
The adjustment to DST can take days to weeks, per the Mayo Clinic. Making adjustments before DST can help you to keep your sleep and appetite normal. For example, adjust the time you go to bed by 15 minutes a few weeks before DST, and take naps as needed during the week after DST. Mayo Clinic also recommends sticking with your regular schedule as best as you can.