Eating when you should be sleeping—the proverbial midnight snack, say, or the meals of night-shift workers—could put you at higher risk of obesity, Time reports. A new study fed two groups of mice the same high-fat diet on opposite schedules; the group that ate during “normal” waking hours had a weight gain of 20% after 6 weeks, while the other group gained 48%. The mouse study, the first of its kind, mirrors observational research on humans.
“If an experiment like this is replicated in humans, it might clarify for us just how much time of day matters when it comes to obesity,” an expert says. One of the study’s authors says “our bodies are naturally cued to eat at certain times of the day.” As a result, “dining at the wrong time might affect the body's ability to maintain its energy balance.” This has to do with a complex blend of hormones that can spiral out of control if the natural circadian rhythms are upset.