By now, you may have heard that less sleep is bad for your health. That it is linked to heart problems, weight gain, and insulin resistance. We know that our circadian rhythm is delicate and disrupting it can increase food intake and weight gain. But what exactly triggers those changes?  Is it simply less sleep overall, or is it about going to bed late, or waking up too early? 

A new study in the journal Nutrients demonstrated that on a night of less sleep (4 hours), when you do get sleep may matter. Using a randomized crossover study design, they compared hunger and appetite hormones ghrelin and leptin and measured the desire for food in young healthy men under three different sleep conditions. The intriguing findings may change the way you approach your mornings.

When the study subjects slept in the later half of the night, their hunger hormone ghrelin levels were similar to those after a good night’s sleep. However, when they slept early in the first half of the night, their ghrelin levels increased and their desire for food was higher first thing in the morning compared to a night of normal sleep.

For those who frequently wake up early for flights or early work shifts, this study suggests that your hunger pangs around 7 or 8 am are hormonally driven and predictable. The good news is that you can plan for it by being mindful of your breakfast choices and moderating your intake throughout the rest of day, especially if you have a big meal in the morning.

It’s important to note that this study was conducted in healthy young men, so the findings may not be the same for older females with obesity, for example. Additionally, the study did not measure actual food intake, which is ultimately what causes weight gain. And the sample size was small.  Therefore, it would be beneficial to repeat the study with a larger and more diverse sample size to verify the results.

In conclusion, if you find yourself needing to miss sleep, this study suggests that staying up late might be better for your appetite than waking up early, if you have the choice. However, if waking up early is unavoidable, proper planning for a healthy breakfast when hunger strikes is crucial. And of course, remember that everyone is an individual and ultimately you should listen to your body and learn what works best for you through trial and error.