3 Reasons Why Poor Sleep Can Cause Weight Gain



Dr. Anna and myself are very disciplined when it comes to establishing our sleeping patterns. It is not abnormal for us to be asleep by 8:30 PM and awake around 6 AM (or when Little Dog and Polly decide it’s time to get up). Sleep, nutrition, chiropractic, and physical activity levels are hallmarks of a healthy lifestyle (and the low hanging fruit for many chronic maladies).


However, as I am writing this, my normal life routine has been flipped upside down and a normal sleep cycle seems like a dream right now rather than a normalcy. I was inspired to write this post based on my experience from the past week of being on the current mission I am on (if you are interested in other experiences from this mission, stop in the office and pick up a newsletter I recently wrote. We decided not to publish that one online).

When we first got to our staging base we were put into crew rest and told we would be alerted to fly in 12 hours. Those times got pushed to the right another 8 hours. Then our plane that we were sharing with another crew had maintenance issues, pushing our schedule to the right again another 8 hours. By the time we had flown (2:45 AM take off) we had been in and out of crew rest for 3 days. I had gotten a decent amount of sleep but it was never a solid 8 hours at a time, instead it was 3 hours here, 4 hours there, and never a normal 8-9 PM- 5-6 AM.

This can wreak havoc on you mentally and physically. Every week I have patients tell me that they have gotten used to sporadic sleep cycles and swing shift working schedules. The truth is your body never really adapts to poor sleep. The most common consequence of poor sleep schedules is weight gain and the inability to lose weight. In fact, one recent study demonstrated that participants who slept an average of 5 hours a night for only one week gained an average of 2 pounds. IN A SINGLE WEEK!

Why does your body have the tendency to gain weight due to poor sleep? Here are three hypothesized reasons as to why.

  1. Hormones. Specifically Melatonin, Leptin, and Ghrelin. Interrupted sleep cycles cause lower levels of melatonin. Melatonin is a hormone produced in the brain in response to lower light. Melatonin is your “winding down” hormone that nudges your body to begin to go to sleep. Long term sleep interruption lowers this hormone resulting in chronically worsened sleep and is associated with increased eating. Leptin is a hormone produced by fat cells in your body that communicates with the hypothalamus in the brain to regulate and control appetite. Just like melatonin, leptin can be reduced during periods of low sleep causing an increase in appetite and a propensity to eat more. Unlike Leptin and Melatonin, Ghrelin has been shown to be elevated during periods of erratic and low sleep cycles. The opposite of Leptin, Ghrelin is considered to be a hunger hormone and increases levels of hunger. The combination of decreased Leptin and increased Ghrelin increases the likelihood of eating more than you normally would.

  2. Decreased energy levels equates to decreased physical activity levels. This one is pretty straight forward. If your amounts of sleep and your sleep quality are suffering you will have less energy during the day resulting in less physical activity (and possibly lower calories burned due to the constrained energy model). Couple less physical activity with increased appetite and you have a recipe for disaster.

  3. Less thermoregulation. Ever notice that after a night of really bad sleep or very little sleep you find yourself somewhat colder than normal? This is because your body has less ability to regulate your body temperature. Temperature regulation burns calories to a certain degree. Less thermoregulation equates to less calories burned.

Of course this is a simplified overview of three possible reasons why poor sleep can cause weight gain, but they are worth considering. In my experience, people are quick to dismiss poor sleep as a causative factor of overall health problems, but poor sleep should not be overlooked. Like I said before, sleep quality is often times low hanging fruit.


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