Diabetes is one of the leading causes of death and disability worldwide. In our country, Diabetes has reached epidemic levels. There are 20 million diabetics in the USA!
The crazy thing is that diabetes develops from such seemingly innocuous lifestyle habits. All it takes is eating a little too much fat and sugar, not exercising enough, getting stressed, and not sleeping enough for your system to go out of whack. Next thing you know, if you have a genetic predisposition to diabetes, that is, if anyone in your family has it or if you had gestational diabetes, you’ll find yourself developing poor blood sugar control and eventually, diabetes.
And it doesn’t even take that long to happen! A study was published in The Lancet, in 1999, after only 6 nights of sleep deprivation in healthy, young men, blood sugar was already measurably higher? These young men slept from 1 am to 5 am for 6 nights and their blood sugar started climbing up. Now, I’m not saying that you can develop diabetes in 6 days (in fact, when these men started sleeping normal amounts, their blood sugar normalized!) But, I am telling you that it doesn’t take much self-abuse to start impacting your body.
Now, imagine what happens to shift workers, or new parents, who are, perhaps a little older and less healthy than those test subjects? Night after night of poor sleep for months, even years, and your body just doesn’t work like it used to. It becomes harder to lose weight, and carb cravings get stronger. This is not the case for everyone, of course. There are many more factors at play. Some people have better adrenal reserves, or more resilient hormonal profiles. Some parents lose weight from stress, while others gain it. But for those who have the tendency to gain: here’s part of the explanation.
While we may all be aware that eating too many carbs, sugary foods and drinks will move us towards diabetes, most people have little awareness about the impact that sleep deprivation has on our blood sugar. How does a lack of sleep affect blood sugar and lead to diabetes? In short, it throws off your hormones.
For one, a lack of sleep impacts your hunger levels. There are two main hormones involved in regulating your hunger, Ghrelin, and Leptin:
This is the hunger hormone. It’s a fast-acting hormone that goes up when you’re hungry and goes down after you eat a meal. It’s mainly produced by cells of the stomach and when you don’t sleep enough, your body makes more of it. You’ll feel more hungry if you don’t sleep.
On the other hand, leptin is the stop eating hormone. It’s an appetite suppressant and tells the body to stop eating. It’s made by your adipose, or fat cells. Sleep deprivation lowers leptin, so when you sleep less, your body makes less of the “stop eating” message.
So, if you don’t sleep, you have more ghrelin, and feel more hungry than usual. And, if you don’t sleep, you have less leptin. Your body says – eat more, and don’t stop! And you know that after a poor night’s sleep, you’re not going to be reaching for the celery sticks! Really. You’re not. It’s been shown that sleep loss makes you crave carbs and sugar. If you don’t sleep enough, you’ll be reaching for the chips, and the bread, and the pasta and cookies.
The above scenario describes how leptin and ghrelin work in a person who is generally not overweight. If you add obesity to the mix, you have a more complex situation. (By obesity I mean those who have a Body Mass Index of 30 or higher.)
After you hit a certain cut-off weight, the above rules no longer apply. In obesity, all the hormonal rules change. Obese people, perhaps surprisingly, have decreased levels of the hunger hormone, ghrelin, so they are not actually hungry. The hunger sensation is technically turned off. At the same time, obese people actually have high levels of leptin, the stop eating hormone. The problem in obesity is that there is a malfunction, in which, the obese body can’t hear leptin’s message –that’s called leptin resistance. In obesity, the body can’t hear stop eating, even if they actually have a lot of leptin.
So, in the case of obesity, the person does not actually feel hungry but is not hearing any message that says stop eating. It’s a situation of feeling like this: I’m not really stomach-growlingly hungry but I’m eating this cupcake anyway. On the other hand, in people who have a normal weight, inadequate sleep makes them hungry (ghrelin) and less likely to stop eating (low leptin). Inadequate sleep starts you on the road to overeating.
Another hormonal pair that is affected by inadequate sleep is cortisol and insulin.
Cortisol is the keep-a-sugar-supply-handy hormone. It’s one of your fight or flight stress hormones. Biochemically, it belongs to a class of chemicals known as glucocorticoids. While cortisol has many, many effects on the body, it’s chemical class helps you remember that one of cortisol’s primary actions is to raise glucose (blood sugar). Cortisol is secreted by the adrenal cortex, or outer layer of your adrenal glands, which sit like little hats on top of your kidneys. It makes your body blood sugar-ready to fight a lion. When you lack sleep, cortisol goes up. You can think of cortisol as the enemy of the next hormone, insulin.
Insulin is the let-glucose-in hormone. It goes around to your body’s cells and tells them to open up and, let glucose in. Your pancreas makes insulin. You know those movies where a spy is trying to get into a top-secret research lab? He puts his thumb on a sensor, which then unlocks and opens a door? Well, in this situation, insulin is the spy’s thumb. When insulin docks in an insulin receptor on a cell, that cell suddenly opens up by inserting a special portal-like protein (GLUTs) on the surface of its membrane. Insulin tells the cells to let glucose in, and the cells should obey, and open up to glucose. However, if you don’t sleep, your cells won’t listen to insulin.
So, from the above information, you can gather that cortisol and insulin generally have opposite agendas.
Cortisol wants glucose to stay in the blood and to be available to muscles and brain for fighting, while insulin wants glucose to leave the blood, and go into the less important cells, where it can get used up as everyday cell fuel. Of course, like any other hormone story, there’s more to this narrative, but we’ll keep it simple, for now.
When you don’t sleep enough, you body considers that a stressor. When your body is under stress, you release cortisol from your adrenal glands.
Cortisol is powerful and makes your body stop listening to insulin. Why would it do that? Well, if you’re under stress, your body thinks it has to prepare you to fight or run. Cortisol tells the body, “Shhh! Stop whatever you’re doing and prepare for a fight.” It overpowers all other messages to make sure you have a quick supply of sugar to fuel those leg muscles to run, or those arms to punch.
In the meantime, your pancreas tries to make up for the fact that no one is listening to the insulin message by secreting more insulin (hyperinsulinemia) and trying to have a louder message, but it only ends up shooting itself in the foot with this strategy. Eventually, your cells get tired of listening to insulin’s constant nagging… “Open up and let glucose in, open up and let glucose in, blah, blah, blah, blah, blah…” and they stop responding to insulin (insulin resistance). Now, your cells have just stopped listening to insulin and your sugar can’t get into your cells. It just stays in the blood. You have constantly elevated blood sugar.
However, the stress of not sleeping is not the same as the stress of fighting a lion. Most things that deprive you of sleep don’t involve running or fighting. You’re probably not sleeping because you’re cramming for a test, or your baby woke you, or, the most likely scenario – you’re getting some me time on the couch watching the latest episode of Girls or Game of Thrones, or True Detectives. In which case, that elevated blood sugar, due to lack of sleep and cortisol, is serving no good purpose. It’s not fueling muscles! Instead, it’s wreaking toxic havoc on your nerves, your blood vessels, your brain, and your kidneys, to name a few.
To make things worse, cortisol can raise your blood sugar whether you have eaten or not. In other words, you don’t need to have eaten sugar to have high blood glucose. Your body can make it’s own sugar! This process is called gluconeogenesis, or, making new glucose, and it primarily takes place in your liver.
To recap, if you don’t sleep, your stomach secretes more of the hunger hormone, ghrelin, so you feel hungrier. You also secrete less leptin, the stop eating hormone, so you won’t stop eating. Next thing you know, you’re eating a lot of carbs.
At the same time, if you don’t sleep, your body simply gets stressed out. When you are stressed, you secrete cortisol, the stress hormone. Cortisol wants to keep sugar in your blood, thinking, that you might need it to run away from something. So, it makes you ignore insulin, the open-up-and-let-glucose-into-the-cells hormone. Eventually, your cells stop being able to hear insulin and can’t let glucose into the cells.
Within a few short days of this inadequate sleep behaviour, you’ve started the ball rolling towards diabetic patterns. You’re overeating carbs, you’re stressed, and you’re keeping your blood sugar higher than normal.
So, here’s what you need to do: Go to sleep! You can watch Game of Thrones later. Really! Put down the remote control. Turn off your computer, and get 7-8 hours of quality shut-eye. You’ll eat less cupcakes, you won’t tip the scales and throw your hormones into a state of confusion. You won’t feel so stressed out. You’ll do less emotional eating. Your body won’t be so inflamed. You’ll save your kidneys, you won’t have a stroke, you won’t need an amputation or any of the other things that come along with diabetes. You may even lose that belly fat with this one simple tip…!