Insulin is the kind of word that everyone has heard and few people understand, but it’s critically important for everybody on Earth. Insulin affects how well your body absorbs nutrients, how it processes carbohydrates, and plays a major role in your body fat—both how much you have and how easily you can lose it. Since your body fat has a real effect on your inflammation and risk of chronic disease, how you manage your insulin is significant not only with regard to your diabetes risk, but the quality and length of your life.
And yes, sleep has an enormous impact on your insulin.
First, let’s get clear on the basics of insulin. Whenever we eat carbs (and a little bit when we eat protein), the pancreas releases insulin, which is a hormone that helps us move the sugars out of our bloodstream and into our muscles and organs where they can later be used for energy. Essentially, carbs give you energy, and insulin is what helps move the energy from your food into your own energy stores.
But what really matters when it comes down to diabetes and overall health is a factor called insulin sensitivity, which measures how well your body responds to the hormone.
See, your insulin spikes when you consume carbs, and it really spikes when you eat a source of carbohydrates without much fat, fiber, or protein to slow the digestion—candy, Oreos, and orange juice are great examples of foods that send your insulin soaring. If you eat sugary junk very frequently, you’ll spike your insulin so often that your body becomes less sensitive to it, sort of in the same way that drinking coffee every morning makes you more resistant to its effects.
If you have poor insulin sensitivity (also known as insulin resistance), you do a less efficient job of digesting carbohydrates, and carbs are a lot more likely to make you gain fat. And as you become more and more insulin resistant, the pancreas needs to produce more and more insulin to do its job, until it eventually gets worn out and stops being able to produce the hormone properly. That’s when type 2 diabetes is diagnosed.
So whether you have a family history of diabetes, or you just want to see your six-pack, your insulin resistance is something you want to keep an eye on. You might have picked up on the fact that maintaining a diet that’s low in sugar and high in fiber, protein, and healthy fats is a good start. But there are a lot of ways to improve your insulin sensitivity that have nothing to do with diet: Regular exercise, for example, is a well-known remedy. And one of the simplest and most effective ways to boost your sensitivity, slash your diabetes risk, and improve your body fat, is to simply close your eyes and go to sleep.
A 2012 study received widespread media attention when it found that sleep deprivation actually impairs the ability of fat cells to respond to insulin. Seven young men and women were studied for eight days, and were only permitted 4.5 hours of sleep per night during the second half of the experiment. At its conclusion, the participants’ insulin sensitivity was, on average, 16 percent lower than it had been at its beginning, and the sensitivity of their fat cells had decreased by thirty percent, leaving them at the same levels usually seen in people who are obese or have diabetes. The fat cells needed three times the regular amount of insulin in order to activate an enzyme called Akt, which is essential for regulating blood sugar—this was the first study to find the specific cellular mechanism that connects a lack of sleep with a higher diabetes risk.
The senior author of the study told CNN, “This is the equivalent of metabolically aging someone 10 to 20 years just from four nights of partial sleep restriction… fat cells need sleep, and when they don’t get enough sleep, they become metabolically groggy.”
To make matters worse, a lot of the diabetes markers exacerbate each other as well: eating a lot of sugar can increase urination, which can interfere with sleep, which can also make you more prone to mindless snacking and higher levels of body fat, all of which is a perfect storm for insulin resistance and a ticket to type 2 diabetes.
Fortunately, reversing the trend is also synergistic: eat plenty of protein, fiber, and good fats, exercise regularly, sleep deeply, and you’ll create the best possible environment for insulin sensitivity, longevity, and a healthy, powerful body.