Ask a Dietitian: Do Carbs Help You Sleep Better?
Getting enough sleep is vital when it comes to optimal brain function and immune health, as well as restoring energy and reducing the risk of chronic diseases. Studies have found that lack of quality sleep can be linked with obesity, diabetes, hypertension and cardiovascular risk.
Unfortunately, what you've been hoping was just an urban myth is true: the amount (and type) of carbohydrates you consume leads to poor quality sleep.
The good news? There are different types of carbohydrates, and while somer are responsible for poor sleep quality some can actually have positive effects. By making some adjustments to your diet, you can improve your sleep. Let's dig in.
What is good quality sleep?
Good quality sleep must contain right amount of slow wave sleep (SWS) and rapid eye movement (REM) sleep. SWS, aka deep sleep, has restorative function and can help muscle growth and repair. REM is more akin to a state of wakefulness, at least as far as sleep states are concerned. During REM sleep, our brain activity increases, our pulse gets quicker, and we have dreams.
Both phases of sleep play roles in learning and memory consolidation, and increase in duration as the night progresses (which is why it's ideal to hit that magic eight-hour mark every night).
Being able to fall asleep naturally is one of key factors at play in good quality sleep. When our systems are functioning at optimal levels, come evening time our brains convert the amino acid tryptophan into serotonin and then convert that serotonin into melatonin. Melatonin, also known as the sleep hormone, is what induces and maintains sleep.
How do carbohydrates affect sleep?
Carbohydrates play an important role in our quality of sleep. Carbs raise our insulin levels, which increases the availability of tryptophan in the brain, which in turn increases serotonin and melatonin – great news!
However, high-carb diets have been found to throw things off balance, increasing REM sleep, reducing non-REM sleep and causing delays in falling asleep in the first place.
Consuming large amounts of sugar-rich food and drink (also high in carbs) has been known to cause poor sleep. At the same time, very low-carb diets have been linked to insomnia, reduced REM sleep, and increased SWS (likely due to the reduction of serotonin and melatonin).
Good carbs vs. bad carbs:
To figure out which carbs are "good" and which are "bad" we can look at the difference between low GI carbohydrates and high GI carbohydrates.
What is GI? The glycaemic index (GI) of a food refers to how quickly it raises blood sugars after being consumed, as well as how much of the food is required to raise blood sugars.
Low GI carbohydrates, which are high in fibre, take longer to digest in comparison to high GI carbohydrates, which are digested quickly and provide a sudden increase in blood glucose and insulin. While foods such as milk and some fruits are high GI, they also contain important nutrients that are beneficial to our health.
Low GI carbohydrates include:
- Starchy vegetables (corn, potato)
- Legumes (lentils, chickpeas, kidney beans)
- Wholegrains (corn, oats, quinoa, wheat, brown rice)
- Certain fruits (banana, apples, oranges, pears)
High GI carbohydrates include:
- Refined sugars (white sugar, brown sugar, raw sugar)
- Sweets (cake, sweets, pastries, slices, soft drinks)
- Certain breakfast cereals (ones that are high in sugar)
- Honey and maple syrup
- Fruit juices
So, can eating carbs really help you sleep better? The answer is yes, but not just any old carbs. You need the right kind of carbs.
Ask yourself: am I consuming too many high GI carbohydrates and not enough low GI carbohydrates? If the answer is yes, up your intake of wholegrains and starchy vegetables and go easy on the soft drink, fruit juice and sweets. Your brain will be able to produce the right amount of serotonin and melatonin naturally and you'll start having the best sleep of your life.
Explore more content like this in our series, Ask a Dietitian.
Health & Performance Collective is the brainchild of Sydney Dietitians Jessica Spendlove and Chloe McLeod. They use their 20 years of combined knowledge and skills as dietitians to work with motivated people to live and perform at their best.