"The keto diet is a low-carbohydrate diet that helps with glucose control, insulin sensitivity, and even the decrease of triglycerides in the blood," explains Vanessa M. Rissetto, a registered dietitian/nutritionist who specializes in weight loss and weight management.
People who follow this diet limit themselves to no more than 20 g of carbs per day. But unlike other diets that require strict avoidance of fatty foods, the keto diet encourages the consumption of eggs, meat, butter, cream, mayonnaise, and most kinds of cheeses.
Carbs are the body's source of energy. Once the body uses them up, they enter a metabolic stage known as ketosis. This is when the body starts to burn stored fat as fuel. That is why keto diet followers aren't discouraged to eat as much fat as they want – they're going to burn them anyway.
The keto diet is not only for weight loss, though. It has been around since the 1920s, and it was first recommended by doctors to patients who were suffering from epileptic seizures. Apparently, it is very effective as it is still used to reduce seizures today. (Related: The keto diet: Tips to make sure that the eating plan is working for you.)
When people go on a keto diet, they introduce big changes to their body. Dietary changes usually affect sleep.
Michael J. Breus, a clinical psychologist with a specialty in sleep disorders, says, “It’s not uncommon to hear people report sleep problems when they start a ketogenic diet. A big reduction in carbohydrate intake combined with significant increase to fat intake – which happens on a keto diet – can cause changes to sleep patterns. These macronutrients have different effects in the body and can affect sleep in distinct ways.”
However, once the body acclimatizes to the changes imposed by the keto diet, everything changes for the better.
Breus notes that there are not many studies exploring the effects of the keto diet on sleep, but there are a few reporting that it does improve sleep quality and timing, and overall quality of life.
A good example of this is a recent study published in the journal Nutrients, which reported that a very low-calorie keto diet significantly reduced daytime sleepiness in a group of obese patients.
A Swedish study published in Epilepsia found that children with hard-to-treat epilepsy slept better, experienced more REM sleep, and felt significantly less sleepy during the day after following a keto diet. Altogether, these changes improved their quality of life.
One possible explanation for this is that the ketogenic diet may have an effect on a brain chemical called adenosine. Adenosine is important in regulating sleep.
As adenosine builds up in the body throughout the day, it slowly decreases alertness and wakefulness, so during nighttime, the body succumbs to a deeper, slow-wave sleep.
"Studies show that a ketogenic diet promotes adenosine activity in the body, helping to relax the nervous system, as well as reducing inflammation – all of which can help improve sleep,” says Breus.
Another possible reason could be the regulation of cortisol, a stress hormone. Cortisol activity goes down once blood sugar spikes and crashes finally dissipate. This improves sleep quality.
"When people don’t have afternoon energy slumps anymore – another benefit of keto – reaching for a 3 pm coffee tends to stop, which can also help sleep quality improve,” says Diane SanFilippo, a certified nutrition consultant.
Despite these benefits of the keto diet, experts emphasize that it is a diet, not a sleep aid. People shouldn't use it willy-nilly to remedy their sleeping problems. Consulting with a healthcare provider is still the best option for people who are suffering from sleep disorders. And despite the scientific evidence, further studies are still needed to understand the mechanisms behind the keto diet's influence on sleep.