After a short period of adjustment, those who follow the ketogenic diet find they’re more alert during the day and sleep deeper at night.
Can the keto diet help you catch higher quality Zs? Getty Images
Seven months ago, when April Stratemeyer first started the ketogenic diet — which eschews carbs in favor of high-fat foods — her sleep cycle veered way off course.
“I would try to go to sleep at my normal time, and was wide awake. When I would finally fall asleep, I’d toss and turn, waking up every couple hours,” says the Seattle resident.
Her FitBit confirmed the drop in sleep quality. It informed Stratemeyer that she was getting only 5 to 10 percent deep sleep when she usually clocked around 20 percent.
Yet after a few weeks went by, Stratemeyer noticed another, more positive change. She was going to bed at a reasonable time, falling asleep fairly quickly, and sleeping deeply throughout the night. And in the mornings, she woke up refreshed and ready to go, rather than groggily hitting her snooze button a handful of times.
“I learned relatively quickly that sometimes, your body can do weird things on keto,” Stratemeyer says.
One of those “weird” things may be improving sleep.
The food-sleep connection
Keto — all the rage these days — is a low-carbohydrate diet that “helps with glucose control, insulin sensitivity, and even the decrease of triglycerides [fats in your blood],” explains Vanessa M. Rissetto, MS, RD, CDN, a registered dietitian/nutritionist who specializes in weight loss and weight management.
Despite the buzz, it’s no overnight fad. The ketogenic diet has actually been around since the 1920s, when doctors “prescribed” it to help reduce epileptic seizures. (And it’s still used for that purpose today.)
People following a keto diet aim to eat no more than 20 grams of carbohydrates per day. (As a point of reference, one plain bagel = 48 grams of carbs.) Fatty foods like eggs, meat, butter, cream, mayonnaise, and most cheeses aren’t just acceptable — they’re encouraged.
Carbs are your body’s favorite source of energy. Once your body uses them up, it enters a metabolic stage called ketosis and starts to burn fat stores as fuel instead.
“Some people do [keto] because they’ve heard that it helps with the management of blood sugar. Other people use it as an excuse to eat cheeseburgers and not feel guilty,” Rissetto notes.
So what does this have to do with sleep?
“It’s not uncommon to hear people report sleep problems when they start a ketogenic diet,” notes Michael J. Breus, PhD, a clinical psychologist with a specialty in sleep disorders. “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.”
Only a small number of studies have closely examined how keto diets affect sleep, says Breus. But what they show so far is that “this very low-carb, high-fat diet may offer benefits for sleep, both through weight loss and other pathways.”
For instance, in a recent study published in the journal, Nutrients, a group of Spanish and Columbian scientists found that a very low-calorie keto diet significantly reduced daytime sleepiness in a group of obese patients.
Previous research from the Medical University of South Carolina followed 6 morbidly obese teens who spent 4 months on a keto diet. While all showed sparse REM (dreaming) sleep and excessive slow-wave (deep) sleep at the beginning of the experiment, the reverse was true at the end.
A separate Swedish study found that children with hard-to-treat epilepsy who followed a keto diet slept better, experienced more REM sleep, and felt significantly less sleepy during the day — all of which improved their overall quality of life.
One theory as to what’s going on: Ketogenic diets could have an effect on a brain chemical called adenosine that’s important to sleep regulation, Breus says.
“Adenosine builds up in the body throughout the day and contributes to our feeling increasingly less alert and wakeful as the day goes on, eventually helping to promote deeper slow-wave sleep at night,” explains Breus. “Studies show a ketogenic diet promotes adenosine activity in the body, helping to relax the nervous system, as well as reducing pain and inflammation — all of which can help improve sleep.”