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.

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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.

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.”

Still, more research needs to be done.

Better sleep doesn’t come overnight, though.

During her first month on the keto diet, Keiwana Eaton dropped 25 pounds… yet found herself awake and full of energy at midnight.

“I’m normally asleep by 9 pm — 10 if there’s a good movie on — but never later than that,” says the Opelika, Alabama resident.

Yet on keto, “I was reading, cooking, cleaning, feeling like I had a full day’s rest… with no rest at all,” Eaton says.

“Keto insomnia” is a real, albeit often short-lived, phenomenon for some people. And like keto’s ability to help sleep, its causes are still being sussed out.

Low levels of serotonin and melatonin, neurotransmitters that help with sleep, as well as higher than normal energy levels, may be partly to blame. “[You’re] not eating many carbs so you don’t have the L-tryptophan [an amino acid found in foods] which supposedly helps with increasing serotonin and melatonin,” explains Rissetto.

Diane SanFilippo, a certified nutrition consultant and author of “Keto Quick Start: A Beginner’s Guide to a Whole-Foods Ketogenic Diet,”notes that once blood sugar spikes and crashes from a carb-rich diet finally dissipate, regulation of cortisol, the “stress hormone,” kicks in and also helps usher in improved sleep.

And, “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,” SanFilippo adds.

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Is the keto diet right for you? Getty Images

Just because you’re looking for better shut-eye doesn’t mean you should hop on the keto bandwagon. (No matter how much you love the idea of cheese at every meal.)

“I don’t recommend keto for those who struggle to keep weight on, for those with diagnosed eating disorders, children of rapid growth and development ages, and the elderly for whom weight maintenance can be tricky,” says SanFilippo.

Check with your doctor first to see if this eating plan’s a good fit for you. In the meantime, to get a better night’s rest, you can:

  • Cut sweets from your diet. “No more pastries, sweetened drinks, or sugary treats,” says SanFilippo. Try fresh fruit instead. The more sugar you eat during the day, the more often you’ll wake during the night.
  • Go easy at Starbucks. “Even 1 cup of coffee early in the morning can negatively affect sleep at night,” SanFilippo notes. Switch to half-caf for a week, then eventually to decaf, then no coffee at all, and “you’ll likely find a marked improvement in sleep quality,” she says.
  • Ditch the booze. “Alcohol is a touchy subject for many who lean on it to relax. However, removing your daily drink can help you sleep more soundly and improve your energy the next day, too,” says SanFilippo.
  • Up your exercise. “Adding 30 to 60 minutes of anything from walking to weight lifting to yoga to high-intensity training will all help to improve your sleep quality,” SanFilippo says.