Learning to get by on less sleep is not an uncommon goal. Some people claim that sleep gets in the way of life — more time awake means more productivity, and more time to work on goals and hobbies.

Although I often stand by the mantra of “Listen to Your Body”, I understand the frustration people feel when they oversleep, or when they spend 10 hours a day in bed without feeling refreshed.

Due to my history of excessive sleeping (and often feeling guilty about it), I’ve become interested in various lifestyle tricks that appear to naturally reduce your body’s sleep need.

Thanks to the volume of email I receive, I’ve come across many anecdotal stories of how one lifestyle “trick” can reduce your brain’s sleep need by 1 to 4 hours per night. That trick is Ketosis.

What is Ketosis?

Ketosis simply refers to when your body uses fat for fuel instead of glucose.

Generally speaking, your body uses two types of energy: fat and sugar. Fat energy come in the form of “ketones”. Sugar fuel in the form of glucose.

Glucose is the “high octane” fuel. It’s efficient and powerful.

The majority of glucose fuel comes straight from the carbohydrates you eat. Since all carbohydrates are either simple sugars (e.g. glucose) or starches (which are just long chains of glucose), the amount of carbohydrates in your diet determines how much glucose you are feeding to your body.

Ketones come from either dietary fat (e.g. olive oil, bacon) or body fat. When glucose supply is high, however, your body switches off the majority of ketone production.

Technically, your body is always producing ketones. So you’re always “in ketosis”. But the phrase “ketosis” is usually used to refer to extreme cases of glucose deprivation, when your body drastically ramps up its ketone production.

If you eat less than 20 grams of carbohydrates per day, for example, your body will have no other option but to enter ketosis.

Ketosis and Sleep

I’ve received a few e-mails from people who, when they follow a low-carb diet, experience a reduced need for sleep. One reader writes:

I have found over the years that my mental acuity is MUCH better when I am IN ketosis vs. when I am not ketosis.

…

On sleeping and ketosis: my natural sleeping cycle while glycogenic is 6hrs @night with one or two  20min naps during the day, my natural sleeping cycle while ketogenic is just over 5hrs @night with one slightly longer nap during the day (30 mins).

Another reader writes:

I sleep probably 5.5 hours a night, without an alarm clock, and sometimes (if I can get away with it) take a 45 minute nap during the day. I’ve not been eating well lately, but when I was doing Atkins, my energy shot up even more and daytime naps were not needed at all.

My fiancé on the other hand, *needs* to sleep 10 hours a day (according to her), often takes naps at any hour and for any reason, and is in general pretty lazy. When she was trying out the Atkins diet with me a few months ago, she was shocked at how she was only needing 6 hours of sleep, and had solid energy from 6AM to Midnight, every day!

Atkins, of course, refers to the popular low-carb, ketogenic diet.

My personal experiences have the same results: When I am more ketogenic, I sleep less — like I mention in The Power Sleep Program, I generally need 6 hours or less per day, quite different from the 10+ I needed several years ago when I was less concerned about what I put in my body. Given that I don’t use an alarm clock (except on occasions) I can only assume that this is a natural decrease in sleep need.

You can also read my other article, Do Grains and Sugar Affect Sleep Duration?

I did some searches on various low-carb online forums and found that the experience of sleep reduction is quite common while on ketosis. This appeared to be either good news or bad news to some people. Some like the idea of having a couple extra hours of alertness per day. Others felt it exacerbated their already-present difficulty in falling asleep. I’m not judging either response, but both were present.

Why Does Ketosis Reduce Sleep Need?

Unfortunately, not much scientific research has been done on the connection between ketosis and sleep (if any — I found nothing in my search). So I can only speculate as to why ketosis might reduce sleep need.

My best guess comes from the idea that brain health is sleep health.

When your brain has lots of available energy, it can conduct the sleep process more efficiently. If you obtain the most important stages of sleep (stage 3, stage 4, and REM) more efficiently, then your brain might need less sleep time overall.

As it turns out, ketosis can be a great way to feed your brain lots of sustained energy.

Ketosis => More Energy for the Brain?

As I mentioned earlier, glucose is the “high octane” fuel when compared to ketones.

Evolutionarily speaking, there was just enough glucose available each day for the brain and muscles. The brain, being a powerhouse of energy consumption (20% of the calories you eat are used by the brain, while weighing just 2% of the total body mass), took up most of the glucose available from plant sources. The rest went to muscles. Remember, humans went 2.5 million years without grains, legumes, or sugary dairy products. Ketones fueled the heart, kidneys, etc.

In today’s world it’s not uncommon to consume large amounts of carbohydrates per day. The typical American averages around 400 grams (though often more). This overload of high octane fuel can burn out cells, including brain cells, leading to poor glucose metabolism.

(That is: The insulin roller coaster caused by the modern diet eventually forces brain cells to become resistant to insulin, thus allowing less glucose to be used.)

Poor glucose metabolism will leave some brain cells unable to fire.

The good news is that the brain can use both ketones and glucose for fuel. The availability of ketones can reduce the brain’s daily glucose requirement down by 60%, or down to about 25 or 30 grams.

The only problem is that ketones have to be present (in large enough amounts) for this benefit to occur, and they can only be present when you’re in ketosis.

This might be why many people experience improved mental clarity (and reduced sleep due to improved sleep quality) while on a low carb diet.

The presence of ketones will help more brain cells fire --> more mental energy and better sleep.

How Much For Ketosis?

How many carbs per day are you allowed for your body to enter ketosis?

It depends.

0 – 50 grams per day will put you in ketosis. 50 – 100 grams will put you in partial ketosis. 100 – 150 grams is a nice balance, where most glucose is used for the brain and muscles, but the remaining organs use ketones (as per their preference).

The actual numbers change depending on your activity level. Lots of exercise will use whatever glucose/glycogen available, which means more ketones must be produced for the brain.

All the foods you’ve eaten in your lifetime also affect the numbers. Has a high-grain/sugar diet in your upbringing caused a severe level of insulin resistence?

And, of course, genetics and your overall “metabolism” affect the numbers. Some experts believe that some people have “carb-type” metabolisms, perhaps from ancestry ranging back to locations near the equator, where plants were available year round; others might have “protein-type” metabolisms — their ancestors might have lived in northern tundras, where meat was the only option for survival during winter months. I’m not 100% sold on this theory, but it might have validity.

And lastly, the type of carbohydrate matters. Carbs from fibrious fruits and veggies affect the body differently than, say, the sugar found in Coca-cola’s latest health gimmick, “Vitamin Water”.

The Catch

Entering ketosis isn’t exactly easy for the first week or two. You may experience headaches, irritibility, or even anxiety. Your body has to adapt to a new metabolic mode, and it doesn’t come without its share of growing pains. During the first week or two of ketosis, your gene expression is changing, your brain cells are adapting to a second source of fuel, and your hormone and neurotransmitter levels are re-stabilizing (serotonin levels, in particular, go through a rehaul when you change carbohydrate consumption).

(Oh, and did I mention that fighting those sugar cravings isn’t exactly easy?)

Some people might say that ketosis is therefore dangerous, that you should listen to your body and bring back the sugar. But keep in mind your body doesn’t always know what’s right for it. The symptoms associated with nicotine withdrawl don’t suggest that you should listen to your body and start smoking again. Same goes for sugar.

Is Ketosis Worth It?

The ketogenic state is advantageous for some people, but not for all.

Ketosis is useful for those who are looking for aggressive weight loss; It might be temporarily necessary for those with diabetes; And it might be a good short-term dietary choice for those looking to fix poor glucose metabolism.

Overall, however, there’s one huge, unavoidable caveat: to enter ketosis you must limit the nutrient-rich fruits and vegetables, which I believe should be the base of any healthy diet.

That’s why I believe you should eat 100-150 grams of carbohdryates per day from plant sources — get the nutrients from plants without overloading your body with high-octane glucuse. For me, the occasional ketogenic diet is used to lose a bit of fat if I’ve fallen off the wagon.

Other Benefits of Ketosis

Ketosis might be worth trying if you want a bit of extra mental clarity and/or reduced sleep need. Of course, these benefits might only appear after a week on the diet.

To end this article, here are a couple other ketosis benefits I’ve picked up from various sources:

• One of the primary indicators of Alzheimer’s Disease is poor glucose metabolism. Feed your brain some ketones and you may be protecting yourself from cognitive decline.
• The most obvious benefit is massive amounts of fat loss. Great for getting rid of belly flab and letting your muscles show.
• It’s a great way to overcome a sugar/carb addiction. Living free of addiction is extraordinary, and sugar is perhaps the most addictive substance in the common diet. Sugar cravings are controllable, but only if you train your body to function without it. (I’ve got nothing against the occasional treat. I’ll gladly take a slice of gluten-free cake on my birthday.)
• It’s also a great way to train your body to function on less frequent meals. Food cravings ever 3-5 hours is really your body screaming to replenish its glucose supply — it’s not so much the food you crave, but the carbs. It’s strangely convenient to live life without the next meal constantly on your mind.

But, of course, your mileage may vary.