Being Tired on a Ketogenic Diet

Does the Keto Diet Make you tired?

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There is a lot of anecdotal evidence that the Keto Diet can make you feel crazy tired, but does it?

From my personal experience and from coaching hundreds of keto clients, I can answer this question with confidence.

Yes, the Keto Diet makes many people feel really tired.  

Most people experience tiredness when they are first starting keto and when they cheat on keto. With time, however, Keto will give you more energy than you ever imagined.

While being tired may be common when starting Keto, there might be ways to reduce this tiredness.

Why are you fatigued when you first start keto?

During the first week of a keto diet, many people experience extreme tiredness while other people feel they have more energy than ever before.

This tiredness is caused by one of the following or a combination of these causes.

Inefficient Fuel Use

When you first start a keto diet, your body is making the transition from burning carbs to burning fat as fuel. If you lived primarily on carbs for most of your life, your body’s fat burning mechanisms are really rusty and the transition is a little harder.  

The only guaranteed way to get through this is time on a strict keto diet.  Any carb cheating will just slow down the transition, so stay strong.

If you want some outside help, some people report an energy boost during this transition period when they supplement with exogenous ketones. These ketones are part of the sequence your body uses to turn fat into fuel, and having a few extra ketones while you’re getting into ketosis really helps some people.

Mineral Deficiency

A Ketogenic Diet naturally acts as a diuretic, which means you are going to be peeing a lot.  With that you are going to flush out lots of minerals, specifically salt, potassium, calcium and magnesium.  

To complicate the situation, on a low carb diet, your kidneys are going to begin to excrete lots of sodium.

If you don’t replace that sodium and other minerals, you can experience tiredness, be light headed, or even suffer from Keto Flu.

A keto mineral deficiency is pretty easy to correct with supplements to reduce the tiredness and keto flu symptoms.  

In our home, we supplement our water and coffee daily with Concentrace Mineral Drops.  Just a few drops in each cup to get the full dose of 40 drops throughout the day.

We also add extra salt to our food, and if we’re feeling light headed or particularly tired we’ll even add a little to our water. We use a high quality Himalayan Pink Salt that has more minerals than just sodium.

Not Enough Calories

The fat in a ketogenic diet is very satisfying, and some people just aren’t hungry.  If you are not eating enough fuel, you could be starving your body and experiencing fatigue.

Yes, it’s true that in ketosis you’ll be burning your body’s fat stores, but that does take a little more work than burning the fat that you eat.  

Your goal is to find the balance that works for you between burning dietary fat and stored fat.   

Maybe try upping your dietary fat for a few days and see how that affects how you are feeling.

Too Much Exercise

You can absolutely workout while following a Keto Diet, but in those first three weeks, while you’re learning how to efficiently burn fat as fuel, your normal workouts might just be too much.

A few weeks of lighter workouts are not going to do your fitness in, and your new way of eating is going to have you crushing your workouts in just a few short weeks.  

Just back off a little on the workouts and see how you feel after three or four days.  

Once you’ve fully made the transition into a fat burning machine, then you can ramp your exercise routine back up.

Why do carbs make you feel tired on a Keto Diet?

Making the transition from burning carbs to burning fat is a learned skill that gets better with practice.  After you are fat-adapted, an occasional carb load is a good thing to give your body that practice making the transition.

However, for many people, those early practice sessions are accompanied by extreme fatigue.

This carb fatigue is caused by the spike, and eventual crash, in both glucose and insulin, that eating carbs naturally causes and that a fat-based diet avoids.

As you get better at making the transition, your body will naturally begin to moderate the spikes and crashes and the fatigue you are experiencing will begin to lessen.

There’s no secret tip to avoid this carb fatigue, just expect it and avoid operating heavy equipment after your carb cheat day. With time and practice, this will get a lot easier.


Experiencing tiredness when you begin a Ketogenic Diet is natural and nothing to worry about if it’s not too severe.  If it is severe fatigue, seek your medical professional’s advice.  I am not a doctor, and I don’t give medical advice. I share my personal experiences and those of my clients for your consideration.

If you found this article valuable, please leave me a comment below and share this article with family and friends.  Those comments and shares make all this hard work worth it.

Finally, if you are just starting keto and struggling, please take a moment to check out my No Cook Keto Meal Plan.  I designed it to be the easiest way to start keto, and I’m very proud of it.

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If you need a Fully Customized Meal Plan, you should consider my sponsor, Custom Keto.

If you need a stupid simple Keto Meal Plan, you should consider my own No Cook Keto Meal Plan.


Disclaimer: While I have been keto for over a decade and have guided thousands of people through starting a keto diet, I am neither a licensed nutritionist nor a medical professional. I never prescribe diets.  I only share my personal experiences and those of my clients for informational purposes only.  Nutrition details are provided for informational purposes only, and should not be considered medical nutritional data. You should consult your medical professional before making any major changes in the way you eat.

Angela Davis

I'm Angela Davis, Co-Founder of Advantage Meals. I have a Bachelors in Anthropology and Masters in Holistic Nutrition. My passion is Ancestral Nutrition and for over a decade I've been helping Keto Diet beginners and those looking for their Primal Diet. "There is no one right way." Below are the most recent articles I've written for

One thought on “Being Tired on a Ketogenic Diet

  1. I am 2.5 years in on keto but stalled for the last year. I do feel tired after cheat days. I struggle with energy but some days I feel loads of energy. I suffer depression and anxiety as well and sometimes it’s hard to differentiate between tired and chemically imbalanced. I will practice this diet due the rest of my life though. I haven’t had the mineral drops in awhile. Think I’ll add these back. Great article. Thank you. 😊

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