You’ve heard keto is supposed to make you feel amazing. But you feel nauseous, fatigued, and just plain awful.
What’s going on?
What’s causing this keto fatigue, anyways?
You went on a keto diet to improve your fatigue. But now you’re more tired than before you started.
Sound familiar?
I see this phenomenon happen regularly. It’s very common in someone just starting out with a ketogenic diet. Fortunately, it’s a relatively easy fix.
There are three specific points you need to be very aware of when you start a ketogenic diet. Be mindful of these and you’ll avoid the fatigue. And no, it’s not the keto flu that’s causing your fatigue. Read on to find out why you are exhausted on the keto diet.
Keto 101
Your body comes equipped with two different ways to produce energy. It’s like you have both a gasoline and an electric engine. Running on glucose can be compared to a gasoline engine. It’s what most people run on. And for the most part, it works.
When you enter ketosis, you turn off the gasoline engine and start running on your electric engine. In ketosis, your electric engine is much more efficient at producing energy for your body with little effort and waste (especially when compared to the gasoline engine). But switching from burning gas to using electricity as fuel isn’t always smooth.
Sometimes, you can feel worse on a keto diet. In this post, I’ll show you the top three reasons you have no energy on keto and how to easily fix them. That way, you’ll be well on your way to overcoming fatigue and reaping the energy production benefits of ketosis. Say goodbye to keto fatigue!
** Please note that I have laid these three reasons out in a specific order. Please move through them in sequential order. They are meant to build on top of each other. This ensures there are no gaps in your keto diet! **
The hidden cause of keto fatigue: #1. Salt Intake
I’ve solved many keto flus with the simple addition of salt to the diet. And it’s not just my opinion that supports this. Research suggests that the addition of salt will help to lower the negative side effects of getting your body fat adapted. (1)
If you’re experiencing keto fatigue, your first step should be to amp up your salt intake. Generously salt all your food to your preferred taste. If you’re still feeling tired, try adding one teaspoon of salt to the first glass of water you drink in the morning. If the thought of drinking salted water makes you gag, opt for 1 bouillon cube dissolved in water per day or 1-2 cups of bone broth (just make sure your bone broth is well salted).
Amping up your salt intake often gets rid of many of the keto-related side effects including:
- Fatigue
- Headaches
- Muscle cramping
- Heart palpitations (the sensation of feeling your own heartbeat)
But sometimes low sodium (salt) is not the problem. If you’ve already tried increasing your salt intake and you’re not feeling any better, it’s time to look at step number two!
The hidden cause of keto fatigue: #2. A low-carb but not quite ketogenic diet
I see this a lot with newly adopted keto diets. And I think it has to do with a lot of the misinformation found on the internet. Some sites will say restricting your net carbs to <50g will put you into ketosis. Others say <40g net carbs. And others say <20g is absolutely essential.
Here’s the deal: There is no perfect number. Everyone tolerates carbohydrates differently. Some can be in ketosis and eat 50 grams of carbs. Others are going to have to be super strict and ensure their net carbs are always less than 20 grams per day. Stop sticking to generalities. Remember, you’re unique. What works for your friend might not work for you.
Your body does everything it can to be efficient. It takes fewer chemical reactions for your body to use glucose for fuel than it does for fat. So as long as you’re consuming enough glucose, your body will use that for energy. In order to successfully enter ketosis, you need to restrict carbohydrates. Doing this depletes your body’s glucose stores and forces it to use fat for fuel.
If you’re eating more carbohydrates than your body tolerates, you’re not going to enter ketosis. Instead, you’ll be in a low-carb but not quite ketogenic state. And for women especially, this is not a comfortable place to be. It’s a common cause of keto exhaustion, hormonal fluctuations, and decreased athletic performance.
To ensure you’re in ketosis, restrict your daily net carbohydrate intake to less than twenty grams per day. I’ve found that at this level, everyone enters ketosis. When you start going above twenty grams, some of you will inevitably exit ketosis and enter the realm of low carbohydrate (but not ketogenic) diets. This is not where you want to be!
I strongly encourage you to track your macros with an app like cronometer or my fitness pal when you’re getting started. Twenty grams of carbohydrates is not many. And getting nearly 80% of your daily calories from fat is far from intuitive. For the first few weeks, use a tool to objectively measure and track your progress. Do not rely on how you feel. How you feel is highly variable. When you’re starting a ketogenic diet, you need to be objective!
I recommend you avoid carbohydrate re-feeds or any sort of deviation from the keto diet for the first six weeks. These six weeks are all about getting you fat (keto) adapted. It’s likely your body has run on glucose for the majority of your life. Getting your fat-burning machinery well-calibrated will take some time. So, for the first six weeks, be super strict with your keto diet.
This should help you improve your fatigue levels. But if both steps one and two still didn’t provide the keto fatigue cure you were looking for, read on to step number three.
The hidden cause of keto fatigue: #3. The accidental low-calorie diet
Of all the potential reasons you feel tired on a ketogenic diet, this one is by far the most insidious. I see it happen time and time again in the clinic. And it’s an honest mistake. It’s happened to me on more than one occasion.
When you’re in ketosis, the hunger signals that arrive at your brain are not nearly as loud as they are when you’re burning glucose for fuel.
You’ve been hangry before, right?
When you’re hangry, your brain is screaming at you to eat. You’re absolutely miserable. The world is irritating when you’re hangry. This is a strong hunger signal caused by low blood sugar.
But when you’re in ketosis, the hunger signal can be a gentle whisper. This makes it really easy to ignore. The reason the ketogenic hunger signal is so subtle is that your brain (and other energy-consuming machinery in your body) have constant access to your body fat. All of us carry at least some body fat. So, there’s always calories to be had.
When you burn glucose for fuel, you’re dependent on eating to get enough energy. But when you’re in ketosis, your body can always steal some energy from your fat stores. That’s why the hunger signals from ketosis can feel more like suggestions than actual impulses.
Since these reminders to eat are both infrequent and subtle it’s not at all uncommon to be extremely deficient in calories and not be hungry. I had a patient complain of intense fatigue and lethargy shortly after starting a keto diet. When we calculated her daily calories, she had been in an almost 1500 calorie deficit every day for the past two weeks! And she wasn’t the least bit hungry. At that level of daily calorie restriction, it’s little wonder she was exhausted!
For reference, a healthy weight loss strategy (depending on your height, weight, and activity level) is to decrease your daily calories by about 500. This should result in approximately one pound of weight loss each week. My patient had cut 3x that much every day!
Lots of websites suggest that while on a keto diet, you eat when you’re hungry and eat until you are full. I love this adage. I think it helps to create a healthy relationship with your food. But intuitive eating can make you fatigued when you’re new to keto.
To ensure your daily calorie needs are within healthy ranges, I strongly encourage you to track. I know, counting calories is awful, painful, and neurotic. It is all of these things. But it simply has to be done in the beginning. Otherwise, you may end up on an accidental low-calorie diet! Once you’ve been on keto for a couple of months, you can then move towards intuitive eating.
How to calculate your daily caloric needs
To calculate your daily calorie needs, I recommend using a formula like the Harris-Benedict equation. This will give you a rough approximation of your basal metabolic rate (BMR). Your BMR is the number of calories your body burns in a day – based on your exercise habits and movement levels throughout a normal day. If you eat close to this number, you’ll maintain your current weight.
If you’re following a keto diet to improve your energy but also want to lose weight, I don’t recommend you cut your daily calories any more than 500 calories less than your daily BMR. This should keep your energy levels high and result in a weight loss of approximately one pound per week.
If you don’t need to lose weight, try to keep your calories close to your BMR. This becomes very important for those of you who are quite lean. There’s just not enough extra adipose tissue on your body to use as fuel.
If you’re practicing intermittent fasting, you’ll need to be mindful of your total calories consumed in a week. On fasting days, you’ll be well below your BMR level of calories. That is just fine so long as you make it up on non-fasting days (eating more than your BMR suggests). For some of you, intermittent fasting is only going to decrease your energy. If you don’t feel good fasting, don’t do it.
After you’ve got a rough idea of how many calories you need in a typical day/week, you can stop with the counting. Move back towards intuitive eating – eat when you’re hungry. Eat until you are full. But only do this after you’re confident about how much you need to eat in a typical day/week.
One last hidden cause of keto fatigue
If you’re still struggling with no energy on keto, this fourth cause is the hardest to uncover. It has to do with your carbohydrate tolerance. More specifically, you’ll find there to be certain carbohydrates that consistently contribute to your fatigue – regardless of whether you’re in ketosis or not.
I don’t recommend trying to identify what these foods are until you’ve been on a ketogenic diet for at least sixty days. Once you’re keto-adapted, start paying close attention to your energy levels after eating. When you feel tired after eating, make a note of the foods you ate in your meal.
If you start noticing a pattern of fatigue whenever you consume a certain food, you’re on the right track! In all likelihood, it’s going to be a carbohydrate source that causes your keto fatigue. So pay very close attention to all the carbs in your meal.
If you struggle to identify which carb(s) are causing your fatigue, consider my eCourse, Stop Feeding Fatigue. In it show you how to precisely identify exactly which foods cause your keto fatigue and which foods give you energy. After finishing the course, you’ll know your very own ideal way of eating!
Ok, now you know how to avoid keto fatigue. Now, I want to hear from you!
What strategies gave you more energy on a keto diet?
What hidden causes of keto fatigue did you experience?
Want to know more than your doctor about how to overcome fatigue?
Ct says
No one talks about your second point- thank you this was exactly what I needed to read.
Mark Volmer says
Happy I was able to help!
M
Anton says
Started feeling really sleepy on my 3rd week of keto. Turns out the cause was me adding a bit more carbs, thanks!
Mark Volmer says
Hey, Anton,
Those carbs sneak up on you quickly! And they make you super sleepy.
High fives for figuring it out 🙂
M
Ren says
Will magnesium as a supplement also helps? I feel so drowsy and had headaches on my first week.
Mark Volmer says
Hey, Ren!
I think magnesium is essential to supplement. But your drowsiness and headaches may have more to do with the keto fatigue causes I list in the post! Try them first. If that’s no help, add some magnesium glycinate!
M
Fernanda says
Wow! My boyfriend and I have been keto for 2 years, this week we started feeling super fatigue! A cup of water with one tbsp of salt fixed it! Geez! We supplement magnesium and potassium, but never felt the need of adding more sodium to our daily intake! TY! 🙂
Candice Trott says
Hi
I started keto June 1
I take magnesium daily, salt my food and have taken salt shots.
Nothing is working I still am tired and no energy.
My kitchen is on the lower floor and it exhausts me to walk up the steps and to do housework.
I use carb manager to track what I’m eating. I stay around 20 carbs or less daily. My fat I hit almost. But I struggle to eat that much protein. I have never been a big eater, and on keto I’m hungry rarely.
I suffer from headaches, keto Rash, muscles cramps and fatigue, dizzy and low blood pressure.
Taking bile salts for keto rash
I don’t eat the 0 carb breads because of wheat intolerance.
Upped my vitamins. Drink lots of water
I’m going to up my carbs a bit because I can’t continue feeling this way anymore..I have things to do and feeling exhausted every day is not working for me
Mark Volmer says
Hi, Candice,
This sounds to me like there’s more going on than just keto-related fatigue.
Check out my article on chronic fatigue and mold – https://fatiguetoflourish.com/chronic-fatigue-symptom-of-toxic-mold/
M
meka says
Thank you I’ll try this. I’m so, so tired it hurts even to move and have sych a headache, ugg.
Jacqui Lytle says
Thank you for the article. It’s great information. I’ve reached my goal weight with Keto but don’t know how to transition. I think I might be stuck in that low-carb but not ketosis phase that you describe. I don’t want to stay under 20mg anymore because I don’t want to lose more weight but whenever I “cheat” or just add more carbs, my weight goes up, then I lower the carbs again and have NO energy! Suggestions?
Mark Volmer says
Hey, Jacqui,
Frustrating.
I think carb cycling is the solution for you! Pick 1-2 days per week where you indulge in healthy carbs followed by 5-6 days of strict keto.
M
Lynn Reichenbach says
Have foot cramps at night. Was so tired last night went to bed at 8. Found your site and putting more salt on food and drinks. Also my heart was pounding out of my chest this am. Been on Keto for one month. Will a cup of keto cocoa be good to drink
Pam hickman says
How does keto work for diabetics? I have just finished one week experimenting to lower blood sugar and weight. I lost 6 pounds and my glucose readings have improved. Now I am experimenting fatigue and nausea. I am new to the research, so I’m not sure what to do. Do you have any information that pertains to diabetics?
Pam
Mark Volmer says
Hey, Pam!
Keto is amazing for diabetics. Just make sure you’re under the care of a knowledgeable practitioner.
I’d recommend reading a book called End Your Carb Confusion. It’s a great resource for all things keto and diabetics.
M
Mark Volmer says
Keto cocoa is just fine.
But make sure you’re getting your electrolytes! And salt everything 🙂
M
Andrew says
It takes time (6 weeks) to get fully fat adapted, so why would anyone want to cycle in carbs to take themselves out of ketosis and then have to go through the headaches and fatigue again to get back into ketosis? My experience over the last 3 years in ketosis has been that the more strict I am about it, the better I feel. My wife and I went on an anniversary vacation recently and I made the mistake of eating a bunch of fish tacos over the week, and totally took myself out of ketosis. I’m now 1 week back into my nearly 0 carb program / borderline carnivore (eggs, steak, cheese, avocados, etc.), 3 days ago had the headaches that I had 3 years ago, and now I’m going through the fatigue phase again. Bottom line is – stick through the difficult phase to get to the good stuff (clarity, energy, autophagy).
Sarah says
Hi, I’ve been keto for 7 weeks now, first 10 days were tough then I felt good but think I ended up doing what you describe above and didn’t quite get enough calories and felt awful fatigue and sluggish, I ate some carbs here and there and went at it again with the keto, started to feel good again but today the horrible fatigue came back and I had some carbs as I just couldn’t get satiated on the keto food today. I haven’t lost as much weight as I’d like but I’m pretty confused about how best to proceed… is it too soon for me to carb cycle?
Mark Volmer says
What are you doing for electrolytes, Sarah?