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Home Keto Diet Keto Fatigue: Why am I Exhausted On the Keto Diet?

Keto Fatigue: Why am I Exhausted On the Keto Diet?

Keto Fatigue: Why am I Exhausted On the Keto Diet?

The ketogenic diet, also called the keto diet, is an effective diet for weight loss.  Science has shown that keto also supports cardiovascular, neurological, cellular, and metabolic health. However, it’s not uncommon for people on the keto diet to feel tired all the time, and if you are, then you might feel as though you’re doing something wrong or that keto is bad for you. 

In this article, we’re going to take a look at some of the common causes of tiredness and low energy in people who are on the keto diet.  We’ll also discuss how you can fight the fatigue that can come from the keto diet and how you can feel your best while still experiencing the benefits of keto. 

Read on to get the answers you need!

An introduction to keto

The ketogenic diet is a high fat, low carb, and moderate protein diet that focuses on the idea of reaching ketosis – a unique metabolic state. When the body is in ketosis, it is said to increase its effectiveness at burning fat to produce energy. 

The whole premise of keto is using fat to fuel the body: fat is converted into ketones as a primary fuel source. 

You’ll often find people comparing the ketogenic diet to the Atkins diet, though the two differ in their approach to the intake of fat. Keto puts more emphasis on eating healthy fats than the Atkins diet does. 

What’s more, many people fail with the keto diet because they don’t know how to do it properly. If you feel like you’re failing at keto, then you should also consider the Keto Cycle. It’s a great app that helps people follow keto effectively and in a way that is healthy.

So, why is keto causing you to feel tired all the time?

Why am I exhausted on the keto diet: 5 main reasons

There’s actually a number of answers to this question, though most of the reasons that keto can cause fatigue are, thankfully, easy to solve. 

#1 Dehydration

When you consume carbohydrates, your body turns those carbs into sugar and introduces the sugar to your bloodstream. Your pancreas produces insulin in response so that your blood sugar levels don’t spike. 

When you are on the keto diet, or any low-carb diet for that matter, your levels of insulin stay very stable but very low. You are not eating sugar or carbohydrates, so your body has no reason to produce lots of insulin. 

Of course, like many of the body’s functions, insulin doesn’t only stabilize blood sugar. It is also responsible for causing the kidneys to keep potassium, sodium, magnesium, and a variety of other electrolytes. Essentially, when you are on a low-carb diet, the body releases far more electrolytes and water. 

This means that you are able to salt your food without worrying about your blood pressure, though it also means that if you aren’t replenishing your electrolytes, you can quickly become dehydrated. As you likely already know, dehydration causes brain fog, fatigue, muscle cramps, and a plethora of other issues. 

Because of this, many people on the keto diet opt to take electrolyte supplements and drink plenty of water. 

#2 Low food quality

Not all keto food is the same. There are plenty of processed keto snacks out there that, while they technically fit into all of the keto macros, are not very good for you. If you are eating nothing but sugar-free frosting and pork rinds all day, you are going to run out of energy while on keto, even though your body is experiencing ketosis. 

Rather than eating ‘dirty’ keto, you should try your best to prioritize high-quality proteins like fish and steak, fresh vegetables, and lots of healthy fats. 

#3 The keto flu

The keto flu is one of the most common causes of fatigue on the keto diet. When you first start out on keto, your metabolism is forced to change from burning carbohydrates for fuel to burning fats for fuel. This is a significant change in the metabolism, and your body will need a few days before it can start using fat efficiently as its primary source of energy. 

During this period of adjustment – often called the keto-adaptation – you could experience headaches, fatigue, and other minor symptoms. It only takes a few days for your metabolism to start burning fat effectively, so you’ll only experience the keto flu for about a week. 

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#4 Intense exercise

There’s a lot of debate around the interaction between exercise and the ketogenic diet. While many people tend to do just fine in their workout regiments when they are on keto, others run out of energy and observe a decline in their exercise performance and energy levels when they are consuming carbohydrates. 

If you are on an intense workout plan while also being on the keto diet and you find yourself becoming fatigued quickly, you should consider incorporating carbs into your diet again in a way that is targeted and won’t interfere with your ketosis too much. 

#5 Caloric deficit

Ketosis suppresses your appetite, which makes it easier for you to maintain a caloric deficit during the day. It also quickens up the metabolism – you actually end up burning an additional 300 calories per day when you are on the keto diet. 

When you are on keto, your body is basically burning more fat while not feeling as hungry as you normally would. These changes in the metabolism are what make keto such an effective diet for weight loss, but it also means that it is much easier to undereat when you are on keto. 

While mild caloric deficits are good for achieving sustainable weight loss, you might be dipping too low on your calories without even knowing it. Undereating reduces the production of the thyroid hormone in your body, as well as other energy hormones. Over time, this can cause your metabolism to, for lack of a better word, crash.

Not eating enough will leave you feeling fatigued all the time and is quite a common problem for those who are just starting out on the ketogenic diet

How to avoid keto fatigue

By making a couple of changes to your lifestyle or diet, you stand a good chance of getting your energy levels back to normal and start feeling great while in ketosis. Let’s look at a few ways that you can avoid exhaustion while on keto. 

#1 Eat more fats

When you follow the keto diet, most of the energy that your body is using will come from fat calories in the form of stored body fat, as well as the dietary fats that you eat. However, similar to the unhealthy mindset of low calories, people who are just starting out on the keto diet often have an aversion to eating fats

We’re sure that you can guess what happens when you are afraid of eating healthy fats on the ketogenic diet – the same diet where fat is your primary source of energy. That’s right: with a lack of fuel in the form of fats, you are going to experience fatigue. 

If this sounds like you, then you might be delighted to know that fat doesn’t make you fat. So, try to make sure that you are eating enough healthy fats in all of your ketogenic meals. 

#2 Consume more calories

If you have tried any other low-calorie diets before, it’s possible that you are not going into keto with the right mindset. Evidence has shown that people often lose weight and burn fat on the ketogenic diet without counting their calories or restricting them intentionally. 

Even if weight loss is one of your goals, you should try to experiment with taking in more calories to improve your energy and battle exhaustion. Try to eat healthy, keto-friendly whole foods for the next 2 – 4 weeks, and let your appetite guide the amount of food you consume. 

It might surprise you how quickly your tiredness disappears without slowing down the rate at which you lose weight. And, if you are worried that your metabolism is slow, don’t be – it’s generally not an issue when you’re on the keto diet. 

#3 Say goodbye to ‘Dirty Keto’

Dirty keto is an approach to the diet that conforms to all of the keto macros but allows you to eat a lot of foods that are unhealthy. As you can imagine, eating fast food and processed foods that fit into the keto macros exposes your body to synthetic flavors, colors, and unnatural additives. 

Over time, it can also cause imbalances in your omega 3 and 6, as well as vitamin and mineral deficiencies and other issues that could make your fatigue worse. If you have been following dirty keto, clean your diet up and watch as your fatigue vanishes. 

#4 Eat regularly

Beyond your intake of fats and calories, your meal schedule may also have an effect on your level of energy. Eating regularly is one of the best ways to provide your body and brain with plenty of energy, especially if you are just starting out with keto and are not fully fat-adapted yet. 

What’s more, while there is more than enough evidence supporting intermittent fasting, it is not effective for everyone. Try to eat a minimum of three meals each day at first, distributed evenly throughout your day. If this doesn’t decrease your tiredness, you could also include a few snacks that are high in fats and low in carbs. 

Getting the hang of meal prep can help you eat healthy ketogenic meals without disrupting your schedule. If you get into keto fasting, ensure that you’re doing it in a way that is intentional and structured. 

Don’t randomly skip meals when you are short on time and stressed – doing that will only make your fatigue worse. 

#5 Check your macros

If you find that nothing else is really working, it might be time to consider the bigger picture of your keto macronutrient intake. You should follow the following macros on the standard ketogenic diet:

  • 65% – 80% calories from fats
  • 20% – 35% calories from protein
  • 5% – 10% of calories from net carbohydrates

Not consuming enough protein is a common mistake that people make when following the keto diet, especially for folks who lead busy, active lives. 

If you don’t have a math brain, you can use a keto macro calculator to learn the best macros for your goals. There are plenty of these calculators available online. 

#6 Check your intake of carbs

As we’ve already discussed, the ketogenic diet is very low on carbs. That doesn’t mean that you have to avoid carbohydrates entirely unless, of course, you are following keto to treat epilepsy. For most people, the right amount of carbs is between 30g – 50g of net carbs each day. 

Even if you think that you have gotten in all of your carbs for the day, being fatigued constantly might be an indicator to take a closer look at your carb intake and adjust it accordingly to fit your fatigue level.

You are first going to want to test your ketone levels each day to make sure that your body is actually experiencing ketosis. If you aren’t, then lowering your intake of carbs can relieve your fatigue. 

Regularly testing your blood sugar is another strategy that can also give you some more insight. Some people also benefit from eating more carbohydrates, and if you are following a standard ketogenic diet, then keto-friendly vegetables and fruits are your best sources of carbs to make sure that you are staying in ketosis. 

If you are an athlete or just live a very active life, you can use the cyclical keto diet or targeted keto diet to address your exhaustion and provide your body with the energy it needs to sustain long-term physical activity without feeling overloaded or exhausted.

We also prepared a video about 10 signs of ketosis:

Written by
Edibel Quintero, MD

Edibel Quintero is a medical doctor who graduated in 2013 from the University of Zulia and has been working in her profession since then. She specializes in obesity and nutrition, physical rehabilitation, sports massage and post-operative rehabilitation. Edibel's goal is to help people live healthier lives by educating them about food, exercise, mental wellness and other lifestyle choices that can improve their quality of life.

Keto Fatigue: Why am I Exhausted On the Keto Diet?

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