How Much Water Do I Need On A Ketogenic Diet?

Making sure you’re getting in enough water is a good health practice whether you’re dieting or not.

If you are on a low-carb diet like keto, then your intake of water is vital.

We’ll get into the details of why water is so important when on the ketogenic diet, the side effects of dehydration, and the benefits of hydrating well.

How Keto Leads To Dehydration If You’re Not Careful

People tend to overlook how vital water is for a healthy body, but dehydration is a common side effect on the ketogenic diet.

When you consume carbohydrates, glucose is stored in your liver and muscles. When this happens, your glycogen stores in both the liver and muscles build up.

Glycogen is a polymer of glucose. It is made by the liver and muscles, with a typical concentration in humans being about 1% of total body weight.

It can supply energy for about thirty minutes to two hours, depending on the person and situation.

In our bodies, glucose is a bunch of molecules of glucose packed together with water. So for every one gram of glucose, there’s an additional 3 grams of water attached to it. 

Glucose basically stores water in our bodies, so you’re signaling insulin to be secreted when you consume carbs.  

Insulin signals to our kidneys to keep sodium and not release it out of the body.

When we restrict carbohydrates like on the keto diet, insulin secretion is kept to a minimum. So instead of keeping sodium, our bodies get rid of it through urine and sweat.

As sodium leaves the body, so does water leading to dehydration if you’re not replenishing yourself throughout the day.

It’s important on the ketogenic diet that you keep your body from being dehydrated and consume more minerals such as salt.

What Can Happen When You Become Dehydrated

If you aren’t paying attention to how much water you consume throughout the day, it can very well lead to dehydration. 

Some symptoms include:

If you are in a constant state of dehydration, your body will feel pretty terrible while on your diet. 

Also, chronic dehydration can cause long-term health issues, so keep your intake to about half your body weight in ounces, and you’ll be sufficient at those levels.

We Need Electrolytes

For our bodies to stay hydrated properly, there are electrolytes that our bodies need. 

When we have low electrolytes, we may experience chronic muscle cramps, fatigue, or an increased heart rate. The three electrolytes our bodies need are sodium, calcium, and potassium.

Sodium is often considered the main electrolyte. This is because it helps regulate your blood pressure. It also helps neural (nerve) impulses travel throughout the body through your neurons.

Electrolytes help maintain the right balance between the levels of acids and alkaline in our bodies. 

Keeping the correct pH balance helps with muscle function and nerve impulses, which, in turn, improves our body’s performance.

While on a keto diet, a lot of salt is eliminated naturally with the foods that are not consumed, so adding sodium to your meals is a must. 

Your Weight Will Fluctuate

Your weight, especially during the first week of keto, will start to decrease. 

In fact, you may notice your weight bounce around during that period, but the majority of the weight loss during that period is going to be your body releasing all the water that’s stored in our bodies. 

As discussed earlier, this is why you want to make sure your hydration levels are high. 

Why You Need To Drink More Water

As your body transitions to burning ketones for energy, you’ll need more water to keep your body a fat-burning machine.

Here are a few reasons why water is so important:

Replenishing Lost Water

When you have a diet consuming carbs, your body will have water stored. As you transition to a low-carb diet, this water will flush out, and you need to replace it with more water to avoid feeling flu-like symptoms.

You Curb Hunger

Usually, when you think you’re hungry, it’s your body telling you that you need more water. By drinking more throughout the day, you’ll be curbing your hunger pangs.

Less Kidney Stress

By consuming adequate amounts of water, it helps our kidneys tremendously. 

When your body starts producing ketones for energy, sometimes these ketones are pushed out of the body. The purpose is so that too much doesn’t accumulate in our bodies. 

When we drink more water, we’re helping our kidneys do the critical job it needs to do to keep us healthy from toxins.

You Metabolize Fat Quicker

Water molecules are required for beta-oxidation. This is the chemical process whereby our body breaks down fat to produce energy. 

When we lose water through sweat, our body responds by slowing down the beta-oxidation process. This slows down weight loss and even causes it to stop altogether in some cases.

By drinking more water, we can metabolize fat much easier. 

How Much Water Should You Drink on Keto?

You should aim to drink about half of your body weight in ounces each day on the ketogenic diet. 

This number will fluctuate depending on the person because everyone’s age, weight, and diet will be different. 

As an example, if you like to do CrossFit 4-5 times a week, your body will require more water to replace electrolytes than someone who doesn’t exercise at all and sits at a desk all week.

You should drink before you get thirsty. A good measure of how dehydrated you are is through your urine. If it’s a darker color, you’ll want to start consuming more water a little more frequently.

If you struggle to take in the recommended amount of water each day, here are a few tips to help you out:

  • Start a morning habit where you drink a large glass of water immediately upon waking. Your body will be very dehydrated after a long nights sleep and doing this right when you wake up is a great practice
  • Get a water bottle that has the ounces written on the side of it so you can see how much you drank throughout the day. Keep sipping!
  • Keep water close by so you’re constantly reminded to drink more as you’re working.


Since you’re going to be consuming less carbs on the keto diet, it’s natural that you will be dehydrated from the loss in water your body will experience.

If you have unpleasant symptoms, you likely need to drink more water and replace the electrolytes you’re missing, like sodium. 

Check with your doctor to make sure your side effects are typical. 

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