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Why Ketones (and Ketosis) Can Cause Stomach Pain


This is not a “feel-good” post. We are going to talk about some of the not-so-pleasant side effects of transitioning into ketosis, especially looking at why ketones (and transitioning to ketosis, in general) can cause stomach pain. We will also talk about what you can do to solve the issues. Some are practical solutions; others have to do with summoning the mental strength to just deal with a little discomfort to get the rewards and results you want.

If Captain Jack Sparrow were doing the ketogenic diet, he would probably say. “The stomach pain is not the problem… it’s your attitude about the stomach pain which is the problem.”

I’ve been there too. The first time I ever tried exogenous ketones, I was about 16 hours removed from carbohydrates (In-N-Out burger) and I was feeling awful. I thought Perfect Keto would make it all better. I took a heaping scoop of Chocolate and waited 30 minutes. The results? Significant stomach issues, to put it kindly. I thought surely these ketones are bad and I quit my attempt to “go keto” on the spot.


Why Ketosis Causes Stomach Pain

The short answer is dehydration. The process of keto-adaptation is going to dehydrate us. Remember that one purpose of taking exogenous ketones is to speed up keto-adaptation. This means taking ketones will also speed up the side-effects of keto-adaptation.

Why Does Ketosis Dehydrate?

Transitioning to keto means we are moving from using glycogen and carbs to using fat and ketones. There are two reasons this dehydrates us.

1) One of the main inefficiencies with glycogen and carbs is that it must be stored with water. It takes 4 grams of water to store a gram of glycogen.[1] As you run through your glycogen you will lose tons of water (not literally tons but you get the point).

2) High insulin levels (on high carb diets) cause water retention by inhibiting sodium excretion[2]. The keto diet lowers insulin levels, allowing excess fluid to be released.

Add these together, and we have the symptom of stomach pain. Other symptoms will include headaches, lethargy, nausea, brain fog and low motivation.

How to Cure Your Stomach Pain

Back to my story that the first time I tried keto and felt a little discomfort, I gave up immediately. Soon after, I did a little more research and found out that there are simple cures to the symptoms I was feeling. Also, it turns out the symptoms are incredibly common. Nearly everyone who does the ketogenic diet experiences the same symptoms at some point. It is so common that there are literally memes all over the internet about stomach pain when transitioning to ketosis (and they are awesome).

The cures are simple and fall into two broad categories: practical, and mental.

Practical Cures to Stomach Pain

Water – Drink an incredible amount of water. When you feel you have had enough, drink even more.
Salt – Add salt to your foods and drinks wherever possible.
Time – Remember, time takes time.
More Fat – Eating a ton of fat already? Good, eat even more. You don’t want to be low on energy (fat) during the transition.
Slowly Ramp up Exogenous Ketones – Don’t crush a full scoop the very first time like me.

Mental Cures to Stomach Pain

Remind yourself why you are doing this – Isn’t it interesting that all the symptoms we deal with are actually the inverse of the rewards we are seeking? Fatigue will be replaced with energy, brain fog will be replaced with extreme focus, low motivation will be replaced with a heightened sense of well-being.

Remember this is common – keep going, do not worry, and don’t play the victim and give up.

Dig deep – Again, don’t give up at the first slight discomfort like I did. Dealing with some pain is not going to kill you.

It’s remarkable that a little bit of stomach pain has very quick easy fixes, but it caused me to do something irrational, like give up. There is a deeper problem at hand as Captain Jack alluded to – it’s called rationalization.

The Issue Behind the Stomach Issues

Yes ketones and ketosis cause stomach problems, but the real problem is that it causes many people to quit or assume ketosis isn’t for them, or the diet sucks. Enter rationalization. This is the process of taking something irrational (my tummy hurts, therefore I’ll give up) and making it “rational” (this diet is not for me, and perhaps dangerous, and exogenous ketones are bad).

How to Deal With Rationalization Rationally

The first step would be to just notice your internal thought process at work. Instead of looking for simple cures like drinking more water, or adding more salt, or giving it some time, your head might be flying off a cliff. To deal with the problem behind the stomach problems, move down this list:

Remind yourself it’s normal – Everyone who does the ketogenic diet and takes exogenous ketones experiences this. You are unique, but just like everyone else is unique, too.

Don’t give up – Don’t give up because you are experiencing some slight pain and discomfort. On the other side of pain is the reward.

Check your motives – Why do you want to quit? Why did you start this diet in the first place? Does it make sense, or serve you in any way, to bitch about how you feel and why keto doesn’t work? It would probably make the most sense to see what symptoms you have and deal with them appropriately. Don’t hide a bad motive under a seemingly good motive and sabotage yourself.

Why Ketones and Ketosis Can Cause Stomach Pain


Back to my story, I ended up trying ketosis again and this time I didn’t give up or panic about stomach pain. I drank tons of water and upped the fat and salt and gave myself space to feel a little uncomfortable.

The results are now the side effects I feel are tremendous energy, focus, and well-being. I still occasionally do feel stomach pain, and it is a reminder that ketosis is in action, and I should probably hydrate. 🙂

If you are going to do a strict ketogenic diet and take exogenous ketones, here’s what you can expect:

Initial Negative Side Effects

  • Dehydration
  • Stomach Pain
  • Brain-Fog
  • Low Motivation
  • Irritability

Eventual Positive Side Effects

  • Energy
  • Focus
  • Well-Being
  • Longevity
  • Low Hunger
  • Better Sleep

Do all the practical cures mentioned above – Water, salt, time, fat, and mental strength.

This may be harsh but everyone wants to “go keto” until it’s time to do what it takes. If you want it, get your butt up and make it happen. Use your pain to make a smart adjustment and take yourself to new heights and inspire others.


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