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What most articles on cutting carbs don’t tell you

Plus 5 things you need to know about the keto diet in brain injury

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You don’t have a lot of energy and you more than miss your old life — you grieve it. You use the little screen time you have to look up anything that might help your brain recover.

That’s when you find blogs, social media posts, and all sorts of wellness articles saying that if you cut carbs from your diet, your brain will get better, faster.

You look at the list of foods they say to avoid and it’s a lot of your favourite foods. It’s the food you have at family dinners and share with your friends. It’s the food your kid brings home for you after a party. It’s the food that remains one of your few pleasures left in the day.

You don’t want to give these up, but everyone seems to sing the praises of low carb diets saying “I feel so much better!” “My brain fog is gone!” “It’s the best thing I’ve done!”

You’re torn. Avoiding whole food groups just doesn’t seem healthy to you. You’re confused and you start to feel guilty about how you eat…

Sound familiar?

If it does, I just want you to know you’re not alone! It seems everywhere you turn someone has some great testimonial about cutting carbs and going keto. It’s all very alluring and the research is interesting — I get why the hype exists. But I also see the whole picture.

So I’m here to give you what is often left out of the keto craze conversation. By the end of this article, you will have what you need to decide if low carb is truly a good fit for you.


This principle isn’t anything new. Each generation has had some form of low carb diet sweeping the nation. From Atkins, to South Beach, to Paleo, to now Keto.

In brain injury specifically, the interest has to do with how the brain uses energy.

Some brain energy background:

Carbohydrate foods (aka “carbs”) are a big supplier of energy for your brain. Carbohydrate foods are like water running through hydroelectric dams. The moving water is transformed into power, like carbs in your body are transformed into energy. And just like hydroelectricity is one of the top choices for renewable energy, our brain’s favourite source of fuel on the day-to-day comes from carbs.

But what happens when the brain is injured? Well this causes a sort of “energy crisis.” Like, if your brain were a city, your injury would be like a huge storm that knocked down the power lines, leaving many without electricity. Post injury your brain needs energy to heal, but because the power lines are down, there isn’t enough supply to meet that demand.

This has lead people to wonder whether we should look for another energy supplier. That other supplier, in the low carb diet craze, are fats.

if you’re brain were a city, your injury would be like a huge storm that knocked down the power lines

When you don’t eat enough carbohydrate foods, fats break down into chemicals called ketones. Ketones are typically made in your body during starvation. In the power outage analogy, fats then are like a back up generator and the ketones are like the gasoline that gives fuel when there aren’t enough carbs.

It’s pretty neat that our bodies have this built in back up generator. And ketones do have a place in medicine. For example in epilepsy, some types of seizures can be controlled with a very strict low carb diet, aka the ketogenic diet.


So far you’ve learned that carbs are the brain’s favourite source of day-to-day energy. But an injured brain has an energy problem. Fats can lead to ketones, which could be another source of energy for the brain. And a high fat, low carb diet is used in medicine for seizures…

Maybe you’re thinking, “this all sounds pretty good,” and “I often hear people say it works for seizures so it must be good for the brain!” And yeah, that’s all logical.

But for most wellness articles that tout the benefits of the keto diet for brain health because it’s used for seizures, here’s one little oversight that’s often left out:

The ketogenic diet isn’t a miracle for epilepsy.

It doesn’t actually work for all seizures.

In fact, the diet may only work about one third of the time.

And when it does work, it’s not a lifelong lifestyle change. It’s a short term trial.

I know this because for a period of time, I was a dietitian at a children’s hospital working with neurology to administer this diet for seizure control. And above when I said “strict ketogenic diet,” I’m not talking about the keto diet you find on the every day wellness blog. The medical ketogenic diet was started in hospital as there is a risk of life-threatening consequences.

All that to say, when people tell you it’s good because it “works in epilepsy,” know that this isn’t accurate and isn’t a good reason to assume the diet is a fit for all brain injuries.


One of my more recent clients asked me about the keto diet. I had been working with this person for several sessions, so I thought about how this diet might affect their day-to-day life, their finances, their relationships within their family. I reflected on their medications, their health history and their food skills. I considered their priorities and values in life. I talked these over with my client, and they made the decision NOT to try the diet. Because all things considered, it truly would have been more harm than good.

Generally we accept that medicine is prescribed. You get a prescription for meds from your doctor, you get therapeutic exercises from your physiotherapist, you get glasses based on an assessment by a vision specialist… If medical therapy is overseen by a doctor, pharmacist, physiotherapist, or whoever else you may see, then don’t you want your diet therapy to be cared for by a professional as well?

It’s not just food. There are serious side effects to trying a diet that cuts out whole food groups.


When people I don’t know ask my opinion on keto, I can’t give them a very good answer. Just like an optometrist couldn’t give you their opinion on one type of tint or prescription lens. Your diet needs to be a fit for you.

Here are 5 harms of the keto diet you need to be assessed for:

#1 Side effects that could put you at risk of hitting your head again: nausea, lightheadedness, dizziness, fatigue, poor sleep… sound familiar? These are some of the initial side effects you can get when starting the keto diet. Is this diet worth worsening your symptoms? And if you’re already dizzy, anything that could cause you to hit your head again has risks that, in my opinion, far out match any potential benefits.

#2 The diet can mess with other illnesses you may have: jury is still out on whether the keto diet helps with, or even complicates other health issues. For example, a certain type of high cholesterol seems to get worse with the keto diet. In other types of blood lipid problems, some studies show the diet could trigger pancreatitis. It’s recommended that people with heart failure, kidney disease, liver disease, and those who take medications for things like diabetes and blood pressure, be supervised by a medical practitioner when trying this diet.

#3 If you have yo-yo dieted in the past, the keto diet will likely be yet another toss: the keto diet is not at all easy to follow. Most people can’t stay on it for very long. For weight loss, when using diets you can’t keep at for the rest of your life, there’s a solid 95% chance you’ll regain all the weight back, and likely more. Yo-yo dieting messes with your metabolism, which makes it harder and harder each time to lose, and even keep a stable body weight.

#4 Depriving yourself of foods can trigger an eating disorder: when you restrict lots of food, you tend to crave it. When you allow yourself to eat again, your body makes you overcompensate, because your body doesn’t trust you’ll nourish it again anytime soon. This leads to binging. People who go on and off diets have higher risk for eating disorders. This is especially true when low self-esteem and depression are already things you are struggling with, which are common in long term brain injury recovery.

#5 If the diet is not well planned, at best your brain & body will be malnourished — at worst, when you come off the diet, you will be at serious health risk: cutting out a bunch of foods without a very strategic plan will cause deficiencies. And when your brain is so boggled that you have trouble making even a sandwich, plus changes in appetite that may have you unintentionally not eat, you could become quite malnourished. This has lead to bone problems, anemia, and heart problems. Plus, when someone goes from no carbs and malnourishment to all of a sudden eating carbs again, it’s hard on the body, and the heart. A serious syndrome, called Refeeding Syndrome, is a life-threatening issue we used to only seen in ill hospital patients. Now we are starting to see some effects of refeeding syndrome in people who make extreme diet changes.


Maybe right now you’re like “holy crap! I didn’t know there could be serious problems with the keto diet! I mean, everyone seems to be doing it…I thought it was fine, but now I don’t know what to think!?!”

If that’s you, it’s ok 🙂

You’re allowed to be confused. All the popular media makes you think the keto diet is just a safe thing anyone can try and that it’s super easy and good for everyone. But assuming the keto diet is a right fit for all would be like saying daily-dose aspirin is something everyone should do, everyone should wear bifocals, and each person should put on a knee brace every morning (which, of course, none of these are true!)

I told you that by the end of this article, you would have what you need to decide if the low carb craze is truly a good fit for you. What you need is to ask yourself these questions:

  • Am I at risk for any of those 5 harms?
  • Do I have a health care professional who both assesses me AND reviews the harms before telling me to cut out whole food groups?
  • Does this diet fit with other important parts of my life?


Hopefully you now have the information you need to face these keto diet messages and choose what’s right for you. But if you do want more guidance, reach out to me. I will help you like I set up for success that client who asked me about the keto diet not that long ago.

Unlike messages from other wellness blogs, I won’t just put you on a pre-made diet plan because it’s trendy. I consider all aspects of your health — I consider you as a whole person.

Because I know.

I know you’ve already lost so much from this brain injury. You grieve the things you are missing out on. So why needlessly add missing out on your favourite foods as part of that list of grievances?? There is a better way for you 🙂

Best in brain health for all,

Krystal Merrells, RD


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Lapinskienė, I., Mikulevičienė, G., Laubner, G., Badaras, R., Consequences of an extreme diet in the professional sport: Refeeding syndrome to a bodybuilder, Clinical Nutrition ESPEN 2018, 23:253-255

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kNOw Dieting: Risks and Reasons to Stop, National Eating Disorders Association 2005, accessed online 19 Nov 2019,

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  1. Stephanie

    Love your no-nonsense approach from a brain injury perspective that actually takes into account the reduced energy levels we often have and how fad diets affect our lifestyles and social lives.
    Eloquent, refreshing, and insightful as always:)

  2. Mike Sillett

    You are absolutely correct about the ‘Refeeding Syndrome’ showing its ugly face when stopping the KETO diet.
    When I started the diet Sept 12 I had read all about how great it is. I did not hear anything about how terrible it would be when I would decide to end it. I lost 35 pounds from 9/12 to 11/ 23. Good enough for me. Met my goal. So I decided to stop the diet and eat regular things again starting a few days before Thanksgiving. I was in misery from then until now when I am writing this. Stomach / gastrointestinal issues, intestinal shutdown, weakness, dizzyness. It is just today that I do not get intense stomach pain from eating any piece of carb.
    Anyone that espouses the benefits of KETO should also explain that it is hard to get off of it at the drop of a hat.
    Your article is great in that regard.

    Mike SIllett

    • Krystal Merrells

      Yes, and the diet can be terrible for some people when they start it and are on it too! We wouldn’t want to take a medication if it wasn’t prescribed by a qualified health practitioner who did an assessment and reviewed the pros and cons with us. And I believe the same should be true for therapeutic diets. After all, a diet can change the whole physiology going on inside the body, and also impacts our social and emotional well-being. Plus as you mentioned, transitioning off of it can have its consequences if not properly assessed and guided. I’m glad you found aspects of this article validated your experience 🙂

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