Why is my ME/CFS Worse on a Keto Diet?

Why do I feel worse on a keto diet? My chronic fatigue syndrome is worse on a keto diet.

I first wrote about ketogenic diets for ME/CFS back in 2015. Maybe you’ve tried a ketogenic diet since. Some have reported major benefits. Others though may have given up on it quickly due to some adverse effects. In this post, we review the diet and common side effects that may occur.

A ketogenic diet is composed of high dietary fat that is the main source of daily calories, and also severely restricts carbohydrates. This equates to a total carbohydrate intake of less than 50 g/day and a protein intake at least 1.5 g/day/per kg of body weight. The remaining caloric intake comes from fats and should be around >80% of total calories.

The body’s metabolism is highly flexible. With a ketogenic diet as described above, metabolism shifts to fat burning and stimulates the liver to produce ketones. These ketones have various effects on the brain, gut, and mitochondrial function as described elsewhere.

However, not everyone with ME/CFS or Fibromyalgia has responded favorably to a ketogenic diet. In fact some report worsening symptoms. Let’s look at some common reasons why it may not be working for you, or why the diet makes you feel worse.

Water Loss

During the initial stages of ketosis the body rapidly breaks down stored glucose which is formed as glycogen. The glycogen molecule is stored in a hydrated form within skeletal muscle and liver. The quick breakdown of glycogen therefore also results in rapid water loss in the urine. This is commonly known as loss of “water weight.”  These rapid losses of water can predispose to dehydration. Increasing your water intake substantially during the first few weeks of a ketogenic diet are imperative. Because water always follows salt in the body due to osmosis, salt will also spill into urine during these loses. The rapid water and salt loss can result in light-headedness and dizziness upon standing. Drink more water and add more salt to meals.

Electrolyte Deficiency

Nausea, vomiting, headache, fatigue, dizziness, insomnia, constipation. Adverse effects as these are sometimes referred to as the keto flu. All of these effects may be explained by losses of potassium. In addition to water, stored glycogen also comprises a large surplus of potassium. Potassium is therefore also lost through the urine as glycogen is depleted. Consider a supplemental electrolyte drink in the initial weeks of trying this diet. Continue to eat non-starchy fruits and vegetables as these are excellent sources of potassium.

Macronutrient Deficiency

Ketogenic diets are not always nutrient dense. While they should still include non-starchy vegetables, they may still be inadequate in the essential nutrients of a standard diet. The literature shows that ketogenic diets are low in calcium, zinc, selenium, and copper. A general multi-vitamin, multi-mineral supplement is suggested as long as one is on a ketogenic diet to cover these inadequacies. If possible, consume adequate amounts of seafood and shellfish as they are the richest food sources of these nutrients.

Kidney Stones

If there is a family history or past history of kidney stones, caution is suggested before starting a ketogenic diet. It has been reported that up to 6% of those who try a ketogenic diet develop kidney stones. Those with hereditary risk factors may consider adding supplemental citrate to reduce the risk of kidney stone development. However, careful monitoring with a nutritionist is suggested.

Chemical Toxicity

Several environmental pollutants are preferentially stored in fat tissue and released into the circulation during rapid weight loss. During the early stages of a ketogenic diet when weight loss is also experienced, there may be a steady release of these pollutants which can have various ill effects. For example, polychlorinated biphenyls (PCBs) as well organochlorine pesticides are well studied to be released during weight loss. These chemicals are implicated as potential endocrine disruptors and obesity stimulants. In some studies, the elevated organic pollutants are still in circulation up to 12 months following the initial weight loss. Supporting liver detoxification pathways with sulphoraphane is one of many possible approaches in these cases.

Worry not.

In general, adverse effects of a ketogenic diminish over time. Some never experience any of the above symptoms at all. After 3-4 weeks, the body will adapt to use ketones as a primary fuel source in a process known as keto-adaptation. Also worth noting, after keto-adaptation there is no longer rapid depletion of glycogen stores. Despite low carbohydrate intake, skeletal muscle and liver will continue to store glucose made de novo by the liver. Many of the ill effects that can occur in the initial stages of this diet are due to this initial glycogen depletion and will therefore reduce after ketoadaptation.

What has been your experience on a ketogenic diet? Tell us in the comments.


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