Are Plant-Based Diets Right for ME/CFS, Fibromyalgia, and Long COVID?

When it comes to dietary recommendations for ME/CFS, fibromyalgia, and long COVID, the research often lacks depth and specificity. Many studies suggest a "balanced, nutrient-rich diet" without defining what that balance means—leaving patients searching for clarity.

With the global push toward plant-based diets, it’s easy to assume they’re the ideal choice for chronic conditions. However, for those managing post-viral syndromes, my take is different. Plant-based diets may not be the best option. Here’s why:

Key Concerns With Plant-Based Diets for Chronic Conditions

1. Macronutrient Imbalance

Plant-based diets often fall short on protein while being disproportionately high in carbohydrates. Here’s why that matters:

• Low Protein:
  Protein is essential for maintaining muscle mass, immune function, and hormone synthesis—especially for those with chronic illnesses.

  • Complete proteins, which contain all nine essential amino acids, are rare in plant-based diets. Most plant foods (beans, lentils, nuts, seeds) are incomplete proteins and require careful pairing for a complete amino acid profile.

  • Animal proteins like meat, fish, eggs, and dairy are much richer sources of protein, requiring less volume to meet daily needs.

• High Carbohydrates:
  Many plant-based diets rely heavily on grains and legumes, which are high in carbohydrates.

  • For individuals with mitochondrial dysfunction—common in ME/CFS and fibromyalgia—this can overburden energy production pathways, leading to fatigue and weakness.

The Case Against High-Carbohydrate Diets in Chronic Conditions

Even "healthy" carbohydrates from whole grains and legumes can strain the energy production pathways in those with mitochondrial dysfunction. Studies in ME/CFS, fibromyalgia, and long COVID reveal abnormalities in carbohydrate metabolism, meaning:

• High-carb diets can lead to fatigue, brain fog, and weakened cellular function.

• Instead, prioritizing low-carb, high-protein, and nutrient-dense foods may better support mitochondrial energy production and symptom management.

2. Micronutrient Deficiencies

Certain essential nutrients are naturally abundant in animal foods but lacking in plant-based diets, such as:

• Iron:
  Non-heme iron from plant sources like leafy greens is poorly absorbed compared to the heme iron in animal foods.

• Vitamin B12:
  Critical for energy and neurological health, B12 is almost exclusively found in animal products. Vegans are three times more likely to be deficient than vegetarians or omnivores.

• Carnitine:
  Found in meat, carnitine supports mitochondrial energy production. Low levels can exacerbate fatigue.

• Choline:
  Vital for brain and liver health, choline is predominantly found in eggs and meat. Most people already fail to meet the recommended intake, and plant-based diets increase this risk.

Plant-based diets are depleted in essential micronutrients. Some of the most prominent are iron, zinc, iodine, and vitamin B12. Animal foods are rich in these essential vitamins and minerals. While green leafy plants are rich in iron, this is not heme-containing iron. Non-heme iron is very poorly absorbed in the digestive tract. B12 is often found in the soil of unwashed plants. Washing our produce reduces these soil residues. Vitamin B12 is also fortified in grains (added during manufacturing), which definitely prevents deficiencies but does not necessarily ensure adequate absorption and utilization. Fermented foods can also stimulate our microbiome to make its own vitamin B12. However, again, the quantities pale compared to animal food diets. Vegans are 3 times as likely to be deficient in vitamin B12 as vegetarians and omnivores.

Other essential micronutrients that are depleted in plant-based diets are carnitine and choline. Carnitine gets its name from carnivore since it is abundant in animal foods. The body uses the carnitine in our foods, in the form of acetyl-L-carnitine (ALCAR), to move fats into the mitochondria for breakdown to cellular energy, ATP. Too little carnitine spells fatigue.

Read more about carnitine HERE.

Choline is an essential dietary nutrient for brain, heart, and liver health. Plant-based foods like pinto beans, peanuts, quinoa, and legumes do contain choline. However, animal foods, especially eggs, are the best sources of choline. Those on vegan and vegetarian diets show low levels of choline. The recommended choline intake should be at least 400mg/day for adults. Those with low estrogen, such as post-menopausal women, require more dietary choline intake since estrogen is required to activate choline.

National diet surveys from Europe, North America, and Australia indicate the average person seldom meets choline requirements. Only 11% of Americans meet adequate choline intake. Dietary choline is essential for cognitive function. There is compelling evidence from human studies of negative health outcomes associated with lower choline intake, including fatty liver disease and cognitive decline.

3. Digestive Challenges

• Irritable Bowel Syndrome (IBS):
  Approximately 60% of ME/CFS patients experience IBS, making digestion of fiber-rich, plant-based foods difficult.

• Small Intestinal Bacterial Overgrowth (SIBO):
  High-FODMAP foods (common in plant-based diets) can worsen bloating, gas, and abdominal discomfort in those with SIBO.

Read more about FODMAPs HERE.

4. Increased Effort & Energy Expenditure

• Preparing balanced, digestible plant-based meals often requires:

  • Soaking and sprouting legumes and grains.

  • Creating alternatives like cashew-based dairy substitutes.

  • Managing complementary amino acid combinations to meet protein needs.

• For individuals with low energy reserves, these added steps may not be realistic. Many turn to processed plant-based foods, which often contain additives and chemicals that may worsen inflammation.
  
  

Bottom Line: Are Plant-Based Diets Right for Chronic Illness?

While plant-based diets offer environmental and ethical benefits, they may not meet the specific nutritional needs of individuals with ME/CFS, fibromyalgia, or long COVID. High-protein from animal foods and nutrient-dense diets are better suited to support mitochondrial function, reduce inflammation, and alleviate fatigue.

References

Barrea L, Grant WB, Frias-Toral E, et al. Dietary Recommendations for Post-COVID-19 Syndrome. Nutrients. 2022;14(6):1305. Published 2022 Mar 20. doi:10.3390/nu14061305 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8954128/

Majchrzak D, Singer I, Männer M, et al. B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans. Ann Nutr Metab. 2006;50(6):485-491. doi:10.1159/000095828 https://pubmed.ncbi.nlm.nih.gov/16988496/

Wallace TC, Blusztajn JK, Caudill MA, et al. Choline: The Underconsumed and Underappreciated Essential Nutrient. Nutr Today. 2018;53(6):240-253. doi:10.1097/NT.0000000000000302 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6259877/

Derbyshire E. Could we be overlooking a potential choline crisis in the United Kingdom?. BMJ Nutr Prev Health. 2019;2(2):86-89. Published 2019 Aug 29. doi:10.1136/bmjnph-2019-000037 https://pubmed.ncbi.nlm.nih.gov/33235962/