Carnivore Diet for ME/CFS, Long COVID, and Postviral Conditions

Interest in the carnivore diet is booming, especially among people with chronic conditions looking for dramatic relief. But when it comes to ME/CFS, long-haul COVID, and other postviral syndromes, the carnivore diet may do more harm than good in the long run.

Let’s break it down, starting with an important distinction.

A Carnivore Diet Is Ketogenic, But a Ketogenic Diet Is Not Carnivore

This distinction matters. I’ve long promoted therapeutic ketogenic diets for postviral conditions like ME/CFS and long COVID—not because they’re trendy, but because they target key mechanisms: mitochondrial dysfunction, chronic inflammation, and impaired energy metabolism.

A ketogenic diet is defined by its ability to induce nutritional ketosis, typically through a macronutrient ratio of:

• 70–80% fat

• 10–20% protein

• 5–10% carbohydrates (usually 20–50 grams of net carbs per day)

In contrast, a carnivore diet is an extreme form of keto that includes:

• 60–90% fat

• 10–40% protein

• 0% carbohydrates (no fiber, no plant foods, no polyphenols)

While both diets can promote ketosis, carnivore excludes all plant-based foods, which are essential in a therapeutic keto approach.

A well-constructed ketogenic diet includes:

• Non-starchy vegetables (e.g., leafy greens, zucchini, broccoli)

• Fermented foods (e.g., sauerkraut, kimchi)

• Herbs and spices rich in polyphenols (e.g., turmeric, rosemary)

These are not optional extras. They are critical for:

• Gut microbiome diversity

• Butyrate production

• Reducing oxidative stress and systemic inflammation

• Supporting gut-brain-immune interactions

Eliminating these foods, as the carnivore diet does, risks undermining the very systems that need the most support in postviral recovery.

1. Butyrate Is Already Low in ME/CFS—And Carnivore Makes It Worse

One of the most concerning effects of the carnivore diet in this context is its complete elimination of fermentable fiber, the primary fuel source for butyrate-producing bacteria.

In my blog post on dysbiosis and sleep problems in ME/CFS, I explain how butyrate deficiency impairs deep sleep and contributes to unrefreshing rest. Butyrate is not just a gut metabolite—it crosses into circulation and interacts with sleep-regulating centers in the brain. Studies in animals show it can deepen NREM sleep, and emerging human data suggest it plays a role in sleep quality and recovery.

Butyrate is produced when gut microbes ferment certain dietary fibers, especially resistant starches, found in:

• Cooked and cooled potatoes or rice

• Green bananas

• Legumes (when tolerated)

• Certain whole grains

These are completely absent in a carnivore diet.

In individuals already struggling with postviral dysbiosis, this lack of fermentable substrate can result in:

• Further butyrate depletion

• Poorer sleep regulation

• Increased gut permeability

• Heightened inflammation and immune dysfunction

While reduced fermentation may temporarily reduce bloating, the long-term consequence is microbial starvation—not healing.

2. Cardiovascular Risk Is Real—Especially Without Fiber

Saturated fat is not inherently harmful, but in the absence of fiber and plant compounds, its impact changes, particularly in people with postviral insulin resistance.

Insulin resistance is well-documented in ME/CFS and long COVID. Studies show impaired glucose uptake, elevated insulin, and mitochondrial inflexibility—even in lean individuals.¹,² A 2023 study found that long COVID patients had disrupted mitochondrial fatty acid oxidation and impaired insulin sensitivity.¹

In this context, high saturated fat intake—without the buffering effects of fiber—can increase cardiometabolic risk. Fiber helps by:

• Binding bile acids and lowering cholesterol absorption³

• Feeding butyrate-producing bacteria that improve insulin sensitivity⁴

• Blunting postprandial (after meal) glucose and lipid spikes⁵

People with ApoE4 genotypes are particularly vulnerable. They experience greater LDL-C increases and more inflammation on high-saturated-fat, low-fiber diets.⁶ For postviral patients, this presents a compounded risk, especially when autonomic or vascular dysfunction is already in play.

A well-structured ketogenic diet mitigates this by including fiber, omega-3 fats, and polyphenols. Carnivore excludes them all.

3. Microbiome Diversity Is Already Compromised in Postviral Illness—And Carnivore Starves It Further

Loss of microbial diversity is a consistent finding in both ME/CFS and long COVID. ⁴,⁵ Studies have shown:

• Reduced Faecalibacterium prausnitzii and other butyrate producers

• Overgrowth of Enterobacteriaceae

• Increased gut permeability

• Decreased SCFA production⁶

This dysbiosis contributes to:

• Fatigue and brain fog

• Immune dysregulation

• Mood disturbances and sleep impairment

Rebuilding microbial diversity requires substrates—fuel for gut microbes. In my blog post on polyphenols and essential nutrition for ME/CFS, I explain how polyphenols act as selective prebiotics, feeding beneficial bacteria while inhibiting harmful strains.

Rich polyphenol sources include:

• Berries

• Green and black tea

• Olives and extra virgin olive oil

• Herbs and spices

• Dark chocolate (in moderation)

These compounds, combined with resistant starch and low-FODMAP vegetables, help restore microbial diversity. The carnivore diet excludes all of these tools.

Why Some People Feel Better on Carnivore

Some with ME/CFS, long COVID, or fibromyalgia report dramatic symptom relief on a carnivore diet. But this reflects gut dysfunction, not a need for meat-only eating.

Temporary improvements often stem from:

• Reduced FODMAP load (less fermentation and bloating)

• Mimicked fasting (less microbial byproduct production)

• Simplified digestion (especially helpful with SIBO or low stomach acid)

• Lower histamine/salicylate/oxalate burden (common in MCAS)

These effects offer gut rest, not a fix. A low-FODMAP ketogenic approach or carefully structured elimination diet could achieve similar benefits without sacrificing long-term gut and metabolic health.

Bottom Line: There Are No Shortcuts in Postviral Recovery

Carnivore might offer temporary reprieve, but it’s not a sustainable or safe solution for most with postviral syndromes. A more intelligent approach supports butyrate production and microbial resilience through:

• A low-FODMAP ketogenic diet that includes plant polyphenols

• Resistant starches, tailored to individual tolerance

• Refeeding strategies that repair rather than suppress the microbiome

Short-term carnivore may function as a brief elimination tool, but only if followed by a structured reintroduction phase focused on microbial support. Without this, the risks outweigh the rewards.

A Smarter Path Forward:

• Therapeutic keto + fasting

• Low-FODMAP + polyphenol refeeding

• Microbiome-aware strategies rooted in mitochondrial support

This is where healing begins, not in extremes.

If you’re looking for practical guidance on how to put these principles into action, my online course on advanced digestive health is designed specifically for people with ME/CFS, long COVID, and similar conditions. It covers:

• Symptom-informed elimination diets

• Gut healing protocols for dysbiosis, SIBO, MCAS, and more

• Step-by-step reintroduction strategies to support butyrate production and microbiome diversity

👉 Learn more about the course here —designed for low-energy learners, with short, actionable video lessons you can complete at your own pace.

References

1. Wu H, Aguilar EG, Tian L, et al. Inflammatory and metabolic signatures in post-acute sequelae of SARS-CoV-2 infection (PASC). Cell Metab. 2023;35(1):28-46.e5. doi:10.1016/j.cmet.2022.12.001

2. Cordero MD, Cano-García FJ, Alcocer-Gómez E, et al. Clinical symptoms in fibromyalgia are better associated to lipid peroxidation levels in blood mononuclear cells rather than in plasma. PLoS One. 2010;5(4):e10228. doi:10.1371/journal.pone.0010228

3. Brown L, Rosner B, Willett WW, Sacks FM. Cholesterol-lowering effects of dietary fiber: a meta-analysis. Am J Clin Nutr. 1999;69(1):30-42. doi:10.1093/ajcn/69.1.30

4. Giloteaux L, Goodrich JK, Walters WA, et al. Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome. Microbiome. 2016;4(1):30. doi:10.1186/s40168-016-0171-4

5. Weickert MO, Pfeiffer AF. Metabolic effects of dietary fiber consumption and prevention of diabetes. J Nutr. 2008;138(3):439-442. doi:10.1093/jn/138.3.439

6. Corella D, Ordovás JM. Aging and cardiovascular diseases: the role of gene-diet interactions. Ageing Res Rev. 2014;18:53-73. doi:10.1016/j.arr.2014.06.006

7. Canfora EE, Jocken JW, Blaak EE. Short-chain fatty acids in control of body weight and insulin sensitivity. Nat Rev Endocrinol. 2015;11(10):577-591. doi:10.1038/nrendo.2015.128

8. Nagy-Szakal D, Barupal DK, Lee B, et al. Insights into myalgic encephalomyelitis/chronic fatigue syndrome phenotypes through comprehensive metabolomics. Sci Rep. 2021;11(1):14329. doi:10.1038/s41598-021-93859-7