Carnivore Diet Studies: What the Science Actually Says

Last updated: May 2026

Carnivore Diet Studies: What the Science Actually Says

The carnivore diet has millions of followers and thousands of social media posts. It has a much smaller body of peer-reviewed research. Here’s what the scientific literature actually contains — the number of studies, their designs, their findings, and their limitations.

How Much Research Exists?

A 2026 scoping review published in Nutrients (Lietz, Dapprich, and Fischer) conducted a systematic search of PubMed, LIVIVO, Web of Science, and the Cochrane Library for all human studies on the carnivore diet published between 1970 and 2025. The result: nine human studies met the inclusion criteria.

All nine were published between 2021 and 2025. Five were case studies or case series. Two were social media surveys. One was an exploratory observational study. One was a comparative modeling study analyzing nutrient composition. None were randomized controlled trials.

The authors rated the overall quality of evidence as NHMRC Levels III–IV (the lowest quality categories in evidence hierarchies). Their conclusion: “it is not currently possible to reliably assess the long-term safety of the CD.”

The Nine Studies: Key Findings

1. Lennerz et al. (2021) — Social Media Survey, USA

n = 2,029 adults; median diet duration 14 months

The largest dataset on the carnivore diet. Participants self-reported:

• Improvements in overall health, energy, sleep, mental health, and body weight
• Reduced diabetes medication use
• Improved CRP (inflammatory marker): 1.0 → 0.7 mg/dL (p<0.01)
• Improved GGT (liver enzyme): 18 → 15 U/L (p<0.01)
• Improved triglyceride/HDL ratio
• Elevated LDL and total cholesterol — reported as a negative outcome by 27% of participants

Limitation: All findings are self-reported, no clinical verification, recruited from carnivore social media communities (strong selection bias), no information on pre-diet food intake.

2. Goedeke et al. (2024) — Nutrient Composition Analysis, New Zealand

Theoretical meal plans; no human participants

Developed four carnivore diet meal plans (two female, two male — with and without dairy) and analyzed against Australian/New Zealand nutrient reference values. Key findings:

• Above recommendations: Vitamin B12 (2,917% of RDI from liver), riboflavin, niacin, zinc, selenium, phosphorus, Vitamin A
• Below recommendations: Thiamin, Vitamin C, calcium, magnesium, potassium, fiber (<1g/day vs 25–30g recommended)
• Adding dairy improved calcium but still fell short of RDI
• Including liver covered folate and iron in female plans

3. Klement & Matzat (2025) — Exploratory Study, Germany

n = 24; median diet duration 17 months

Measured blood parameters before and during the carnivore diet:

• Metabolically unhealthy participants showed improvements in HbA1c and triglycerides
• Metabolically healthy participants experienced worsening of HbA1c and triglycerides
• TC rose from median 224 → 305 mg/dL (p<0.0001)
• LDL rose from 157 → 256 mg/dL (p=0.00024)

This study is notable for showing that the diet may behave differently depending on metabolic starting point.

4. Norwitz & Soto-Mota (2024) — Case Series, Inflammatory Bowel Disease

n = 7 IBD patients; median diet duration 1 year

All 7 patients with Crohn’s disease or ulcerative colitis achieved clinical remission on a carnivore-ketogenic diet. Fecal calprotectin (IBD severity marker) dropped dramatically. Five reduced or discontinued medications. This is the strongest clinical evidence for any specific condition benefit from the carnivore diet. LDL and total cholesterol increased in this cohort as well.

5. Yar et al. (2022) — Case Study, Candida and Hidradenitis

n = 1 female patient; 43-day intervention + 47-month follow-up

Patient with recurrent Candida vulvovaginitis and hidradenitis suppurativa achieved complete symptom remission within 43 days on a zero-carb, all-meat ketogenic diet. Sustained improvement at 47-month follow-up. Proposed mechanism: ketosis shifts energy availability toward host cells and exerts anti-inflammatory effects.

6. Wilson & Moe (2025) — Case Report, Kidney Stones

n = 1 male patient (67 years)

One documented case of health deterioration: 24-hour urine profile shifted unfavorably, calcium and oxalate excretion increased, uric acid supersaturation more than doubled, and the patient developed recurrent gout flares requiring increased allopurinol dosage. After discontinuing the carnivore diet, the patient remained free of kidney stones for one year. This is the clearest evidence of individual harm.

7. Karačić et al. (2024) — Gut Microbiome Study

n = 1 carnivore + omnivore comparison cohort (n=151)

Compared gut microbiome of one long-term carnivore (4+ years) to omnivore controls. No significant differences in alpha or beta diversity were found — challenging the common assumption that the carnivore diet destroys microbiome diversity.

8. Phelan et al. (2023) — Dietary Quality Comparison

Compared seven popular diet patterns using the Healthy Eating Index. The carnivore diet scored lowest (30/100). Compared to RDAs, showed reduced calcium, Vitamin D, fiber, and potassium.

9. Protogerou et al. (2021) — Social Media Survey (Zero-Carb Practitioners)

n = 170; 25 countries

Self-reported improvements in health, satiety, sleep. Key social finding: zero-carb practitioners frequently reported social conflict with family, friends, and healthcare professionals outside the community.

What We Can and Cannot Conclude

What the evidence supports:

• Short-term weight loss and appetite suppression are likely for most people
• Blood sugar and insulin improvements are consistent and likely real
• Reduced inflammatory markers (CRP, GGT) have been documented, though causation is not established
• Clinical remission in IBD is documented in a small case series and is the most compelling specific-condition finding
• Nutrient deficiencies in thiamin, Vitamin C, calcium, magnesium, and fiber are likely without supplementation or liver/seafood inclusion
• LDL and total cholesterol elevation is consistent across multiple studies

What the evidence does not support:

• Long-term safety cannot be assessed — no study exceeds about 2 years
• Long-term cardiovascular outcomes are completely unknown
• Most benefit claims come from self-reported survey data from highly self-selected groups
• No randomized controlled trials exist

Why So Little Research?

The carnivore diet did not appear in a scientific article’s title until 2020. Funding for nutrition research is challenging in general, and studies on extreme dietary patterns without existing clinical evidence to justify them are particularly difficult to fund. Researchers must weigh whether the preliminary evidence justifies the investment when significant questions remain about safety.

Frequently Asked Questions

Has the carnivore diet been proven safe?

No — and the absence of proof of harm is not the same as proof of safety. The 2026 scoping review explicitly states that long-term safety cannot currently be assessed. Short-term use (weeks to months) appears to be tolerable for most healthy adults, but long-term outcomes, particularly for cardiovascular health, are unknown.

Are there any randomized controlled trials on carnivore?

No. As of the 2026 scoping review, all nine identified studies are observational (surveys, case studies, or modeling analyses) — none involve random assignment or control groups. This is the fundamental limitation of the entire evidence base.