A German study found people adopting a carnivore diet experienced an average 100-point increase in LDL cholesterol, raising concerns about long-term health effects. The research, published in April 2025, monitored 24 individuals before and after switching to a diet limited to animal products. Their median LDL levels rose from 157 mg/dL to 256 mg/dL, while total cholesterol climbed from 224 mg/dL to 305 mg/dL. The researchers described the increase as significant, though they acknowledged limitations: participants were recruited at a carnivore diet convention, and no control group was included.
These findings align with earlier observations. A 2021 survey of 2,029 self-identified carnivore dieters found their average LDL stood at 172 mg/dL—well above the 100 mg/dL level often recommended for heart disease prevention. While some participants reported benefits like weight loss or improved energy, the study lacked data on long-term health outcomes such as heart attacks or strokes.
A 2026 review in Nutrients examined nine studies from 2021 to 2025, most of which were case reports or small surveys. The reviewers concluded that any reported improvements might reflect subjective perceptions, placebo effects, or ketosis rather than lasting health gains. They stated that current evidence does not support long-term adherence to the carnivore diet.
Extreme cholesterol spikes trigger rare skin warnings
A striking case illustrates potential dangers. A man in his 40s developed yellowish nodules on his palms and elbows after eight months on the diet. His total cholesterol had reached over 1,000 mg/dL, five times the healthy range, though he felt better than ever. Doctors diagnosed xanthomas, a rare skin condition linked to severe cholesterol elevation. Unaware of his high levels, he was advised to switch to a more balanced diet and begin medication.
Xanthomas are painless but indicate serious metabolic issues. Most people with high LDL show no visible symptoms, making regular blood tests key. The German study’s lead author, Rainer J. Klement, disclosed a conflict of interest: he follows an animal-based diet and has received refunds from carnivore diet product companies. The study’s reliance on self-reported data from a convention crowd means its results should be considered preliminary rather than definitive.
The debate centers on two key issues: individual differences and long-term evidence. Some participants in the German study saw improvements in triglycerides or blood sugar, while others fit the “lean mass hyper-responder” profile; those whose LDL spikes sharply while HDL remains high. Whether this pattern increases heart risk remains unclear. A planned UK trial in 2026 may provide clearer answers by comparing carnivore and Mediterranean diets over three weeks, focusing on how LDL particles clump, a key factor in atherosclerosis.
Uncertain trade-offs leave long-term risks unanswered
Current data suggests a trade-off: short-term benefits for some, but a consistent rise in LDL, a known risk factor for cardiovascular disease. The question remains whether the diet’s potential advantages justify the unknowns for long-term adopters.
The case of the man with xanthomas, published in JAMA Cardiology, serves as a warning. His yellowish nodules on palms, soles, and elbows appeared after eight months on the diet, alongside a total cholesterol reading above 1,000 mg/dL. His daily intake included 6 to 9 pounds of cheese, butter, and extra fat, though the study did not specify consistency. Despite his extreme cholesterol levels, he reported feeling better than ever, showing how high LDL often goes unnoticed without testing. Doctors diagnosed his condition as xanthomas, a visible sign of severe metabolic disruption.
To address remaining uncertainties, Liverpool John Moores University has registered a small randomized trial (NCT07462871) set to begin in June 2026. The study will compare a carnivore-style diet to a Mediterranean-style diet in about 30 adults with raised LDL over three weeks. Researchers will examine how LDL particles clump, a key factor in atherosclerosis. Though limited in scope, the trial may offer preliminary insights into whether the carnivore diet alters LDL structure in ways that could heighten cardiovascular risk.
