The Carnivore Diet Conundrum

Weighing the Risks of Hyperlipidaemia and Metabolic Dysregulation

Over the past several years, the carnivore diet—consisting almost exclusively of animal-sourced foods such as meat, fish, and dairy—has attracted attention for its purported benefits in weight management and glycaemic control. While the diet’s high protein and ultra-low carbohydrate content may hold appeal, emerging evidence and clinical case reports raise substantial concerns. These concerns include extreme elevations in lipid parameters (sometimes mimicking homozygous familial hypercholesterolemia), a potential acceleration of metabolic syndrome risk, and the possibility of diet-induced nutrient deficiencies. At this early stage in the research space, frontline clinicians must remain vigilant. It is imperative to understand these risks, provide evidence-based guidance, and monitor patients closely if they choose or inquire about strictly carnivorous eating patterns.

Dyslipidaemia and Dietary Habits

A recent review of 686 patients (mean age ~62.6±8 years) with dyslipidaemia and/or type 2 diabetes mellitus underscores the impact of dietary habits on long-term cardiometabolic outcomes. Notably, while more than half (56.8%) of these patients achieved adequate glycaemic control (HbA1c <7%), the majority were overweight or obese (BMI 31.8±7.25). In examining their eating patterns, the consumption of a balanced breakfast (p=0.001) and having two main meals (p=0.008) were positively correlated with better lipid and glycaemic control. Meanwhile, frequent intake of junk food (p=0.009), soft drinks (p=0.056), and sweets (p<0.001) negatively impacted metabolic and lipid parameters. Notably, those following a Mediterranean-like diet were found to have a lower prevalence of metabolic syndrome.

Hyperlipidaemia in Carnivore Diet Adherents

One of the most striking clinical warnings comes from two young, otherwise healthy male patients who adopted a strict carnivore diet for a year. They presented with LDL-cholesterol levels exceeding 15 mmol/L (≈580 mg/dL)—a threshold typically suggestive of homozygous familial hypercholesterolemia. However, genetic testing revealed no familial hypercholesterolemia mutations, pointing instead to the dietary pattern itself as a potent driver of their dyslipidaemia.

Detailed fractionation of lipoprotein profiles showed disproportionate elevations of VLDL and IDL, indicating severe hyperlipoproteinemia likely stemming from high levels of dietary saturated fat and cholesterol. Although liver fat remained low in these individuals (based on imaging), both displayed early indicators of atherosclerosis (increased carotid intima-media thickness). As GPs often manage lipid testing and initial patient counselling, it is essential to consider the carnivore diet as a potential cause of alarmingly high LDL-C in patients otherwise lacking a clear genetic aetiology.

Metabolic Syndrome and NAFLD Considerations

Given the tight link between dyslipidaemia, DM2, and metabolic syndrome, practitioners should also be aware of non-alcoholic fatty liver disease (NAFLD) risk in patients consuming very high proportions of saturated fat. In a recent retrospective study from a lipid clinic, 43% of patients had metabolic syndrome, and nearly a quarter showed elevated Fibrosis-4 (FIB-4) scores suggestive of advanced fibrosis risk.

A carnivore diet eliminates sugary beverages and refined carbohydrates—known contributors to NAFLD—but simultaneously overloads patients with saturated fats. This shift could still disrupt lipid metabolism and, over time, foster other metabolic derangements. From a primary care perspective, ordering liver function tests (including AST and ALT) and calculating FIB-4 in high-risk or symptomatic patients may detect subclinical NAFLD, guiding early interventions.

Stress and Lifestyle Factors

Diet is only one facet of cardiometabolic risk. Research also highlights how chronic stress can adversely affect cardiovascular disease (CVD) outcomes. A cross-sectional study of 145 middle-aged women found higher hair cortisol and cortisone correlated with increased waist circumference, blood pressure, and higher SCORE2 risk index for CVD. While carnivore dieters may experience initial weight loss or glucose control, psychological stress from stringent dietary restrictions or social isolation may further complicate a patient’s cardiometabolic profile over time. Addressing these stressors, alongside dietary modifications, is crucial in primary care management.

Proceed with Caution

Primary care providers are often the first to encounter patients exploring restrictive eating patterns, including the carnivore diet. Given the potential for significant rises in LDL cholesterol levels, micronutrient deficiencies, and other metabolic complications, general practitioners should remain vigilant. Before recommending or endorsing any diet, it is prudent to obtain thorough lipid panels (ideally including LDL particle number or apoB) when extreme hyperlipidaemia is apparent. 

It is also essential to screen for micronutrient insufficiencies, particularly because eliminating fruits, vegetables, and whole grains can deprive patients of important vitamins and fibre. Evaluating liver function through AST and ALT tests—and calculating FIB-4 if there are signs of metabolic syndrome—helps detect subclinical fatty liver disease before it progresses. Where persistently high LDL cholesterol is observed, consider imaging studies such as carotid ultrasound or coronary artery calcium scoring to assess for early signs of atherosclerosis. Lifestyle and psychological support can be invaluable, especially if restrictive eating patterns trigger stress or social isolation. 

Finally, ensure shared decision-making by highlighting the limited long-term safety data on the carnivore diet and presenting evidence-based alternatives—such as a Mediterranean or moderate low-carbohydrate approach—to protect patients’ cardiovascular and metabolic health.

A Call for Vigilance in Primary Care

Referring patients to a registered dietitian can be a key step in guiding them through any significant dietary change, including highly restrictive patterns such as the carnivore diet. Dietitians are trained to assess individual nutritional needs, identify potential micronutrient imbalances, and tailor eating plans to address specific health goals and medical conditions. By incorporating a dietitian into the care team, primary care providers can ensure that patients receive ongoing support, education, and practical strategies for meal planning, recipe modification, and balanced supplementation if necessary. This collaborative approach helps patients remain well-informed about the risks and benefits of their chosen eating pattern and reduces the likelihood of unintended health consequences.

Although a carnivore diet may lead to short-term weight loss or improved glycaemic parameters in some individuals, the mounting evidence of potentially severe hyperlipidaemia, early atherosclerosis, and dietary nutrient gaps should raise red flags. For GPs, maintaining a high index of suspicion and carefully monitoring cholesterol, liver function, and overall cardiometabolic status is critical.

Tromp, T.R., Houttu, V.A.T., Levels, J.H.M., Nederveen, A.J., Hovingh, G.K. and Stroes, E.S. (2022) ‘Carnivore diet – a rare cause for dyslipidemia mimicking homozygous FH’, Atherosclerosis, 355, p. e241. Available at: https://www.atherosclerosis-journal.com/article/S0021-9150(22)00975-3/fulltext