What would happen if a human only ate meat?

January 2, 2026 •

4 min read

Historically, some populations like the Inuit have survived on diets consisting almost entirely of meat, fat, and organs, but the modern concept of eating only meat is linked to a cascade of potential health problems. This raises a critical question for many: what would happen if a human only ate meat?

Quick Summary

An exclusive meat diet can cause severe nutrient deficiencies, digestive issues due to a lack of fiber, increased risk of heart disease, and significant strain on the kidneys.

Key Points

Nutrient Deficiency: An all-meat diet lacks essential vitamins (like Vitamin C), minerals (like magnesium and potassium), fiber, and beneficial plant compounds (phytonutrients), potentially leading to serious health issues.
Cardiovascular Risk: High intake of saturated fat and cholesterol from red and processed meats can elevate 'bad' LDL cholesterol, increasing the risk of heart disease.
Kidney and Liver Strain: Excess protein consumption places a heavy burden on the kidneys and liver, which must work harder to process waste, and may increase the risk of kidney stones.
Digestive Problems: Without dietary fiber, a carnivore diet can cause severe constipation and disrupt the balance of the gut microbiome, which is vital for digestive and immune health.
Protein Poisoning: Consuming too much lean protein without enough fat can cause 'rabbit starvation', a toxic condition with symptoms like nausea and diarrhea.
Balanced Approach is Preferred: Health and nutrition experts do not recommend a long-term all-meat diet, instead advocating for a varied, balanced diet for optimal and sustainable health.

The idea of a meat-only or carnivore diet has gained traction in recent years, often promoted through anecdotal claims of weight loss and reduced inflammation. However, a closer look at the nutritional science reveals a far more complex and risky picture for long-term health. Restricting one's diet to a single food group is fundamentally at odds with the need for a diverse array of nutrients found in a balanced omnivorous diet.

The Problem of Nutritional Deficiencies

One of the most significant drawbacks of an exclusive meat diet is the elimination of crucial nutrients found predominantly in plant-based foods. While meat is rich in protein, B vitamins (including B12), iron, and zinc, it is devoid of other vital compounds. A strict carnivore diet can easily lead to deficiencies in:

Fiber: Found only in plants, fiber is essential for healthy digestion and bowel regularity. Its absence can cause severe constipation and negatively impact the gut microbiome.
Vitamin C: Without citrus fruits, berries, and vegetables, vitamin C intake plummets. While some raw organ meat contains trace amounts, it is not enough to prevent scurvy in the long run. Scurvy is a serious condition causing fatigue, inflammation, and anemia.
Other vitamins and minerals: Important micronutrients like potassium, magnesium, folate, and Vitamin K are primarily sourced from plant foods. Deficiencies in these can lead to a host of issues, from muscle cramps and fatigue to weakened bones and impaired immunity.
Phytonutrients and antioxidants: Plant compounds known as phytonutrients and antioxidants play a vital role in fighting inflammation and preventing chronic diseases. An all-meat diet contains none of these beneficial compounds.

Cardiovascular and Organ Health Risks

A diet high in saturated fats and cholesterol, common with heavy consumption of red meat, can have a detrimental effect on cardiovascular health. This can lead to elevated levels of LDL (the 'bad' cholesterol), which increases the risk of heart disease. Furthermore, the lack of fiber removes one of the body's natural tools for regulating cholesterol levels. The high sodium content found in processed meats also raises concerns about high blood pressure.

High protein intake places a significant burden on the kidneys and liver. These organs must work overtime to process and excrete the increased nitrogen waste from protein metabolism. This long-term stress can damage the kidneys and may contribute to the formation of kidney stones, especially in susceptible individuals.

The Perils of Protein Poisoning

Focusing solely on lean cuts of meat can lead to a dangerous condition known as 'protein poisoning' or 'rabbit starvation'. This occurs when the body's ability to metabolize protein is overwhelmed, causing toxicity symptoms such as nausea, headaches, and diarrhea. Historical accounts of arctic explorers who subsisted on extremely lean rabbit meat documented this condition. To avoid this, those on meat-heavy diets must consume enough fat, typically from organ meats or fatty cuts, but this increases other health risks.

Impact on the Gut Microbiome

Dietary fiber is the primary fuel for the beneficial bacteria in your gut. By completely eliminating plant-based foods, a carnivore diet starves these microbes, leading to a significant reduction in microbial diversity and health. This disruption can cause digestive issues and may also have systemic effects, given the gut microbiome's crucial role in immunity and overall well-being.

How a Carnivore Diet Compares to a Balanced Omnivorous Diet


Feature	Carnivore Diet (Meat Only)	Balanced Omnivorous Diet
Key Nutrient Profile	High in protein, fat, B12, iron, zinc	Wide array of protein, fat, carbohydrates, fiber, vitamins, minerals, and phytonutrients
Fiber Content	Zero	High (from fruits, vegetables, grains)
Saturated Fat & Cholesterol	High, especially with red/processed meat	Moderate, with an emphasis on healthy unsaturated fats
Phytonutrients/Antioxidants	Absent	Rich source
Kidney/Liver Strain	High (due to excess protein)	Moderate
Digestive Health	Constipation, altered gut microbiome	Regular bowel movements, healthy gut flora
Cardiovascular Risk	Increased	Balanced risk factors

Conclusion: An Unnecessary and Risky Approach

While some short-term, anecdotal reports tout the benefits of eliminating processed foods and carbohydrates, the long-term consequences of a strictly carnivorous diet are concerning and not well-researched. Health experts and dietitians widely advise against such a restrictive eating pattern due to the high risks of nutrient deficiencies, increased cardiovascular issues, digestive problems, and potential organ stress. The notion that humans are solely carnivores ignores our evolutionary history and physiological needs for a diverse range of nutrients found in both animal and plant sources. For optimal health and sustained wellness, focusing on a varied and balanced diet remains the evidence-based recommendation. You can learn more about the specific risks discussed here in a detailed report from National Geographic.

Frequently Asked Questions

Yes, it is possible to get scurvy on a carnivore diet if the diet does not include organ meats or raw meat, as muscle meat contains negligible amounts of Vitamin C. Scurvy is a severe condition resulting from a lack of this essential vitamin.

Protein poisoning, also known as 'rabbit starvation', is a form of malnutrition that results from consuming too much lean protein and not enough fat. Symptoms include nausea, headaches, fatigue, and diarrhea.

No. Healthcare professionals and dietitians generally advise against the carnivore diet due to the high risk of nutrient deficiencies and long-term health complications, particularly for individuals with pre-existing conditions like heart or kidney disease.

Any perceived initial benefits, such as weight loss or reduced bloating, are often anecdotal and may be due to the elimination of processed foods and high-carb items rather than the exclusive focus on meat. These short-term effects do not negate the significant long-term risks.

An all-meat diet, especially one high in red and processed meats, can lead to high saturated fat and cholesterol intake. This can raise 'bad' LDL cholesterol levels and increase the risk of cardiovascular disease.

Yes, a very high protein intake puts added stress on the kidneys and liver, as they must work harder to process the metabolic waste. This can lead to complications and an increased risk of kidney stones.

The complete absence of fiber from a carnivore diet can cause severe constipation and negatively impact the gut microbiome. Dietary fiber is crucial for feeding beneficial gut bacteria, which are important for overall digestive and immune health.

Historical populations like the Inuit survived on meat-heavy diets by consuming a much wider variety of animal products, including nutrient-dense organs, fat, and sometimes raw meat, which provided nutrients absent in modern muscle-meat-focused carnivore diets.