The carnivore diet, characterized by the exclusive consumption of animal products, has garnered attention for its potential benefits, including weight loss, mental clarity, and inflammation reduction. However, concerns have been raised regarding its impact on kidney health, particularly the risk of kidney stones. This article aims to explore the relationship between the carnivore diet and kidney stone formation, providing a balanced perspective based on available evidence.
Understanding the Carnivore Diet
The carnivore diet is a restrictive dietary approach that involves consuming only animal-based foods, such as meat, poultry, eggs, seafood, fish, and some dairy products. It excludes all plant-based foods, including fruits, vegetables, grains, legumes, seeds, and nuts. As the most ketogenic diet, the carnivore diet restricts calories from glucose and other forms of sugar, the body burns fat that creates ketones as an energy source.While some keto diets can emphasize the intake of healthier mono- and polyunsaturated fats, that's not the case with carnivore diets.
Kidney Function and High-Protein Diets
The kidneys are vital organs responsible for maintaining the body's internal environment by filtering waste products from the blood, regulating fluid balance, and producing hormones. A primary concern regarding the carnivore diet is the increased protein intake and its potential impact on kidney function.
Healthy kidneys are generally capable of efficiently filtering out the byproducts of protein metabolism, such as urea and ammonia. Studies have shown that high-protein diets do not pose a significant risk to individuals with normal kidney function. However, individuals with compromised kidney function may experience difficulties processing the increased protein load, potentially exacerbating existing kidney problems.
The Link Between Carnivore Diet and Kidney Stones
The carnivore diet's potential to increase the risk of kidney stones is a valid concern. Every year, more than three million people seek treatment for symptoms related to kidney stones. Although there is a connection to genetic predisposition, the causes of kidney stones are often related to diet and lifestyle. There is no one specific cause of kidney stones. Kidney stones form when certain minerals in urine become highly concentrated, leading to the formation of crystals that can develop into stones. Several factors associated with the carnivore diet may contribute to this process:
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- Increased Uric Acid Levels: High consumption of animal protein, particularly red meat, can elevate uric acid levels in the urine, increasing the risk of uric acid stones.
- Elevated Calcium Levels: Urine studies demonstrate an increase in urine calcium, likely due to increased sodium intake or increased acid load from high purine consumption.
- Reduced Citrate Levels: Citrate is a protective factor that inhibits the formation of calcium stones. High animal protein intake can decrease urinary citrate levels, promoting stone formation.
- Increased Oxalate Levels: Some studies suggest that high animal protein diets may increase urinary oxalate excretion, potentially due to lower dairy intake, which reduces calcium to bind oxalate in the intestine.
- High Sodium Intake: Processed meats, often consumed on the carnivore diet, can be high in sodium. Sodium increases the excretion of calcium, which is a risk factor for kidney stones.
Case Study: Impact of Carnivore Diet on Kidney Stone Development
A 2025 study published in The American Journal of Clinical Nutrition examined the impact of the carnivore diet on kidney stone risk in a 61-year-old man with a history of kidney stones, gout, hypertension, coronary artery disease, and diabetes (Wilson, H. E., & Moe, S. M. (2025). You are what you eat-Should it be all meat?: Impact of the carnivore diet on the risk of kidney stone development. The American Journal of Clinical Nutrition, 121(2), 197-202.). The patient initially developed kidney stones at age 45 and underwent multiple lithotripsy procedures. Analysis of the stones revealed a composition of 10% calcium phosphate and 90% calcium oxalate.
The patient subsequently adopted a 90% meat-based diet after watching a YouTube video advocating for the carnivore diet as a gout treatment. Urine studies revealed elevated calcium, sodium, oxalate, and uric acid levels, as well as increased supersaturation levels for calcium phosphate and oxalate. Despite adequate fluid intake, the patient continued to pass stones, which now comprised calcium phosphate, calcium oxalate, and 10% uric acid. During this period, he also developed gout and high blood pressure.
After discontinuing the carnivore diet at age 68, the patient stopped forming stones and experienced no further urological symptoms. This case study highlights the potential risks of the carnivore diet for individuals with a history of kidney stones or other predisposing factors.
Mitigating Kidney Stone Risk on the Carnivore Diet
While the carnivore diet may increase the risk of kidney stones, several strategies can help mitigate this risk:
- Hydration: Adequate water intake is crucial for diluting urine and reducing the concentration of minerals that can form stones. Aim for at least 8-10 glasses of water per day. Extra water dilutes the substances in urine that lead to stones.
- Limit Sodium Intake: Avoid processed meats and other high-sodium foods. To prevent kidney stones, patients should lower sodium intake by avoiding processed soups and meats and substituting salt with herbs.
- Balance Calcium and Potassium: Ensure adequate intake of potassium, which can help regulate calcium levels in the urine. Organ meats and bone broth are good sources of potassium. This is why you need to carefully consider the balance between calcium and potassium in your diet. Organ meats are rich in potassium, as is bone broth, so make these a part of your meal planning.
- Include Citrate-Rich Foods: Although plant-based foods are excluded on the carnivore diet, consider supplementing with potassium citrate to increase urinary citrate levels. Non-dairy animal protein, particularly red meats, should be reduced, while fruits and vegetables such as citrus fruits, bell peppers, broccoli, and bananas should be increased.
- Monitor Kidney Function: Regular monitoring of kidney function is essential, especially for individuals with a family history of kidney problems or underlying health conditions. The only way to know the carnivore diet effect on kidneys with absolute certainty is to regularly monitor it. This is even more important if you have a family history of kidney problems or any underlying health conditions.
General Disadvantages of Keto Diets
The carnivore diet is a type of "keto," or ketogenic, diet. While some keto diets can emphasize the intake of healthier mono- and polyunsaturated fats, that's not the case with carnivore diets. The disadvantage of all keto diets is they tend to raise LDL cholesterol levels in both the short and long term. Other longer-term concerns about keto diets, especially the carnivore diet, include the increased risk of kidney stones, gout, and osteoporosis.
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Conflicting Interests
It is important to acknowledge potential conflicts of interest when evaluating information about the carnivore diet and its effects on health. Some healthcare professionals may have financial relationships with companies that produce or promote certain foods or supplements. For example, Christopher Duggan, MD, MPH (Boston Children’s Hospital), has received grant/research support from Takeda. Sharon Moe, MD (Indiana University School of Medicine) is a scientific advisor for Alebund, Arydyelx, Amgen, and Inozyme and has stock in Eli Lilly. These relationships should be disclosed to ensure transparency and allow individuals to form their own judgments about the information presented.
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