The carnivore diet, a highly restrictive dietary approach consisting exclusively of meat, fish, and other animal products, has gained traction in recent years. Proponents claim it can aid weight loss, improve mood issues, and regulate blood sugar, among other health benefits. However, this diet eliminates all other foods, including fruits, vegetables, legumes, grains, nuts, and seeds, raising concerns about its long-term health implications and potential nutrient deficiencies. This article delves into the sources of calcium on a carnivore diet, examining its potential benefits and drawbacks, and addressing concerns about nutrient adequacy.
Understanding the Carnivore Diet
The carnivore diet stems from the controversial belief that human ancestral populations primarily consumed meat and fish and that high-carb diets are responsible for today’s high rates of chronic diseases. Unlike other low-carb diets like the keto and paleo diets, which limit but don’t exclude carb intake, the carnivore diet aims for zero carbs.
What the Carnivore Diet Includes
The carnivore diet includes only animal products, such as:
- Meat: Beef, chicken, turkey, lamb, pork, etc.
- Organ meats: Liver, kidney, sweetbread, tripe, heart, brain
- Fish: Salmon, mackerel, sardines, crab, lobster, tilapia, herring, etc.
- Other animal products: Eggs, lard, bone marrow, bone broth, etc.
- Low-lactose dairy (in small amounts): Heavy cream, hard cheese, butter, etc.
- Water
Some proponents of the diet allow salt, pepper, and seasonings with no carbs. Some people also choose to eat yogurt, milk, and soft cheese, but these foods are typically not included due to their carb contents.
What the Carnivore Diet Excludes
All foods that do not come from animals are excluded from the carnivore diet, including:
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- Vegetables: Broccoli, cauliflower, potatoes, green beans, peppers, etc.
- Fruits: Apples, berries, bananas, kiwi, oranges, etc.
- High-lactose dairy: Milk, yogurt, soft cheese, etc.
- Legumes: Beans, lentils, etc.
- Nuts and seeds: Almonds, pumpkin seeds, sunflower seeds, pistachios, etc.
- Grains: Rice, wheat, bread, quinoa, pasta, etc.
- Alcohol: Beer, wine, liquor, etc.
- Sugars: Table sugar, maple syrup, brown sugar, etc.
- Beverages other than water: Soda, coffee, tea, fruit juice, etc.
Calcium on the Carnivore Diet: Sources and Considerations
Calcium is an essential mineral crucial for bone health, muscle function, nerve transmission, and blood clotting. Dairy products are often considered the primary source of calcium in a typical diet. However, the carnivore diet restricts or eliminates many traditional calcium sources, raising concerns about potential deficiencies.
Calcium Content in Carnivore-Friendly Foods
- Meat: While meat does contain some calcium, the amount is relatively small. A pound of steak, for instance, contains only about 25 mg of calcium, a minuscule amount compared to the recommended daily intake.
- Egg yolks: Egg yolks contain a small amount of calcium, with one egg yolk providing approximately 10-15 mg of calcium.
- Dairy products: Some individuals on a carnivore diet include small amounts of low-lactose dairy products like hard cheese, heavy cream, and butter. Cheddar cheese, for example, is relatively high in calcium compared to butter.
- Bone broth: Bone broth, made by simmering animal bones in water, can be a source of calcium and other minerals. However, the calcium content can vary depending on the bones used and the preparation method.
- Sardines: Sardines, especially when consumed with their bones, can provide a significant amount of calcium.
- Bone Marrow: Bone marrow can provide a source of calcium.
Addressing Calcium Concerns on a Carnivore Diet
Given the limited calcium sources on a strict carnivore diet, it is essential to address potential deficiencies:
- Monitoring calcium levels: It is advisable to monitor calcium levels through blood tests, including parathyroid hormone (PTH) and N-Telopeptide (NTx) levels. Elevated PTH levels may indicate that the body is pulling calcium from the bones to maintain adequate blood calcium levels.
- Including bone-containing foods: Consuming foods like sardines with bones can help increase calcium intake.
- Considering dairy: If tolerated, including small amounts of low-lactose dairy products like hard cheese can contribute to calcium intake.
- Optimizing vitamin K2 intake: Vitamin K2 plays a crucial role in calcium metabolism, helping to direct calcium to the bones and teeth rather than accumulating in soft tissues. The carnivore diet, particularly when including grass-fed animal products, can provide adequate amounts of vitamin K2. Muscle meat, liver, and egg yolks are good sources of K2.
- Supplementation: Calcium supplementation may be considered if dietary intake is insufficient. However, it's essential to consult with a healthcare professional before supplementing, as excessive calcium intake can have adverse effects.
The Role of Vitamin K2
Vitamin K2 is abundant in a carnivore diet, especially when consuming grass-fed animals. Muscle meat has a decent amount of K2, liver has K2, and egg yolks have K2. The fat-soluble vitamins are needed to move calcium around the body in the right way.
Potential Benefits and Downsides of the Carnivore Diet
While the carnivore diet may offer some potential benefits, it also has several drawbacks that need to be considered.
Potential Benefits
- Weight loss: The high protein and fat content of the carnivore diet can promote satiety, leading to reduced calorie intake and subsequent weight loss.
- Blood sugar regulation: Eliminating refined carbs and sugary foods can help regulate blood sugar levels, which may be beneficial for individuals with diabetes.
- Reduced inflammation: Some proponents claim that eliminating plant-based foods can reduce inflammation and improve symptoms of autoimmune conditions. However, more research is needed to support these claims.
Potential Downsides
- Nutrient deficiencies: The carnivore diet eliminates many nutrient-rich foods, increasing the risk of deficiencies in vitamins, minerals, and fiber. A study assessed the nutrient adequacy of four versions of the carnivore diet against national nutrient reference values (NRVs) from the Australian National Health and Medical Research Council (NHMRC) and New Zealand Ministry of Health. The carnivore diet met several NRV thresholds for nutrients such as riboflavin, niacin, phosphorus, zinc, Vitamin B6, Vitamin B12, selenium, and Vitamin A, and exceeded the sodium threshold. However, it fell short in thiamin, magnesium, calcium, and Vitamin C, and in iron, folate, iodine and potassium in some cases. Fibre intake was significantly below recommended levels.
- High fat and cholesterol intake: The carnivore diet can be high in saturated fat and cholesterol, which may raise LDL (bad) cholesterol levels and increase the risk of heart disease.
- Lack of fiber: The absence of fiber in the carnivore diet can lead to constipation and negatively impact gut health. Fiber is essential for the proper balance of bacteria in the gut.
- Restrictive and difficult to maintain: The highly restrictive nature of the carnivore diet makes it challenging to follow long term and may lead to food cravings and dissatisfaction.
- Not suitable for some populations: The carnivore diet may be problematic for individuals with kidney disease, cholesterol hyper-responders, pregnant or lactating women, children, and those with a history of disordered eating.
Addressing Micronutrient Adequacy on a Carnivore Diet
A study by Goedeke, Murphy, Rush, & Zinn (2025) assessed the nutrient composition of a carnivore diet using a case study model. The findings demonstrated that while most NRV thresholds were achieved, the intake of several nutrients was lower than NRV recommendations. This study emphasized the importance of nutritional guidance in addressing micronutrient gaps, particularly for those excluding key food groups such as dairy or offal.
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Key Micronutrient Considerations
- Thiamin (Vitamin B1): The carnivore diet may be insufficient in thiamin, a vitamin crucial for cellular energy metabolism. However, it has been speculated that in the context of diets characterized by carbohydrate reduction, it may be that the requirement for thiamin is reduced due to a reduction in thiamin-requiring glycolytic metabolism
- Folate: Folate requirements may be sufficiently met by including liver and eggs in the diet.
- Vitamin C: Some theories suggest that the high carnitine content in animal products may have Vitamin C-sparing effects.
- Calcium and Magnesium: Calcium and magnesium intakes may be below the RDI in all the theoretical meal plans.
Sample Carnivore Diet Menu
Here’s a five-day sample menu for the carnivore diet:
Day 1
- Breakfast: eggs, bacon, sardines
- Lunch: turkey burger patty, salmon jerky, beef tips
- Dinner: filet mignon, crab, chicken liver
- Snacks: a small amount of Parmesan cheese, jerky
Day 2
- Breakfast: shrimp, eggs, a small glass of heavy cream
- Lunch: strip steak, tuna fish, beef jerky
- Dinner: lamb chops, scallops, beef liver
- Snacks: a small amount of hard Cheddar cheese, bone broth
Day 3
- Breakfast: eggs, salmon, turkey sausage
- Lunch: sweetbreads, pork chops, mackerel
- Dinner: turkey burger patty, a small amount of Parmesan cheese, bone marrow
- Snacks: hard-boiled eggs, shrimp
Day 4
- Breakfast: trout, shredded chicken, bacon
- Lunch: beef meatballs, small amount Cheddar cheese, salmon jerky
- Dinner: crab cooked in lard, filet mignon
- Snacks: sardines, beef jerky
Day 5
- Breakfast: eggs, chicken and turkey sausage links
- Lunch: lamb roast, chicken liver, pork chop
- Dinner: flank steak, scallops cooked in butter, a small glass of heavy cream
- Snacks: bone broth, turkey jerky
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