The Carnivore Diet: Is Extreme Keto Healthy for Weight Loss?

Ketogenic or “keto” diets are meal plans that are very low in carbohydrates, and very high in fat and protein. The extreme limitation of carbs, including vegetables, fruits and grains, forces the body into a physiological state called ketosis. While in ketosis, the body is forced to burn fat for energy instead of glucose.

The carnivore diet is the most extreme version of keto-eating in that it virtually eliminates all carbohydrates, focusing on meat, fish, poultry, eggs and some dairy products like butter and cheese. For this reason, it is sometimes called the zero-carb diet.

“Although ketogenic diets can be effective for rapid weight loss, eliminating entire food groups, even in the short term, can have negative consequences,” says Susan Campbell, RD, LD, a registered dietitian at University Hospitals. “The carnivore diet, in particular, with its very high fat content, comes with numerous health concerns.”

Risks Associated With the Carnivore Diet

Consuming only animal products can pose a variety of health risks, including:

• Lack of Key Nutrients. By excluding all plant-based foods, the carnivore diet increases the risk of nutritional deficiencies, including vitamins C, E and K, folate and magnesium. Insufficient dietary supplies of these vitamins and minerals can lead to fatigue, weakened immunity and other health issues.
• Increased Risk of Heart Disease. The high levels of saturated fat in animal products can raise LDL (bad) cholesterol and greatly increase the risk of heart disease, heart attack and stroke.
• Digestive Problems. A strict carnivore diet lacks dietary fiber which can lead to constipation or diarrhea, gas, bloating and an increased risk of colon cancer. Low- or no-fiber diets can also disrupt the balance of gut bacteria which some studies suggest can lead to fatigue, skin rashes, difficulty concentrating and even mood changes like anxiety or depression.
• Renal stress. The high protein intake associated with the carnivore diet can put a strain on the kidneys and increase the risk for kidney stones. It can also raise uric acid levels in the body and increase your chances for developing gout.

“In addition, the extreme food restrictions imposed by the carnivore diet make it an unsustainable eating plan for most people,” says Campbell.

Potential Benefits of an Extreme Keto Diet

Because it eliminates common allergens and irritants like gluten, dairy (to some extent) and plant-based compounds such as lectins or oxalates, people with certain health conditions may experience some symptom relief when on the carnivore diet. Conditions include:

• Autoimmune conditions like rheumatoid arthritis, psoriasis and lupus.
• Digestive disorders like Crohn’s disease.
• Skin conditions like acne and eczema.
• Diabetes.
• Mood disorders like anxiety.

Who Should Avoid It?

People with a history of heart disease, kidney issues or nutrient deficiencies should approach the carnivore diet with caution. In addition, pregnant women, children and those with compromised immune systems may also need a more balanced diet to meet their nutritional needs.

“There is limited research around the long-term impact of the carnivore diet and it remains a controversial choice,” says Campbell. “Anyone considering any new diet plan should always consult a healthcare professional before making any dramatic changes. In general, I recommend eating plans like the Mediterranean or the DASH diet that focus on moderation not elimination for longer-term, sustainable success.”

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The clinical dietitians at University Hospitals have the knowledge, advanced training and experience to help patients develop healthy eating plans to optimize overall health and prevent or manage certain health conditions.