Why are there no carbs on a carnivore diet?

November 23, 2025 •

4 min read

While carbohydrates are the body's preferred and primary energy source for most people, the carnivore diet operates on an entirely different principle. This eating plan strictly eliminates all plant-based foods, resulting in a virtually zero-carb intake. Proponents argue this approach triggers a powerful metabolic shift, moving the body into a state of ketosis where it burns fat for fuel instead of glucose.

Quick Summary

The carnivore diet eliminates all plant foods, naturally containing no carbohydrates. This forces the body into ketosis, utilizing fat and ketones for energy instead of glucose from carbs, relying on protein and fat for fuel.

Key Points

Metabolic Shift: The carnivore diet's zero-carb nature forces the body into ketosis, where it burns fat for energy instead of glucose.
Elimination Philosophy: The diet eliminates all plant-based foods, which are the primary sources of carbohydrates, to avoid potential irritants and align with ancestral eating patterns.
Energy from Fat and Protein: With carbs removed, the diet is high in fat and protein, which provide the body with energy and promote feelings of fullness.
Natural Glucose Production: The body can produce the small amount of glucose it needs through a process called gluconeogenesis, utilizing protein and fat.
Ketosis Benefits: Supporters claim the shift to ketosis improves mental clarity, provides more stable energy, and aids in weight loss.
Highly Restrictive: The complete elimination of entire food groups is the core mechanism of the diet, making it the most restrictive form of a ketogenic diet.

The Metabolic Shift to Ketosis

The fundamental reason for the absence of carbohydrates on a carnivore diet is to force a metabolic change known as ketosis. Typically, the body relies on glucose from carbohydrates for energy. When dietary carbs are removed, the body depletes its glycogen stores and seeks an alternative fuel source. This leads to the liver converting fat into molecules called ketones, which the body and brain can then use for energy.

The Body's Adaption to Fat-Burning

This process, often referred to as 'fat adaptation,' can take several weeks and may include a transition period known as the 'keto flu,' with symptoms like headaches and fatigue. Once adapted, many followers report stable energy levels and reduced hunger. The zero-carb structure of the carnivore diet is simply the most extreme way to achieve this ketogenic state, making it a stricter form of a traditional ketogenic diet.

Can the Body Function Without Glucose?

For some, the idea of zero dietary carbohydrates is concerning because glucose is vital for certain bodily functions. However, the body is capable of producing its own glucose through a process called gluconeogenesis. This metabolic pathway uses amino acids from protein and fatty acids from fat to create the small amount of glucose necessary for functions that cannot run on ketones. This proves the body is well-equipped to function without relying on external carbohydrate sources.

The Elimination of Plant-Based Foods

Another core philosophy behind the carnivore diet's zero-carb nature is the complete elimination of plant foods. Proponents believe that certain compounds found in plants can be inflammatory or disruptive to human health. These include lectins, oxalates, and phytates, which some believe can cause digestive issues or autoimmune flare-ups.

The Ancestral Eating Hypothesis

The carnivore diet draws on an ancestral eating hypothesis, suggesting that human ancestors consumed a diet primarily of meat and fat, especially in certain climates. By removing all plant foods, followers aim to strip their diet back to a perceived state of simplicity, believing it can help resolve issues that arose with the advent of agriculture. The zero-carb structure is a direct result of this elimination philosophy, as most significant carb sources are plant-based.

Here are some of the food groups eliminated on a carnivore diet and why:

Fruits and Vegetables: Excluded to eliminate all sources of carbohydrates and potential plant irritants.
Grains and Legumes: Eliminated due to high carbohydrate content and compounds like lectins.
Nuts and Seeds: Excluded because they contain carbohydrates and other compounds believed to cause inflammation.

Carnivore vs. Keto: Carb Intake Comparison

To better understand the zero-carb stance of the carnivore diet, it is helpful to compare it to the related ketogenic diet. While both are low-carb, their approaches differ significantly.


Feature	Carnivore Diet	Keto Diet
Carbohydrate Intake	Virtually 0g (trace amounts in some animal products)	Typically 20–50g net carbs/day
Allowed Foods	Exclusively animal products (meat, fish, eggs, some dairy)	Animal products, low-carb vegetables, nuts, seeds, healthy fats
Plant Foods	Strictly excluded	Allowed within carbohydrate limits
Primary Goal	Elimination, simplicity, and targeting plant-based sensitivities	Ketosis, fat loss, and stable blood sugar

The Role of Protein and Fat

With carbohydrates removed, the carnivore diet relies heavily on protein and fat for energy and satiety. Fattier cuts of meat are often emphasized to provide sufficient calories and fuel for the ketogenic state. Protein provides essential amino acids for muscle repair and other bodily functions. The high fat and protein intake is often cited as the reason many people feel full and experience fewer cravings on this diet.

The diet is composed of approximately 70-80% of calories from fat and 15-30% from protein, with 0-10% from trace carbs.
By focusing on these two macronutrients, the diet aims to stabilize blood sugar and promote a constant fat-burning state.

It is important to note that without proper planning, a carnivore diet can become unbalanced, leading to potential nutrient deficiencies over the long term, such as low levels of magnesium or potassium. Consultation with a healthcare provider is recommended before starting any restrictive diet. For example, the high intake of saturated fats can raise cardiovascular concerns in some individuals. A balanced diet is generally recommended over extreme restrictions. For more information on dietary trends and associated health concerns, the British Heart Foundation provides insightful analysis.

Conclusion

In summary, the carnivore diet eliminates all carbs to induce a metabolic state of ketosis, where the body uses fat for fuel. This zero-carb approach is a consequence of both a philosophical return to an ancestral, plant-free diet and an attempt to eliminate potential plant-based irritants that proponents believe cause health issues. By focusing exclusively on animal-based protein and fat, the diet triggers fat adaptation and relies on gluconeogenesis to supply the body's minimal glucose needs. While popular, especially for its simplicity and potential for short-term weight loss, the diet is highly restrictive and lacks long-term clinical research. This has raised concerns about sustainability and potential nutrient deficiencies, underscoring the need for caution and professional medical guidance.

Frequently Asked Questions

The body can create its own glucose through a process called gluconeogenesis, primarily using amino acids from protein and fatty acids from fat to supply the minimal amount needed for functions like red blood cells.

Reintroducing carbohydrates can pull the body out of ketosis. It may also lead to digestive issues like bloating, gas, or nausea, particularly if the gut has adapted to a plant-free environment.

No, the carnivore diet is an extreme version of a ketogenic diet. While keto limits carbs to around 20-50 grams, carnivore eliminates virtually all plant foods, making it a zero-carb approach.

The carnivore diet has no dietary fiber, as it's only found in plants. Proponents argue that fiber is unnecessary and can even be irritating, while critics warn of potential constipation and gut health issues from its absence.

Some versions of the carnivore diet allow low-lactose dairy products like butter and certain cheeses, while more strict versions, like the 'lion diet,' only permit meat, water, and salt. Dairy contains some carbohydrates in the form of lactose, so it is often limited.

Reported benefits include weight loss, reduced inflammation, improved mental clarity, and relief from autoimmune or digestive issues, although much of the supporting evidence is anecdotal.

Healthcare professionals generally view the carnivore diet as unsustainable and potentially unhealthy in the long term due to its restrictive nature and elimination of entire food groups, which raises concerns about nutrient deficiencies.