What do you call a diet with no carbs?

December 17, 2025 •

3 min read

According to StatPearls, studies have shown that very low-carb, ketogenic diets can induce rapid weight loss for the first 6 to 12 months. But what do you call a diet with no carbs? This type of eating plan often refers to a ketogenic diet, though a stricter, zero-carb version is known as the carnivore diet.

Quick Summary

A diet with almost no carbs is most commonly a ketogenic (keto) diet, which severely restricts carbohydrates to induce ketosis. A more extreme version that excludes all plant-based foods is called the carnivore diet. Both focus on protein and fat for fuel.

Key Points

Ketogenic Diet: A very low-carb eating plan that restricts carbs to 20-50 grams daily, forcing the body into a metabolic state called ketosis.
Carnivore Diet: An extreme, zero-carb diet composed exclusively of animal products like meat, fish, and eggs.
Ketosis Explained: A metabolic state where the body burns fat for energy instead of glucose, producing ketone bodies.
Keto Flu: Common initial side effects of very low-carb diets, including fatigue, headache, and nausea, as the body adjusts.
Long-term Risks: Very restrictive diets can lead to nutrient deficiencies, potential kidney and heart issues, and poor long-term adherence.
Dietary Differences: The keto diet allows for low-carb vegetables, nuts, and seeds, while the carnivore diet eliminates all plant-based foods.

A true "no carb" diet is exceptionally rare, and most people who refer to this method are actually following a ketogenic or carnivore eating plan, which are better defined as very low-carbohydrate diets. In these diets, the body shifts its primary energy source from glucose (from carbs) to fat, a metabolic state known as ketosis. Understanding these distinctions is crucial for anyone considering such a restrictive eating style.

The Ketogenic (Keto) Diet

The ketogenic diet is a high-fat, moderate-protein, and very low-carb eating plan. To trigger ketosis, daily carbohydrate intake is typically limited to 20–50 grams. This forces the body to produce ketone bodies from fat stores, which are then used for energy by the brain and muscles.

How the keto diet works

Carb restriction: Carbohydrate intake is drastically reduced, depleting the body's glycogen (stored glucose) reserves.
Fat for fuel: With glucose levels low, the liver begins breaking down fat into ketones to serve as an alternative energy source.
Entering ketosis: This metabolic shift is called nutritional ketosis, and it is the central goal of the keto diet.

Foods on a ketogenic diet

Allowed: Meat, fatty fish, eggs, cheese, butter, oils (olive, avocado), nuts, seeds, and low-carb vegetables like leafy greens and broccoli.
Restricted: Sugary foods, grains, starches, most fruits, legumes, and root vegetables.

The Carnivore (Zero Carb) Diet

The carnivore diet takes carbohydrate restriction to its most extreme conclusion, aiming for zero carbs by excluding all plant-based foods. This eating plan consists exclusively of animal products.

What to expect on the carnivore diet

Elimination of plants: All fruits, vegetables, grains, nuts, and seeds are removed from the diet, along with sugar and most dairy.
Animal products only: The menu is limited to meat, fish, eggs, and some select dairy items.
Extreme ketosis: Due to the almost total lack of carbohydrates, followers of this diet enter a deep state of ketosis.

Comparison of Very Low-Carb Diets


Feature	Ketogenic (Keto) Diet	Carnivore (Zero Carb) Diet
Carbohydrate Intake	20–50g per day from low-carb sources.	Zero, or near-zero, carbs from any source.
Primary Energy Source	Fat, converting to ketones.	Fat, converting to ketones.
Food Variety	Includes meat, fish, eggs, dairy, nuts, seeds, and low-carb vegetables.	Limited to only animal products (meat, fish, eggs, etc.).
Fiber Content	Can be adequate with smart choices of low-carb vegetables.	Non-existent, potentially causing digestive issues.
Nutrient Deficiencies	Risks exist, but can be mitigated with a diverse range of keto-friendly foods.	Higher risk of deficiencies in vitamin C, fiber, and others found in plants.
Dietary Flexibility	Moderate, as certain plant foods are included.	Very low, as all plant foods are prohibited.

Potential Risks and Health Considerations

Both ketogenic and carnivore diets are highly restrictive and can lead to side effects. The initial period, often called the "keto flu," can cause headaches, fatigue, and nausea as the body adapts to burning fat for fuel. Long-term concerns for very low-carb diets include potential nutrient deficiencies, kidney stones, and adverse effects on heart health due to high intake of saturated fats.

It is highly recommended to consult a healthcare professional before starting any restrictive diet. Long-term studies on the effects of these diets, especially the carnivore diet, are limited, and sustainability is a major challenge. Instead of a one-size-fits-all approach, a balanced, whole-food diet is often considered the most sustainable and healthy option for long-term wellness. For those exploring options, resources like the Harvard T.H. Chan School of Public Health offer balanced dietary guides.

Conclusion: Defining the 'No Carb' Approach

When someone asks "what do you call a diet with no carbs?", the most accurate answer involves distinguishing between the ketogenic and carnivore diets. The ketogenic diet represents a very low-carb approach that is popular for weight loss, while the carnivore diet is an extremely restrictive, zero-carb plan based entirely on animal products. Both diets force the body into ketosis, but they differ significantly in their long-term sustainability, nutritional completeness, and flexibility. While some individuals may see short-term benefits from these methods, they come with notable risks and challenges. A balanced diet remains the gold standard for long-term health and wellness, but for those who choose a very low-carb path, understanding the differences and potential consequences is essential.

Frequently Asked Questions

A 'no carb' diet is often used loosely to describe a ketogenic or keto diet, but it is not the same. The keto diet typically limits carbs to 20-50 grams per day, whereas a strict 'no carb' plan like the carnivore diet aims for zero grams.

With severely restricted carbohydrates, the body runs out of its primary fuel source (glucose) and enters a metabolic state called ketosis. It then burns stored fat for energy, producing molecules called ketones.

The carnivore diet is a more extreme form of a low-carb diet where followers eat only animal products, including meat, fish, and eggs. It excludes all plant-based foods.

Long-term safety is a concern for highly restrictive, no-carb diets like the carnivore diet. They can lead to nutrient deficiencies, potential heart health issues from high saturated fat intake, and are often difficult to sustain.

The 'keto flu' refers to a group of short-term side effects that can occur when starting a very low-carb diet. Symptoms may include fatigue, headaches, irritability, and nausea as your body adapts to burning fat instead of carbs.

On a ketogenic diet, yes, you can eat low-carb vegetables like leafy greens and broccoli. On a strict carnivore or zero-carb diet, all vegetables are eliminated.

The main risks include potential nutrient deficiencies (especially fiber, vitamin C, and antioxidants), high saturated fat intake, and a lack of sustainability due to its highly restrictive nature.