Nutrition Diet: What is the famous diet with no carbs?

October 8, 2025 •

4 min read

According to Harvard Health, the carnivore diet is sometimes referred to as the “zero carb” diet due to its extreme restriction of carbohydrates. This famous diet with no carbs has gained a significant following, with proponents claiming various health improvements by consuming only animal products.

Quick Summary

The carnivore diet eliminates all plant-based foods, focusing exclusively on animal products, which leads to a near-zero carb intake. This article explores the principles, food lists, and potential health implications of the carnivore diet, contrasting it with the more flexible ketogenic diet. It discusses the metabolic state of ketosis induced by these plans, alongside the nutritional challenges and risks associated with severe carb restriction. Ultimately, this overview aims to inform readers about the nature of these restrictive eating approaches.

Key Points

The Carnivore Diet: Often called the 'zero-carb' diet, this eating plan restricts consumption to only animal products like meat, fish, and eggs.
Ketogenic (Keto) Diet: A popular very low-carb alternative that limits carbs to 20-50 grams per day, allowing some plant foods like leafy greens.
Ketosis: Both diets can induce ketosis, a metabolic state where the body burns fat for fuel instead of glucose, but a true keto diet has specific macronutrient ratios.
Nutrient Deficiencies: Strict no-carb diets risk significant deficiencies in fiber, vitamin C, and other essential nutrients found in plants.
Health Concerns: Risks associated with long-term, high-fat, high-protein diets include increased LDL cholesterol, potential kidney stress, and digestive issues.
Medical Consultation: Due to the restrictive nature and potential risks, it is crucial to consult a healthcare provider or registered dietitian before starting a no-carb or very low-carb diet.

Understanding the Concept of 'No Carbs'

While the idea of a 'no carb' diet is popular, a truly zero-carbohydrate intake is extremely difficult to achieve and maintain, as even animal products can contain trace amounts. The most famous eating plan that comes closest is the carnivore diet, which restricts all food to animal-based sources. For most people seeking to drastically reduce carbs, the ketogenic (keto) diet is a more widely known and studied option, though it is very low-carb rather than zero-carb.

The Carnivore Diet: The Ultimate Low-Carb Approach

The carnivore diet is an elimination diet that permits only the consumption of animal products. The central idea is that by cutting out all carbohydrates, especially processed foods and sugars, the body can reach an optimal state for weight management and reducing inflammation.

Allowed foods on the carnivore diet:

Meat (beef, lamb, pork)
Poultry (chicken, turkey)
Fish and seafood (salmon, mackerel, sardines)
Eggs
Animal fats (tallow, lard, butter)
Bone marrow and bone broth
Some dairy, though strict followers may exclude it
Water, coffee, and tea (plain)

Advocates of this diet often report simplified meal planning, reduced cravings, and improved mental clarity. However, it is an extremely restrictive approach that eliminates entire food groups known for essential nutrients, like fiber, vitamins, and minerals.

The Ketogenic Diet: Low-Carb, High-Fat

The ketogenic diet, or keto, is a very low-carb, high-fat, and moderate-protein eating plan. Unlike the carnivore diet, it does not eliminate all plant foods. Instead, it aims to keep carbohydrate intake to a minimal level, typically between 20 and 50 grams of net carbs per day, to trigger a metabolic state called ketosis. In ketosis, the body shifts from using glucose (from carbs) to using fat for energy.

Typical keto diet macronutrient ratios:

Fat: 70–80% of daily calories
Protein: 10–20% of daily calories
Carbohydrates: 5–10% of daily calories

This approach allows for a wider variety of foods, including leafy greens, nuts, seeds, and healthy oils, while still being restrictive enough to induce ketosis.

Comparing the Carnivore and Ketogenic Diets


Feature	Carnivore Diet (Zero-Carb)	Ketogenic (Keto) Diet
Carb Intake	Near-zero grams (only trace amounts)	20–50 grams per day (very low)
Allowed Foods	Exclusively animal products: meat, fish, eggs, animal fat	Includes low-carb vegetables, nuts, seeds, some dairy, and healthy oils
Plant Foods	Strictly prohibited	Allowed within carb limits, especially non-starchy vegetables
Primary Goal	Elimination of potential plant-based food sensitivities; simplicity	Induce ketosis for weight loss and blood sugar control
Ketosis Induction	High chance due to near-zero carbs	Careful macronutrient tracking required
Nutrient Concerns	High risk of deficiencies (e.g., fiber, vitamin C)	Possible deficiencies (e.g., electrolytes), requires planning
Flexibility	Extremely limited, strict adherence required	More flexible, offers wider variety of foods

Potential Health Benefits and Significant Risks

Both diets can lead to rapid weight loss and improved blood sugar control in the short term, primarily by eliminating refined carbohydrates and sugar. However, these benefits must be weighed against significant risks and potential downsides.

Potential benefits:

Rapid weight loss: Initially, this includes water weight loss due to reduced glycogen stores.
Improved blood sugar control: Cutting carbs drastically can reduce blood sugar and insulin levels, beneficial for individuals with type 2 diabetes under medical supervision.
Increased satiety: The high protein and fat content can increase feelings of fullness, potentially reducing overall calorie intake.

Significant risks and concerns:

Nutrient Deficiencies: Eliminating entire food groups on a carnivore diet removes crucial sources of vitamins, minerals, and fiber, potentially leading to long-term health issues. The ketogenic diet also requires careful planning to avoid deficiencies.
'Keto Flu': The transition to ketosis can cause side effects like fatigue, headaches, dizziness, and irritability.
Digestive Issues: Lack of fiber can lead to constipation in the long term for both diets, though some carnivore adherents report the opposite.
High Saturated Fat Intake: Consuming a diet very high in saturated fats can raise LDL ('bad') cholesterol, increasing heart disease risk for some individuals.
Kidney Stress: Very high protein intake can place a burden on the kidneys over time.
Unsustainability: The restrictive nature of both diets makes long-term adherence challenging for many people.

Conclusion: The Importance of a Balanced Approach

While the carnivore diet represents the most famous example of a nearly no-carb eating plan, it is an extreme and highly restrictive approach. The ketogenic diet offers a slightly more flexible low-carb alternative, but both carry significant nutritional risks if not managed correctly. Long-term studies on the safety of the carnivore diet are lacking, making it a particularly risky strategy. For most individuals, eliminating refined sugars and processed foods is a more sustainable and less risky path to improved health. Always consult a healthcare professional before starting a diet this restrictive, especially if you have pre-existing health conditions. Sustainable, balanced eating is generally more effective for lasting health than extreme elimination.

For more in-depth information on the carnivore diet's potential risks and health implications, visit Harvard Health: What is the carnivore diet?.

Frequently Asked Questions

A diet that is 100% free of carbohydrates is nearly impossible to achieve, as even some animal products may contain trace amounts. The carnivore diet is the most famous plan that aims for a near-zero carb intake by eliminating all plant-based foods.

The keto diet is a very low-carb plan that allows some plant foods like leafy vegetables, nuts, and seeds, targeting a specific macronutrient ratio to induce ketosis. In contrast, the carnivore diet is an all-animal product plan that aims for near-zero carbs, with no specific macro tracking.

Many people experience what's known as the 'keto flu' during the transition to ketosis, which includes symptoms like fatigue, headaches, dizziness, and irritability. Constipation and bad breath can also occur.

Yes. Eliminating entire food groups like fruits, vegetables, and whole grains removes important sources of vitamins, minerals, and dietary fiber. This can lead to deficiencies in nutrients like vitamin C, potassium, and magnesium.

Yes, due to the extreme restrictiveness and potential for nutritional deficiencies and other health risks, medical supervision from a healthcare provider or dietitian is highly recommended.

For many, the highly restrictive nature of these diets makes them difficult to sustain long-term. The lack of variety can lead to food cravings and social difficulties, making more balanced eating patterns easier to maintain over time.

Diets very high in saturated fats, like the carnivore diet, can increase LDL ('bad') cholesterol in some individuals, which may elevate the risk of heart disease. It is important to focus on healthy, unsaturated fats where possible.