What will happen if I only eat meat for 7 days?

November 8, 2025 •

4 min read

Restricting your diet to only meat for a short period, such as 7 days, represents a significant dietary shift. Many people report experiencing a rapid metabolic change as their bodies adapt [1]. If you're wondering what will happen if I only eat meat for 7 days, you can expect your body to undergo a rapid and significant metabolic shift, triggering a range of potential side effects and temporary changes.

Quick Summary

During a 7-day, meat-only diet, your body enters a state of ketosis, leading to initial side effects like fatigue, headaches, and digestive issues. It also excludes fiber and essential vitamins found in plants, posing immediate challenges and potential risks.

Key Points

Initial Discomfort: The first few days of a meat-only diet can cause a 'keto flu' with symptoms like fatigue, headaches, and brain fog as your body shifts from burning carbs to fat [2].
Metabolic Shift to Ketosis: Removing all carbohydrates forces your body into ketosis, a state where fat and ketones become the primary energy source [2].
Nutrient Deficiencies: The diet completely eliminates fiber, vitamin C, and a variety of antioxidants found in plant-based foods, leading to a restricted nutritional profile [1].
Digestive Changes: The lack of dietary fiber can cause significant changes in bowel movements, often leading to constipation and a shift in gut bacteria.
Physiological Stress: High protein intake places extra strain on the kidneys and can alter electrolyte balance, which may lead to muscle cramps and dizziness.
Temporary Weight Loss: Initial weight loss is common but is mostly water weight shed during the depletion of carbohydrate stores [1].
Consult a Professional: Due to its highly restrictive and unbalanced nature, it is crucial to consult a healthcare provider before attempting a meat-only diet [1].

The First 7 Days: A Body in Transition

Embarking on a 7-day, meat-only diet, a short-term version of the carnivore diet, is a dramatic shift for your body. For most people, the typical diet is rich in carbohydrates, which the body prefers to burn for quick energy. By removing all carbohydrates from your diet, you force your body into a state known as ketosis. While this metabolic state is the goal for many low-carb diets, the transition period can be quite uncomfortable and is often referred to as the 'keto flu' or 'carnivore flu' [2].

Days 1–3: The Carb Withdrawal Phase

In the first 72 hours, your body will exhaust its stored glucose, called glycogen, from the liver and muscles. Since carbohydrates bind to water in the body, this process results in a rapid initial weight loss, primarily from water shedding [1].

During this phase, many people experience the most pronounced 'carnivore flu' symptoms as their bodies detox from sugar and struggle to find a new primary fuel source. Common symptoms include [2]:

Fatigue and Brain Fog: Your brain is used to glucose for energy, and the sudden drop-off can leave you feeling sluggish and mentally cloudy.
Headaches and Irritability: Dehydration and electrolyte imbalances due to increased water excretion can cause headaches and mood swings.
Sugar Cravings: The withdrawal from carbohydrates can trigger intense cravings for sugary foods.
Digestive Discomfort: A sudden lack of fiber can cause constipation, though some may experience diarrhea as their gut adapts to the high fat content.

Days 4–5: Entering Ketosis

By the fourth or fifth day, if you have been strict with the diet, your body should be fully producing and running on ketones from fat [2]. At this point, the initial 'flu' symptoms often begin to subside, and some individuals report a feeling of improved mental clarity and increased energy. However, your digestive system may still be adjusting to the lack of fiber. While some report less bloating, others struggle with constipation or bowel changes.

Days 6–7: Stabilization and Continued Adjustment

Near the end of the week, your body is more adapted to using fat as its primary fuel [2]. While the intense symptoms of the first few days have passed, you may still notice ongoing effects. Some people report stable energy levels and reduced hunger due to the high protein and fat content. However, the foundational issues of the diet, such as nutrient deficiencies, begin to become more relevant.

Comparison: 7-Day Meat-Only vs. Balanced Diet


Feature	7-Day Meat-Only Diet	Balanced Diet (with all food groups)
Primary Fuel Source	Body shifts to burning fat (ketones).	Body primarily burns carbohydrates (glucose).
Nutrient Variety	Restricted; lacks vitamins C, K, antioxidants, fiber.	Diverse; provides all essential vitamins, minerals, and phytonutrients.
Dietary Fiber	None; can lead to digestive issues like constipation.	Ample; promotes gut health and regular bowel movements.
Gut Microbiome	Shifts dramatically due to lack of plant fiber.	Supports a diverse and healthy gut flora.
Initial Energy Levels	Often low (keto flu); stabilizes as ketosis is reached.	Stable, with consistent energy from various food sources.
Long-Term Health Risks	Potential for increased LDL cholesterol, kidney strain, and nutrient deficiencies.	Lower risk of chronic diseases like heart disease and cancer when consuming varied whole foods [1].

Potential Risks and Missing Nutrients

While a 7-day period is short, it is important to acknowledge the inherent risks and limitations of this restrictive diet. Even in the short term, you eliminate a wide array of crucial nutrients provided by plant-based foods [1].

Missing Nutrients

Fiber: Found only in plants, fiber is critical for digestive health, bowel regularity, and feeding beneficial gut bacteria. The complete absence can cause significant digestive changes.
Vitamin C: Without fruits and vegetables, intake of this essential vitamin plummets, which can affect immune function and skin health.
Antioxidants and Phytonutrients: These compounds, vital for fighting inflammation and disease, are largely absent from a meat-only diet [1].

Health Risks

Kidney Stress: High protein consumption forces your kidneys to work harder to filter waste products [1]. This can be a concern for individuals with pre-existing kidney issues.
Electrolyte Imbalance: The rapid water loss can deplete key electrolytes like sodium, potassium, and magnesium, leading to muscle cramps, dizziness, and heart palpitations. Drinking bone broth or supplementing electrolytes can help mitigate this.

Conclusion

For a brief period of 7 days, eating only meat will force your body into ketosis, with rapid shifts in energy source and potential water weight loss [2]. The initial days can be marked by the uncomfortable 'carnivore flu' as your body adapts. While some people report improved energy and clarity after the adjustment, this extreme diet completely excludes fiber and a host of essential vitamins and minerals from plant sources. For this reason, medical and nutritional professionals do not recommend this diet due to its restrictive nature and the potential for nutritional deficiencies and health risks [1]. A balanced diet rich in a variety of nutrient-dense whole foods is consistently recommended for long-term sustainable health. For those considering such a significant dietary change, it is always best to consult with a healthcare professional or registered dietitian. You can find more information about balanced diets and risks of dietary fads from authoritative sources [1, 2].

How to Manage the 7-Day Experience

Stay Hydrated: Drink plenty of water to counter the dehydration that occurs with carb restriction. Add salt to your water or consume bone broth to replenish electrolytes.
Replenish Electrolytes: Consider electrolyte supplements or increasing your intake of sodium, potassium (found in meat), and magnesium.
Listen to Your Body: Pay close attention to your energy levels, digestion, and overall well-being. Don't mistake the 'keto flu' for a positive detox and be prepared to stop if symptoms are severe.
Plan Your Re-introduction: After 7 days, re-introduce plant-based foods slowly to avoid digestive shock. Start with easily digestible vegetables.

Optional Link

Ketosis: Definition, Benefits & Side Effects

Frequently Asked Questions

The 'keto flu' refers to a collection of temporary symptoms like fatigue, headache, nausea, and irritability that can occur during the first few days as your body adapts to burning fat instead of carbohydrates for energy [2].

You may experience initial weight loss, but this is largely water weight lost as your body flushes out glycogen stores. Any fat loss depends on your calorie intake, but the satiety from meat can lead to eating less overall [1].

Yes, constipation is a very common side effect due to the complete absence of dietary fiber. Adequate hydration and adding extra fat can sometimes help, but it often persists for short-term followers.

No, a meat-only diet is deficient in several key nutrients, most notably dietary fiber and vitamin C, which are primarily found in plant foods. While organ meats contain some nutrients, it is highly challenging to get all you need without supplementation.

The fatigue and brain fog you experience are due to your body withdrawing from its primary fuel source (glucose) and adapting to a new one (ketones). This adjustment period can temporarily reduce your energy levels [2].

Even a short 7-day stint can put strain on your kidneys due to high protein intake and cause significant nutritional imbalances. Long-term adherence is associated with risks like heart disease and cancer [1].

It is best to reintroduce carbohydrates and plant-based foods gradually to avoid digestive upset. Start with a small amount of easily digestible vegetables and fruits and see how your body reacts before returning to a normal diet.