Do you feel bad when starting a carnivore diet?

According to anecdotal reports, a significant portion of people experience temporary negative symptoms when they first embark on an all-meat eating plan. It is very common to feel bad when starting a carnivore diet, a phenomenon often referred to as the 'carnivore flu'.

Quick Summary

The unpleasant side effects felt when beginning an all-meat diet are known as the 'carnivore flu,' a temporary adaptation phase. These symptoms result from carbohydrate withdrawal and electrolyte imbalance, and can be managed effectively with dietary adjustments and patience.

Key Points

• Carnivore Flu is Normal: Experiencing flu-like symptoms during the first few weeks is a natural part of the body's metabolic shift from burning carbs to fat.

• Electrolytes are Key: Dehydration and electrolyte loss are primary culprits for headaches, fatigue, and muscle cramps; increasing salt, potassium, and magnesium is crucial.

• Increase Your Fat Intake: Eating fattier cuts of meat is essential to provide your body with enough fuel during the adaptation period.

• Patience is a Virtue: The initial discomfort is temporary; most people see significant improvement in energy and clarity within 1 to 3 weeks as their body becomes fat-adapted.

• Stay Hydrated: Drink plenty of water and add salt, or consume bone broth, to combat dehydration and electrolyte loss caused by reduced insulin levels.

• Consider a Gradual Approach: Easing into the diet by first cutting processed foods can reduce the severity of withdrawal symptoms compared to going cold-turkey.

Understanding the Carnivore Flu

When you cut out all carbohydrates and switch to an exclusively animal-based diet, your body undergoes a profound metabolic shift. It transitions from its primary fuel source, glucose from carbs, to burning fat for energy, a state known as ketosis. This adjustment period is what causes the temporary side effects known as the 'carnivore flu.' Unlike a viral infection, these symptoms are a sign of metabolic adaptation, carb withdrawal, and electrolyte changes. Most people experience this phase during the first few weeks, though the duration and severity can vary based on your previous diet, overall health, and how you manage the transition.

What causes the carnivore flu?

The carnivore flu is driven by several key changes in the body:

• Carbohydrate Withdrawal: Your body's initial reaction to eliminating carbs can feel like withdrawal, as the brain and muscles are accustomed to using glucose for fuel. This can lead to fatigue, brain fog, and intense cravings for carbs.
• Electrolyte Imbalance: With lower insulin levels due to the absence of carbs, your kidneys excrete more sodium and water. This rapid loss of electrolytes, including sodium, potassium, and magnesium, is a major contributor to symptoms like headaches and muscle cramps.
• Gut Microbiome Changes: The gut microbiome adapts to the absence of dietary fiber. This dramatic shift in gut bacteria can temporarily cause digestive upset, such as diarrhea, bloating, or constipation, before settling.

Common symptoms during the transition

During the first few weeks, it is normal to experience a variety of symptoms as your body recalibrates:

• Fatigue and Low Energy: This is perhaps the most common symptom, as your body isn't yet efficient at converting fat into a steady energy source.
• Headaches and Dizziness: Often caused by dehydration and the loss of sodium and other electrolytes.
• Digestive Issues: Bloating, diarrhea, or constipation can occur as your digestive system adjusts to a diet with no fiber and a higher fat intake.
• Brain Fog and Irritability: The brain may struggle initially with the shift from glucose to ketones, causing a foggy, slow-thinking sensation or mood swings.
• Muscle Cramps: Electrolyte depletion can lead to involuntary muscle spasms and weakness.

Strategies for a Smoother Carnivore Transition

While the carnivore flu can be unpleasant, several strategies can help minimize symptoms and speed up the adaptation phase. Slowing down the dietary changes, focusing on nutrient-dense foods, and prioritizing hydration are key.

A comparative look: Carnivore flu vs. keto flu

While the experiences are similar, the carnivore flu can be more intense due to the complete elimination of carbs.

Symptom	Carnivore Flu	Keto Flu
Carb Withdrawal	More pronounced due to zero-carb approach.	Present, but less severe with some low-carb foods allowed.
Metabolic Shift	A complete and sudden switch to fat for fuel.	A switch to fat for fuel, but some minimal carb intake can soften the change.
Digestive Changes	Often more significant due to the complete absence of fiber.	May involve changes, but some fiber from low-carb vegetables is still consumed.
Electrolyte Imbalance	More critical to manage due to lack of plant-based sources.	Important to manage, though some plant sources for potassium and magnesium may be retained.

Practical tips to ease the transition

Here is a list of actionable steps to make your adjustment period more comfortable:

• Increase Electrolyte Intake: Generously salt your food and consider drinking bone broth to replenish sodium. Sources of potassium and magnesium are also crucial, so consider organ meats, fatty fish, or a clean electrolyte supplement.
• Hydrate Strategically: Drink plenty of water throughout the day, but remember that sufficient salt intake is necessary for your body to retain that fluid effectively.
• Prioritize Fatty Cuts of Meat: Fat is your new primary energy source. Opt for fattier cuts like ribeye, pork belly, or ground beef (80/20 or higher) to ensure you have enough fuel. Cooking with beef tallow or butter also helps increase fat intake.
• Go Gradual: Rather than a cold-turkey switch, a slower transition can lessen the shock to your system. Gradually reduce processed foods and carbs over a few weeks before fully committing to all animal products.
• Listen to Your Body: During this time, it is wise to reduce the intensity of your exercise routine. Opt for gentler movement like walking until your energy levels stabilize.
• Get Enough Sleep: A good night's rest is critical for helping your body adapt and recover.

Long-term outlook and conclusion

Experiencing unpleasant side effects when starting a carnivore diet is a common and temporary hurdle. The so-called 'carnivore flu' is a sign of your body's metabolic adjustment away from carbohydrates and toward fat for fuel, exacerbated by temporary electrolyte imbalances. By proactively managing your hydration and electrolyte intake, prioritizing fatty animal proteins, and being patient during the 1 to 3-week adaptation period, you can mitigate many of the most uncomfortable symptoms. Remember that listening to your body and making gradual changes are often more successful than abrupt shifts. Once the transition is complete, many people report improvements in energy, mental clarity, and digestion that make the initial discomfort well worth it. For those with underlying health conditions, it's always best to consult a healthcare professional before beginning any restrictive diet. For more detailed information on nutrient sourcing, visit the GoCarnivore website.

Sources

• BBC Science Focus Magazine: The carnivore diet: What eating only meat does to your health…
• CarnivoreSnax: How Long Does Carnivore Flu Last?
• CarnivoreSnax: What are the Short & Long-Term Side Effects of the Carnivore Diet?
• GoCarnivore: What Causes Carnivore Flu? Top 5 Ways to Recover Quickly
• Ancestral Supplements: Carnivore Diet Flu: What It Is and How to Alleviate It
• Chomps: Carnivore Diet Meal Plan & Food List for Beginners
• Carnivore.Diet: Carnivore Diet Side Effects
• CarnivoreSnax: How Long Should You Do Carnivore Diet?
• CarnivoreSnax: How Long Does Carnivore Flu Last? | Carnivore Diet Flu Symptoms
• GoCarnivore: Carnivore Electrolytes: Why They Matter & How to Source Them
• Primal Harvest: Best Electrolytes for Carnivore Diet: A Comprehensive Guide
• Lyteline.com: Electrolyte Drinks on Carnivore Diet: What to Take Daily
• The Gut Health Doctor: Exploring the carnivore diet: a gut health perspective
• Acibadem Health Point: Managing Diarrhea on Carnivore Diet Explained
• CarnivoreSnax: How Long Does Carnivore Flu Last?
• CarnivoreSnax: How Long Does Carnivore Flu Last? | Carnivore Diet Flu Symptoms
• CarnivoreSnax: Why Do I Have No Energy on Carnivore Diet?

Frequently Asked Questions

What is the 'carnivore flu'?

The 'carnivore flu' refers to a temporary set of symptoms, including fatigue, headaches, and digestive issues, that some people experience in the first few weeks of starting a carnivore diet. It is caused by the body's metabolic adjustment from burning carbohydrates to burning fat for fuel.

How long does the adjustment period last?

The adaptation phase, also known as the 'carnivore flu,' typically lasts anywhere from one to three weeks. The duration can be influenced by your previous diet, hydration, and how you manage electrolyte intake.

Why do I feel so tired and lethargic?

Fatigue is common because your body is switching its primary energy source from glucose to fat. Until it becomes more efficient at burning fat (a process called fat adaptation), you may experience lower energy levels.

How can I prevent headaches on the carnivore diet?

Headaches are often caused by electrolyte imbalance, particularly low sodium and dehydration. To prevent them, increase your salt intake, drink plenty of water, and consider incorporating bone broth into your diet.

What can I do about digestive issues like diarrhea or constipation?

Diarrhea or constipation can occur as your gut bacteria adjust to the lack of fiber. Ensure you are adequately hydrated and getting enough fat. Some people find that focusing on fattier cuts of meat helps.

Should I still exercise during the carnivore flu?

It is generally recommended to stick to light activity during the initial adaptation phase. Intense exercise may be too taxing on your body while it is adjusting. Listen to your body and resume more strenuous workouts as your energy stabilizes.

Do I need electrolyte supplements?

While many can get enough electrolytes from salting their food, drinking bone broth, and eating organ meats, some may benefit from a sugar-free electrolyte supplement, especially during the adaptation period or intense exercise.