carnivore diet calculator

What this carnivore diet calculator does

This calculator gives you a practical starting point for a carnivore or near-zero-carb diet by estimating daily calories and splitting those calories into protein, fat, and optional trace carbs. It is useful if you want to lose fat, maintain weight, or gain muscle while eating mostly animal-based foods like beef, eggs, fish, poultry, and dairy (if tolerated).

Instead of guessing portions every day, you get numeric macro targets that you can translate into real meals. That means less confusion and easier tracking.

How the calculator works

1) Energy needs (calories)

The calculator estimates your basal metabolic rate (BMR) using the Mifflin-St Jeor equation, then multiplies by an activity factor to estimate total daily energy expenditure (TDEE). From there, calories are adjusted based on your goal:

• Fat loss: roughly 20% calorie deficit
• Maintain: around maintenance calories
• Muscle gain: roughly 10% calorie surplus

2) Protein target

Protein is prioritized because it supports lean mass, satiety, and recovery. The calculator uses a grams-per-kilogram multiplier based on goal, with fat loss requiring a slightly higher protein ratio to protect muscle.

3) Fat target

After protein (and optional carbs) are set, remaining calories are assigned to fat. A minimum fat floor is enforced to avoid extremely low-fat plans, which are often hard to sustain on a carnivore approach.

How to use your numbers in real life

You do not need to be perfect. Use your targets as a weekly average, not a rigid daily rule. If your protein target is 170g and fat target is 140g, being within about 10% most days is typically good enough for progress.

• Hit protein first.
• Adjust fat up or down to control total calories.
• Keep carbs where your digestion, energy, and adherence feel best.
• Track trends (body weight, waist, strength, energy) for 2–3 weeks before making big changes.

Carnivore macro examples by goal

Fat loss phase

Keep protein high, keep carbs very low, and use fat as the main adjustment lever. If fat loss stalls for 2+ weeks, reduce fat slightly (for example, less added butter/tallow), not protein.

Maintenance phase

Keep protein adequate and increase fat to support energy. This is a great phase to stabilize appetite, digestion, and training performance before another cut or gain cycle.

Muscle gain phase

Maintain high protein and increase fat enough to create a modest calorie surplus. Pair this with progressive overload strength training and adequate sleep.

Electrolytes matter on low-carb and zero-carb diets

Many “keto flu” symptoms are electrolyte related, especially when carbs drop quickly. Make sure you consistently get:

• Sodium: often higher than expected on low-carb plans
• Potassium: from foods and/or clinician-guided supplementation
• Magnesium: especially useful for sleep, muscle function, and cramp prevention
• Hydration: drink to thirst, and include electrolytes as needed

Common mistakes with carnivore planning

• Undereating overall calories for too long
• Eating too little protein and relying mainly on fat
• Changing macro targets every few days instead of evaluating weekly trends
• Ignoring sleep quality, stress, and training load
• Expecting immediate body-composition changes without consistency

Frequently asked questions

Do I need to eat exactly 0 carbs?

Not necessarily. Some people do best with strict zero-carb, while others perform better with a small amount (for example, 10–20g/day) from animal-based sources. Pick the level you can sustain.

Should I eat one meal or multiple meals?

Meal frequency is flexible. The calculator provides per-meal targets so you can split macros across 1–4 meals based on appetite and schedule.

How often should I update my targets?

Recalculate every 4–6 weeks, or sooner if body weight changes by about 5% or your activity level changes significantly.

Important note

This tool is for educational use and does not replace medical advice. If you are pregnant, breastfeeding, have kidney disease, diabetes, cardiovascular disease, or take medication affected by diet changes, consult a qualified healthcare professional before starting a carnivore diet.