How much protein do I need per day?

The RDA of 0.8 g/kg is a minimum to prevent deficiency, not optimal. Active adults need 1.2–1.6 g/kg. People building muscle should target 1.6–2.2 g/kg (0.7–1.0 g/lb). Cutting calories? Aim higher — 2.2–2.6 g/kg — to preserve lean mass while losing fat. Older adults benefit from 1.2–1.5 g/kg minimum to fight sarcopenia.

Is too much protein bad for kidneys?

For people with healthy kidneys, no. A 2018 systematic review found high-protein diets up to 2.8 g/kg do not harm kidney function in healthy adults. Anyone with chronic kidney disease should follow their nephrologist's protein limit (typically 0.6–0.8 g/kg).

How should I split protein across meals?

Distribute roughly evenly across 3–5 meals, each containing 0.4 g/kg (about 25–40 g for most adults). Muscle protein synthesis is maximised by ~3 hourly doses around the leucine threshold (~2.5 g leucine). Eating all your protein in one meal works but is suboptimal for muscle building.

What are the best protein sources?

Highest quality (complete amino acid profile, high digestibility): chicken breast, eggs, Greek yogurt, lean beef, fish, whey protein, cottage cheese. Plant sources: soy, tofu, tempeh, lentils, chickpeas, quinoa. Vegans should slightly increase total protein (1.2× factor) to compensate for lower digestibility scores.

Do I need a protein shake?

No — but they're convenient. If you can hit your daily target through whole food, you don't need supplements. Whey or pea protein helps when you're travelling, post-workout, or struggling to reach 30 g per meal. Aim to get most protein from food first.

🍗 Protein Intake Calculator

Daily protein needs in grams based on your bodyweight and goal. Includes recommended per-meal split for muscle protein synthesis.

Units

Bodyweight (kg)

Goal

Meals per day

⚠️ General guidance. People with chronic kidney disease, on dialysis, or with specific medical conditions should follow their physician's protein limit. Pregnancy, breastfeeding and elite training have specific needs — consult a registered dietitian.

Why Protein Matters

Protein is the only macronutrient your body cannot store in any meaningful way. Every cell — muscle, skin, hair, enzymes, hormones, immune antibodies — needs a constant supply of amino acids. Hitting an adequate daily protein intake is the single most impactful nutrition variable for body composition, recovery from training, satiety on a diet, and (in older adults) muscle preservation.

How Much Do You Actually Need?

The 0.8 g/kg RDA is the minimum to prevent deficiency, not the optimum. Modern sports-nutrition consensus (ISSN, 2017):

Sedentary adults: 0.8–1.0 g/kg
Active adults / general fitness: 1.2–1.6 g/kg
Building muscle: 1.6–2.2 g/kg (0.7–1.0 g/lb)
Cutting (fat loss): 2.2–2.6 g/kg — higher to spare lean mass while in a deficit
Endurance athletes: 1.4–2.0 g/kg
Adults 50+: 1.2–1.5 g/kg minimum to combat age-related muscle loss

Distribute Across Meals

Muscle protein synthesis appears maximised by spreading protein across 3–5 meals, each containing roughly 0.4 g/kg. For an 80 kg person that's about 32 g per meal — the equivalent of one chicken breast, a large can of tuna, or 200 g of Greek yogurt. Eating all your protein in one giant dinner technically meets the daily total, but you'll build less muscle.

Quality Matters Too

Protein quality is measured by DIAAS (Digestible Indispensable Amino Acid Score). Whey, milk, eggs and beef all score above 100. Most plant proteins score lower (lentils ~60, peanuts ~43) because they're missing one or more essential amino acids. Vegans should aim slightly higher total intake (~1.2× factor) and combine sources (rice + beans, oats + soy) for a complete amino acid profile.

Common Myths

"High protein damages kidneys" — only true if you already have CKD. Healthy kidneys handle up to 2.8 g/kg without issue.
"You can only absorb 30 g per meal" — false. You absorb all protein eaten; the question is just how efficiently it's used for muscle synthesis (which plateaus around 0.4 g/kg per meal).
"You need a shake immediately after training" — the post-workout 'anabolic window' is closer to 4–6 hours, not 30 minutes. Daily total matters far more than timing.

Pair with TDEE & Macros

Protein is one leg of the macro stool. Combine this calculator with our TDEE Calculator for total calories and the Macro Calculator for the carb/fat split.

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Important Note: These are general guidelines for healthy adults. Anyone with chronic kidney disease, liver disease, or undergoing dialysis should follow their nephrologist's specific protein limit. Pregnancy, breastfeeding, and youth athletes have additional needs — consult a registered dietitian.

Related Calculators

Daily Calorie Calculator — TDEE based on age, weight, height and activity level.
Macro Calculator — Daily protein, carbs and fat split with cut/maintain/bulk presets and four split styles.
TDEE Calculator — Total Daily Energy Expenditure with BMR + cut/maintain/bulk targets.