How Much Protein Do You Need?
Protein is the only macronutrient that builds and repairs muscle tissue. The central question — how much protein do you actually need? — has been intensively researched over the past 30 years. The answer depends on your goals, bodyweight, training intensity, and age. For sedentary adults, the minimum is 0.8 g/kg. For anyone actively training to build or preserve muscle, the evidence consistently points to 1.6–2.2 g/kg as the optimal range — roughly double the average person's intake.
- The Evidence-Based Target: 1.6–2.2 g of protein per kg of bodyweight per day maximises muscle protein synthesis for most exercising adults.
- More Does Not Always Mean More Muscle: Beyond 2.2 g/kg, additional protein provides no further anabolic benefit and is simply used as fuel or excreted.
- Spreading Intake Matters: Protein synthesis responds best to 3–5 daily servings of 20–40 g of high-quality protein, not a single large dose.
The Protein Dose-Response Curve
The relationship between protein intake and muscle protein synthesis (MPS) is not linear — it follows a dose-response curve that eventually plateaus. Below ~0.8 g/kg, muscle maintenance begins to fail. Between 0.8 g/kg and 1.6 g/kg, MPS increases steadily. Between 1.6 g/kg and 2.2 g/kg, you approach the plateau — marginal gains still exist. Beyond 2.2 g/kg, the additional protein is oxidised for energy. There is no anabolic benefit to eating 3 g/kg; you are simply burning expensive protein as fuel.
Protein Requirements by Goal and Activity Level (g per kg bodyweight)
Daily Maintenance Calorie Formula
| Symbol | Meaning & Description |
|---|---|
| TDEE | Total Daily Energy Expenditure (Maintenance calories) |
| BMR | Basal Metabolic Rate calories per Mifflin-St Jeor |
| Act | Activity Multiplier (ranges from 1.2 to 1.9) |
BMR = 10 × 70kg + 6.25 × 175cm - 5 × 25yr + (5) = 1674 kcal
TDEE = BMR × Activity Multiplier = 1674 × 1.375 = 2,301 kcal/day
For safe weight loss (deficit -500kcal): 1801 kcal. For safe weight gain (surplus +500kcal): 2801 kcal.
Calculating Your Personal Protein Target
Step 1: Determine your bodyweight in kilograms.
Step 2: Select your target ratio based on goal (see Decision Framework below).
Step 3: Multiply.
Example A — 75 kg male, building muscle (bulking):
At 4 kcal per gram, this is 600 kcal from protein alone.
Example B — 65 kg female, fat loss phase (deficit):
The higher end of the range is used during a deficit to aggressively protect lean muscle from catabolism.
Example C — 80 kg recreational runner, general fitness:
The Brick and Mortar Analogy
Your muscle fibres are the bricks of a wall. Training is the demolition crew — it creates micro-tears in existing muscle fibres. Protein is the mortar and new bricks that the construction crew (muscle protein synthesis) uses to repair the damage and build the wall higher. If you train (demolish) without adequate protein (building materials), the crew cannot rebuild the wall — your muscles are damaged but not repaired, leading to muscle loss over time.
- Muscle Building: During a calorie surplus, 1.8–2.2 g/kg of protein ensures that the additional calories drive muscle protein synthesis rather than pure fat deposition. Without adequate protein, a calorie surplus primarily produces fat gain.
- Fat Loss with Muscle Preservation: During a calorie deficit, protein needs increase, not decrease. At 2.0–2.4 g/kg, the body preferentially burns fat and spares muscle even as total calories drop.
- Ageing and Sarcopenia Prevention: Adults over 60 experience anabolic resistance — their muscles respond less effectively to protein signals. Research suggests older adults need 1.6–2.0 g/kg (vs. 1.2 g/kg previously recommended) to maintain muscle mass.
- Plant-Based Athletes: Because plant proteins have lower leucine content and digestibility, plant-based athletes should target the upper end of the range (2.0–2.4 g/kg) and prioritise leucine-rich plant sources (soy, tempeh, edamame).
- The "RDA Is Enough" Myth: The Recommended Dietary Allowance (RDA) of 0.8 g/kg is the minimum to prevent deficiency in sedentary adults — not the optimal level for muscle retention or athletic performance. Anyone who exercises regularly needs significantly more.
- One Giant Protein Meal: Muscle protein synthesis has a per-meal ceiling of approximately 35–45 g of protein. Eating 150 g of protein in one sitting does not produce 4× the MPS of a 35 g meal. Distributing protein across 4–5 meals maximises total daily synthesis.
- Ignoring Protein Quality: Not all protein is equal. Leucine content is the key driver of MPS. Animal proteins (eggs, chicken, whey) are leucine-rich. Plant proteins (most legumes) have lower leucine per gram of protein.
- Drinking Shakes to "Hit Macros" Without Food Quality: Relying entirely on protein powder ignores the micronutrients (zinc, iron, B vitamins) that come with whole-food protein sources. Protein powder should supplement, not replace, whole foods.
AAnimal Protein Sources
Animal proteins — eggs, chicken, beef, fish, dairy — are "complete proteins" containing all 9 essential amino acids in proportions closely matching human muscle needs. They are rich in leucine (the primary trigger for MPS), highly bioavailable (90–99% absorbed), and generally calorie-efficient per gram of protein. A 200 g chicken breast provides roughly 50 g of protein.
BPlant Protein Sources
Plant proteins — legumes, lentils, tofu, tempeh, seitan, quinoa — provide protein alongside fibre, phytonutrients, and lower saturated fat. Most are "incomplete" proteins (low in one or more essential amino acids) but combining sources (e.g. rice + beans) creates a complete amino acid profile. Plant proteins have lower bioavailability (60–80%) and lower leucine density, requiring higher total intake to achieve equivalent MPS.
Protein Target by Goal and Activity
| Goal / Profile | Protein Target (g/kg bodyweight) | Notes |
|---|---|---|
| Sedentary adult, no training goal | 0.8–1.0 | Minimum to prevent deficiency |
| Light activity / general health | 1.2–1.4 | Better for overall health vs. RDA minimum |
| Recreational exerciser | 1.4–1.6 | Most gym-goers fall here |
| Muscle building (calorie surplus) | 1.8–2.2 | Support hypertrophy and limit fat gain |
| Fat loss (calorie deficit) | 2.0–2.4 | Higher targets protect lean mass during restriction |
| Adult 60+ (sarcopenia prevention) | 1.6–2.0 | Older muscle has reduced anabolic sensitivity |
| Plant-based athlete | 2.0–2.4 | Compensate for lower leucine density and bioavailability |
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