Why Is Protein Important?
Protein is one of the three essential macronutrients and is responsible for building and repairing virtually every structure in the human body — from muscle fibres and tendons to skin, hair, enzymes, and hormones. Unlike carbohydrates and fat, the body has no dedicated protein storage; it relies on your daily dietary intake to meet its ongoing needs.
Beyond tissue repair, protein has two metabolic properties that make it uniquely valuable for body composition. First, it has the highest thermic effect of food (TEF) of any macronutrient — your body burns approximately 25±30% of the calories from protein just digesting and metabolising it, compared to 6±8% for carbohydrates and 2±3% for fat. Second, protein is significantly more satiating than carbohydrates or fat, making it a powerful tool for managing hunger during a caloric deficit.
For those pursuing body recomposition goals — whether gaining muscle or losing fat — adequate protein intake is non-negotiable. Research consistently shows that protein intakes above the minimum RDA significantly improve outcomes for both muscle retention during weight loss and muscle growth during a surplus.
How Much Protein Do You Need Per Day?
The minimum Recommended Dietary Allowance (RDA) for protein is 0.8 g per kg of body weight — but this represents the minimum required to prevent deficiency, not the optimal amount for anyone with fitness goals. The International Society of Sports Nutrition (ISSN) recommends 1.4–2.0 g/kg for exercising individuals, with 1.6–2.0 g/kg as the target for maximising muscle protein synthesis.
The optimal amount varies based on your goal, training intensity, age, and whether you are in a caloric surplus or deficit. Our calculator uses goal-specific multiplier ranges so you can see both the minimum and maximum recommended intake for your situation, which is more scientifically accurate than a single fixed number.
Protein for Muscle Building
To maximise muscle protein synthesis (MPS) — the process by which your body builds new muscle tissue — you need 1.6–2.0 g of protein per kg of body weight per day. A landmark 2017 meta-analysis by Morton et al. in the British Journal of Sports Medicine confirmed that protein intakes beyond 1.62 g/kg/day produced diminishing additional returns for muscle gain in most individuals. However, protein intakes of up to 2.2 g/kg are routinely used by elite athletes and are considered safe and beneficial.
Distributing protein intake across 3–5 meals of 20–40 g each (rather than consuming it all at once) optimises MPS throughout the day. This is why our calculator provides a "per meal" estimate based on dividing the daily target by four servings. Use our TDEE Calculator to set your total calorie target before calculating your protein needs.
Protein for Weight Loss
During a caloric deficit, high protein intake (2.0–2.4 g/kg) is particularly important because it helps preserve lean muscle mass that would otherwise be broken down for energy. Studies show that individuals following high-protein diets during weight loss retain significantly more muscle and lose more fat than those consuming standard protein levels. The higher end of the range also maximises the satiety effect, reducing the likelihood of overeating. Combine your protein target with your macronutrient ratios using our Macro Calculator.
Best High-Protein Foods
Achieving your daily protein target is most straightforward when you prioritise high-protein whole foods. Top sources include:
- Chicken breast — 31 g protein per 100 g, lean and versatile
- Greek yogurt — 10 g per 100 g, easy snack or breakfast
- Eggs — 6 g per egg, highly bioavailable complete protein
- Tuna / salmon — 25–27 g per 100 g, rich in omega-3s
- Cottage cheese — 12 g per 100 g, slow-digesting casein
- Lentils / chickpeas — 8–9 g per 100 g, high-fibre plant option
- Whey protein powder — 20–25 g per scoop, convenient supplement
Protein supplements can be useful when whole food sources are impractical, but they are not necessary if your diet already meets your target. Calculate your full calorie and macronutrient baseline with our BMR Calculator.
How to Hit Your Protein Target
Consistently meeting your daily protein target requires planning. Start by calculating your target with this calculator, then use a food tracking app to log meals until you have an intuitive sense of the protein content in your regular foods. Aim to include a protein source in every meal and snack. Preparing protein-rich meals in advance (batch cooking chicken, hard-boiling eggs, portioning Greek yogurt) removes the friction of hitting your target on busy days.
Scientific References: Thomas DT, et al. (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and ACSM: Nutrition and Athletic Performance. J Acad Nutr Diet. 116(3):501–528. — Morton RW, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training–induced gains. Br J Sports Med. 52(6):376–384.