Protein Intake Calculator — Daily Target by Goal

Protein requirements are not fixed. They exist on a spectrum that shifts with your training goal, and treating them as a single universal number is one of the most common nutrition mistakes in fitness.

The foundation of understanding protein needs is the balance between Muscle Protein Synthesis (MPS) — the process by which your body builds new muscle tissue — and Muscle Protein Breakdown (MPB), the rate at which existing muscle is degraded. Net muscle growth only happens when MPS exceeds MPB. The protein you eat is the primary dietary driver of MPS, which is why intake matters. But how much it matters depends entirely on which direction that MPS/MPB balance is already tilted.

The RDA is not a performance target

The Recommended Dietary Allowance for protein is 0.36g per pound of bodyweight (0.8g/kg). This figure is widely misunderstood. It represents the minimum required to prevent deficiency in sedentary adults — the floor below which muscle loss and nitrogen imbalance occur. It says nothing about what is optimal for someone training to build muscle, preserve lean mass during a cut, or recover from hard sessions multiple times per week. Using the RDA as a fitness target is like using the minimum safe driving speed as your target highway speed.

During a cut: MPB rises, so protein must compensate

When you are in a calorie deficit, MPB increases. Your body, sensing an energy shortfall, begins breaking down muscle tissue for fuel — a process accelerated by cortisol and suppressed insulin. Higher protein intake directly offsets this: it raises MPS enough to counteract the elevated breakdown rate, preserving lean mass even while total calories are restricted. Research supports a target around 1.0g per pound of lean body mass during a cut (Helms et al., 2014, International Journal of Sport Nutrition and Exercise Metabolism). This is approximately 0.9g per pound of total bodyweight for someone carrying average body fat.

During a bulk: 0.8g/lb LBM is sufficient

When you are eating at a surplus and training with progressive overload, MPS is already primed. The anabolic stimulus from resistance training and the energy availability from surplus calories do the heavy lifting. A landmark 2018 meta-analysis by Morton et al. (British Journal of Sports Medicine, PMID 28698222) analyzed 49 randomized controlled trials and found that protein supplementation beyond approximately 0.73g per pound of bodyweight produced no additional gains in muscle mass or strength. This calculator targets 0.8g/lb LBM during a muscle-gain phase — enough to fully support MPS without excess. Eating significantly more does not accelerate growth; the extra protein is simply oxidized for energy.

The "1g per pound" rule and where it goes wrong

The gym convention of eating 1g of protein per pound of bodyweight is harmless but imprecise. It overestimates protein needs by 10–40% depending on your body fat percentage. A 200 lb person at 25% body fat has only 150 lbs of lean mass. At the muscle-gain target of 0.8g/lb LBM, their actual protein need is 120g — not 200g. Hitting 200g is not dangerous, but those extra calories could instead come from carbohydrates that fuel training performance. Precision matters when total calorie targets are tight.

The leucine threshold and meal distribution

Protein timing matters at the meal level. Each meal needs to deliver approximately 2.5–3g of leucine — the branched-chain amino acid that acts as the primary trigger for MPS — to maximally stimulate a muscle-building response. For most high-quality protein sources (chicken, whey, eggs, Greek yogurt), this corresponds to roughly 30–40g of protein per meal. Eating 150g of protein across one or two large meals is less effective than distributing it across four meals, each clearing the leucine threshold. This is why this calculator shows a per-meal target alongside the daily total.

Age and anabolic resistance

Adults over 40 experience what researchers call anabolic resistance — a reduced sensitivity of muscle tissue to the MPS-stimulating effect of dietary protein and resistance training. The same meal that triggers a robust MPS response in a 25 year old produces a blunted response in a 55 year old. To compensate, protein needs increase by approximately 10–20% for equivalent muscle protein synthetic output. If you are over 40, consider targeting the upper end of the range your goal suggests — and prioritize leucine-rich, complete protein sources at each meal.