Protein Calculator

Find your daily protein target based on body weight, fitness goal, and activity level — with per-meal breakdowns and real-food equivalents.

Protein Ranges by Goal

General Health0.8–1.2 g/kg/day
Adequate for maintaining lean mass and supporting basic metabolic function.
Muscle Building1.6–2.2 g/kg/day
Supported by meta-analyses on resistance-trained individuals for maximizing muscle protein synthesis.
Fat Loss1.2–1.6 g/kg/day
Higher protein preserves lean mass during a caloric deficit and increases satiety.
Endurance / Cardio1.2–1.4 g/kg/day
Supports muscle repair after aerobic training and fuels gluconeogenesis during long efforts.
Healthy Aging (50+)1.2–1.5 g/kg/day
Counteracts anabolic resistance and sarcopenia; more protein is needed per meal to stimulate MPS.

Why Protein Needs Increase With Age

After roughly age 50, muscle tissue becomes progressively less responsive to the anabolic signal of dietary protein — a phenomenon called anabolic resistance. Older adults need a higher dose of leucine (the key amino acid that triggers muscle protein synthesis) to achieve the same MPS response as a younger person.

Without sufficient protein, the body enters a slow negative balance where muscle breakdown outpaces synthesis — the root mechanism of sarcopenia (age-related muscle loss). Sarcopenia is independently associated with falls, insulin resistance, longer hospital stays, and all-cause mortality.

Research by Paddon-Jones & Rasmussen (2009) and the PROT-AGE study group recommends 1.0–1.2 g/kg/day as a minimum for healthy older adults, rising to 1.2–1.5 g/kg/day or higher when combined with resistance training.

Protein Timing: What the Science Actually Says

The old "anabolic window" (consume protein within 30 minutes post-workout or lose gains) has been largely debunked. A 2013 meta-analysis by Schoenfeld et al. found that total daily protein intake is far more important than timing for muscle hypertrophy when diet is controlled.

That said, distribution does matter at the meal level. Most studies show a minimum of 20–30g per meal is required to maximally stimulate muscle protein synthesis — because leucine threshold must be crossed. Spreading protein across 3–4 meals therefore outperforms eating the same total in 1–2 large meals.

Pre-sleep protein (20–40g of casein or equivalent) has been shown in several RCTs to increase overnight MPS without disrupting body composition — useful for those training to build muscle or preserve lean mass during a cut.

Frequently Asked Questions

How much protein do I need per day?
It depends on your goal: 0.8 g/kg for general health, 1.6-2.2 g/kg for muscle building, 1.2-1.6 g/kg for fat loss, and 1.2-1.5 g/kg for adults over 65.
Can I eat too much protein?
For people with healthy kidneys, high protein intake up to 2.2 g/kg is well-studied and safe. Those with existing kidney disease should consult their doctor about appropriate limits.
Does protein timing matter?
Total daily intake matters most. But spreading protein across 3-4 meals with at least 20-30g per meal optimizes muscle protein synthesis throughout the day.
Is plant protein as good as animal protein?
Per gram, animal protein has a more complete amino acid profile and higher leucine content. But combining plant sources (legumes + grains) achieves equivalent results.
Why do older adults need more protein?
Anabolic resistance means aging muscles require a stronger protein stimulus to maintain mass. Higher intake (1.2-1.5 g/kg) plus resistance training helps prevent sarcopenia.

Log meals and track daily protein with Vitalix AI nutrition

Vitalix logs every meal, tallies protein in real time, and shows you whether you hit your per-meal minimums — so you never guess again.

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Also try the Macro Calculator to set carb and fat targets alongside protein.

This calculator is for informational purposes only and does not constitute medical or nutritional advice. Individual needs vary. Always consult a qualified healthcare provider or registered dietitian before making significant changes to your diet.