BodyCalThe daily number
The research here is unusually clear. To maximize muscle growth alongside resistance training, aim for roughly 1.6 to 2.2 grams of protein per kilogram of body weight per day. Studies find muscle protein synthesis is largely maxed out around 1.6 g/kg, with the higher end offering a little extra insurance, especially when dieting. For an 80 kg person, that's about 130 to 175 grams a day.
Going far beyond that range won't build extra muscle — the returns flatten out — though the extra protein can still help you feel full. Below it, you leave gains on the table no matter how hard you train.
Protein per meal matters too
It's not just your daily total — how you spread it counts. Muscle protein synthesis responds best to about 0.3 grams per kilogram per meal, which works out to roughly 20 to 40 grams for most people. Splitting your intake across three or four meals of that size beats loading most of it into one sitting.
There's a ceiling per meal, too: much beyond 40 grams and the extra is used for energy rather than driving more muscle growth. Even portions, evenly spaced, are the winning pattern.
The leucine trigger
The amino acid leucine is the switch that turns on muscle building. Each protein feeding needs roughly 2.5 to 3 grams of leucine to fully flip that switch — a threshold easily met by 20 to 40 grams of a quality protein like meat, fish, eggs, dairy, or whey.
Plant proteins tend to be lower in leucine, so if you eat mostly plant-based, slightly larger portions or a variety of sources helps you hit the threshold. This is the science behind why per-meal size matters, not just your daily total.
Timing and sources
The muscle-building response to a meal lasts only about three hours, so spacing protein every three to four hours keeps you topped up through the day. The old panic about a narrow post-workout window is overblown — hitting your daily total with even meals matters far more than rushing a shake the second you rack the weights.
Strong sources include chicken, lean beef, fish, eggs, Greek yoghurt, cottage cheese, tofu, tempeh, and legumes. A scoop of whey or plant protein is a convenient way to top up a meal that falls short.
Do you need supplements?
No. Protein powder is convenient, not magic — it's just a fast, cheap way to add 20 to 25 grams when whole food isn't handy. If you can hit your target from meals, you don't need it at all. Food first, powder to fill gaps.
Set your personal target with our protein calculator, then use the macro calculator to fit protein into your overall calories and build the rest of your day around it.