Protein Intake Calculator

The RDA of 0.8 g/kg per day is the amount that prevents deficiency in a sedentary person. It was never meant as a target for people who train. For anyone active, the sports nutrition literature points higher: roughly 1.2 to 1.6 g/kg for general training, and 1.6 to 2.2 g/kg when the goal is building muscle. That upper figure comes from a 2018 meta-analysis by Morton and colleagues covering 49 resistance-training trials, which found gains plateau around 1.6 g/kg on average with an upper confidence limit near 2.2 g/kg.

Fat loss changes the math. In a deficit, higher protein (1.8 to 2.7 g/kg) helps hold onto muscle while the scale drops, and reviews of lean, trained dieters support the top of that range during aggressive cuts. Older adults get their own adjustment: after about age 65, muscle responds less to each meal (researchers call it anabolic resistance), so 1.2 g/kg or more is the sensible floor even for someone mostly sedentary.

Worked example: a 180 lb (81.6 kg) lifter trying to build muscle lands at 1.6 to 2.2 g/kg, which works out to about 131 to 180 grams per day. Split over four meals, that is 33 to 45 grams per meal: a chicken breast and a glass of milk, or a cup of Greek yogurt with a scoop of whey.

First, muscle retention. When calories drop, your body will happily burn muscle along with fat unless you give it a reason not to. High protein plus resistance training is that reason, and it is the difference between ending a diet lean versus just smaller.

Second, satiety. Protein is the most filling macronutrient per calorie, which makes a deficit easier to sustain. Third, the thermic effect: digesting protein burns 20 to 30 percent of its own calories, versus roughly 5 to 10 percent for carbs and 0 to 3 percent for fat. None of these effects is huge alone, but over months of dieting they add up.

The old advice said you had 30 minutes after training to slam a shake or waste the workout. Current research puts the realistic window at more like 4 to 6 hours around a session, and if you ate protein in the hours before lifting, you are already covered.

The related myth says the body can only absorb 30 grams per meal. Absorption is nearly complete no matter the dose; what levels off is the per-meal muscle-building response. That is a fair argument for spreading protein across 3 to 5 meals of about 0.4 g/kg each, and it is exactly what the per-meal split above gives you. It is not an argument that a 60-gram dinner is half wasted. It all counts.

Plant proteins like tofu and lentils work fine for building muscle. They tend to be a little lower in leucine per gram, so vegetarians and vegans usually do best aiming at the higher end of their range and mixing sources across the day.