How Much Protein Do You Actually Need Per Day?
Protein advice is unusually confused. The official recommendation says one thing, gym culture says another, and the gap between them is wide enough to be genuinely confusing.
Both are right — they are just answering different questions.
The RDA is a floor, not a goal
The Recommended Dietary Allowance is 0.8 grams of protein per kilogram of body weight. That figure answers a specific question: how little protein can a sedentary adult eat without developing a deficiency?
It is a minimum to prevent harm. It was never intended as the optimal intake for someone lifting weights, running, dieting, or trying to hold onto muscle into their sixties.
What the research supports
Broadly, four tiers cover most people:
- 0.8 g/kg — sedentary adults, the deficiency floor
- 1.2 g/kg — active adults, and older adults generally
- 1.6 g/kg — building muscle alongside resistance training
- 2.0–2.2 g/kg — losing fat while training, to preserve muscle
The last tier surprises people. Protein needs go up when you are dieting, not down. In a calorie deficit your body is looking for tissue to break down, and adequate protein plus resistance training is what steers that toward fat rather than muscle.
A worked example
Someone weighing 160 lb — about 72.6 kg — aiming to build muscle at 1.6 g/kg needs roughly 116 grams of protein a day.
Spread across four meals, that is about 29 grams per meal. In practical terms, one of the following at each meal gets you there:
- A chicken breast
- A large tub of Greek yoghurt
- Two eggs plus a glass of milk
- A scoop and a half of whey protein
- A block of tofu with a side of lentils
Framed that way, 116 grams stops looking like an athlete's diet and starts looking like ordinary meals with a protein source deliberately included.
The absorption myth
You will often hear that the body can only absorb 20–30 grams of protein in one sitting, and the rest is wasted.
This confuses two different things. You absorb essentially all the protein you eat. The 20–30 gram figure refers to the amount that maximally stimulates muscle protein synthesis in a single meal, which is not the same as absorption.
Spreading protein across meals does appear marginally better for muscle building, which is why a per-meal target is a useful planning tool. But the daily total is what matters most. If your schedule means two large protein meals instead of four moderate ones, you are fine.
Can you eat too much?
For people with healthy kidneys, intakes well above these targets have not been shown to cause harm in the research literature. The concern about protein damaging kidneys comes from studies of people who already had kidney disease.
The real limits are practical. Protein is filling, which is usually an advantage when dieting but makes very high intakes genuinely hard to eat. It is often the most expensive macronutrient. And calories spent on excess protein are calories not available for carbohydrate to fuel training or fat to support hormone production.
Should you use total weight or lean mass?
Total body weight works for most people and is what these targets are built on.
If you carry a significant amount of excess body fat, calculating from lean body mass or a realistic goal weight avoids an unnecessarily high number. Fat tissue does not require protein to maintain, so scaling the target to it just makes the goal harder than it needs to be.
The simplest way to get there
Put a protein source in every meal, first, and build the rest of the plate around it. Most people who fall short do so because protein is an afterthought at breakfast and lunch, leaving an impossible gap to close at dinner.
Work out your own daily and per-meal target with the Protein Calculator.