Quick Answer: Protein recommendations are expressed per unit of body weight, but the actual driver is lean mass and training stimulus. Two people at the same weight with different body compositions and different training loads have genuinely different requirements, which is why a fixed gram target works well for one and poorly for the other.

Your friend hit 120 grams a day and felt transformed. You hit 120 grams a day and felt nothing in particular. Neither of you did anything wrong.

Why is per-body-weight the standard if it’s imprecise?

Because it’s simple and reasonably accurate across a typical population. Body weight correlates with lean mass well enough for general guidance, and most people don’t know their body composition.

The imprecision shows up at the edges. At higher body fat percentages, total body weight overestimates the tissue actually driving protein requirements, which is why guidance for that situation often shifts to using lean body mass or an adjusted body weight instead. It’s not that the standard is wrong — it’s that it’s a population average being applied to an individual.

What ranges are actually supported?

For general health, commonly cited intakes sit around 0.8 g/kg of body weight as a minimum to prevent deficiency — a floor, not an optimum.

For people training regularly, research on muscle protein synthesis and body composition generally supports a range around 1.6-2.2 g/kg, with limited additional benefit above roughly 2.2. For someone in a calorie deficit trying to preserve muscle, the upper part of that range tends to be more protective, since protein needs rise rather than fall when energy is restricted.

Does distribution across the day matter as much as total?

Less than total, but not nothing. Total daily intake is the dominant factor for body composition outcomes. Distribution appears to offer a modest additional benefit.

The commonly cited approach is roughly 20-40g of protein per meal across three to four meals, which keeps muscle protein synthesis stimulated multiple times a day rather than once. If your total is already on target, redistributing is a refinement worth maybe a few percent — worth doing, not worth stressing about.

Myth vs Fact: Protein

Myth: Extra protein converts directly to muscle. Fact: Protein supplies material; training supplies the signal. Without the training stimulus, additional protein above requirements is largely used for energy or other processes.

Myth: High protein damages healthy kidneys. Fact: In people with normal kidney function, higher protein intakes within these ranges have not been shown to cause kidney damage. This is a genuinely different question for people with existing kidney disease, who need individual medical guidance.

Myth: You can only absorb about 30g at a time. Fact: Absorption isn’t the limiter — you absorb essentially all of it. What plateaus is the muscle-building signal per meal, which is a different mechanism and a much softer ceiling.

Myth: Plant protein can’t support the same outcomes. Fact: It can, but total intake usually needs to be somewhat higher and variety matters more, since individual plant sources have different amino acid profiles and lower leucine content.

How do you figure out your own number?

Start from the range rather than a single figure, and adjust from feedback.

A practical process: estimate 1.6 g/kg of body weight if you train regularly, track actual intake for one week (most people substantially overestimate), then adjust based on recovery quality, hunger, and whether strength is progressing. If you’re in a deficit, move toward the upper end.

If body fat is high, using an adjusted figure — often somewhere between current weight and a goal weight — gives a more realistic target than raw body weight. And if the number seems impossibly high, that’s usually a signal to check the tracking week before changing the target.

FAQ: Protein Target Questions, Answered

Do I need protein immediately after training?

The anabolic window is far wider than the old 30-minute framing suggested. Total daily intake matters much more than timing around a session.

Is a supplement necessary?

No — powder is a convenience for hitting a target, not a category of nutrition food can’t provide. It’s useful if food alone isn’t getting you there.

Does protein need change with age?

Evidence suggests older adults benefit from intakes at the higher end of the range to counter age-related anabolic resistance, alongside resistance training.

TL;DR:

• Per-body-weight targets are population averages, not individual prescriptions
• Lean mass and training load are the actual drivers of requirement
• Around 1.6-2.2 g/kg covers most people who train; higher end during a deficit
• Total daily intake matters far more than timing or distribution
• Track one honest week before changing your target

This is general information, not medical advice — protein needs differ meaningfully with kidney conditions, pregnancy, and other medical situations, which are conversations for your own provider.