Protein Intake for Strength Athletes: What the Research Actually Says

The short answer

If you lift weights regularly and you want to build or preserve muscle, eat between 1.6 and 2.2 grams of protein per kilogram of body weight per day. Spread across 3 to 5 meals. That is almost all of what the evidence actually supports.

Everything else, timing, source, pulses vs continuous, is a rounding error on top of hitting that daily number consistently.

Where the number comes from

The most frequently cited meta-analysis is Morton et al. (2018), which aggregated 49 studies and found that muscle protein synthesis gains plateau around 1.62 g/kg/day for strength-trained individuals. Higher intakes, up to roughly 2.2 g/kg, show marginal benefits but also no harm in healthy populations. Beyond 2.2 g/kg, the ceiling is firm.

For a 75 kg lifter, that is roughly 120 to 165 g of protein per day. For a 90 kg lifter, 145 to 200 g.

How to hit it without tracking every meal

You do not need to log every gram. You need to anchor each meal with a protein source.

• Breakfast: 30-40 g (3 eggs plus a yoghurt, or a protein smoothie)
• Lunch: 40-50 g (150 g chicken breast, or a tuna can plus cottage cheese)
• Post-workout snack: 20-30 g (whey shake, or Greek yoghurt)
• Dinner: 40-50 g (steak, salmon, or a generous serve of beans plus dairy for plant eaters)

That gets most lifters into the 130-170 g range without a food scale. For heavier athletes, add a late snack: cottage cheese, tinned fish, or a casein shake before bed.

What actually moves the needle

1. Consistency first. Hitting your target five days out of seven beats hitting it seven days when you feel like it.
2. Enough per meal. Below 20 g per meal, the leucine threshold for muscle protein synthesis often is not crossed. Three small snacks of 15 g each is worse than three meals of 30 g.
3. Fuel training sessions. A meal or shake 1-3 hours before training makes the session easier and puts amino acids in circulation during the lift.
4. Post-workout is overhyped but not useless. If you finish training and go five hours without eating, you are leaving adaptation on the table. Within two hours is ample.

What does not matter

• Specific brands of whey
• Casein vs whey timing micro-optimisation
• Grams per meal measured to the nearest five
• Fasting windows beyond 14-16 hours (for most lifters)

Protein and your training data

Pelaris is a training app, not a nutrition app. That is a conscious scope decision, we do not prescribe calories or macros, because nutrition coaching has its own failure modes and we do not want to stretch the AI beyond where we have real evidence it helps.

What we do is watch your training data and flag when recovery is slipping. The workout tracker captures RPE on every set, session volume per week, and readiness check-ins. When RPE climbs across consecutive weeks on the same loads, or sleep quality drops, or soreness stops resolving, the coach surfaces it and adjusts the next week’s training accordingly. Under-fuelling, low protein in particular, is one of the usual suspects behind that signal.

If you are serious about strength training or CrossFit programming, protein is the single nutritional lever with the clearest research support. The rest of nutrition science is noisier. Hit 1.6 to 2.2 g/kg consistently, spread across 3-5 meals, and you remove one variable from the program response. Everything else can iterate on top of that foundation.

For the training-side inputs that actually live in the product, see the methodology library and the engine-style guides covering recover, learn, and prepare alongside this fuel category.