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Protein and Muscle Building: The Complete Scientific Guide (Dose, Timing, Sources)

Protein and Muscle Building: The Complete Scientific Guide (Dose, Timing, Sources)

What is the optimal protein dose for muscle building?

According to the International Society of Sports Nutrition (ISSN), optimal intake is 1.4 to 2.0 g of protein per kg of body weight per day, distributed in doses of 20-40g every 3-4 hours, with 700-3000mg of leucine per serving.

Calculate Your Protein Needs

120 - 150g protein per day
30-38g
per meal (4 meals)
2.1-2.6g
leucine/meal

Protein is the most studied nutrient in sports nutrition. Yet myths persist: "more is better", "you need to eat within 30 minutes post-training", "whey is essential". Here's what science actually says.

ISSN Official Position on Protein

Key ISSN Recommendations (Jรคger et al., 2017)

  • Daily intake: 1.4 to 2.0 g/kg/day for most athletes
  • In caloric deficit: up to 2.3-3.1 g/kg/day to preserve lean mass
  • Per serving: 0.25 g/kg or 20-40g of high-quality protein
  • Leucine: 700-3000 mg per serving to trigger protein synthesis
  • Distribution: spread intake every 3-4 hours

The Anabolic Threshold

The anabolic threshold is a minimum level of protein/essential amino acids needed to trigger muscle protein synthesis (MPS). This threshold varies by age and context:

  • Young adults: ~20g of high-quality protein is enough
  • Older adults: threshold increases (~40g needed)
  • Post-exercise: threshold decreases (muscle becomes more sensitive)

The Anabolic Window: Myth or Reality?

Contrary to popular belief, according to ISSN: the anabolic effect of exercise lasts at least 24 hours. There's no need to consume protein within 30 minutes post-workout.

Practical Applications

Optimized Protein Plan

  • On waking: 20-40g (after overnight fast)
  • Pre or post-workout: 20-40g with 2-3g leucine
  • Meals: distribute to reach 1.6-2.0 g/kg/day
  • Before bed: 30-40g casein or cottage cheese

๐Ÿฐ Calculate Your Protein Needs with Smart Rabbit

Our AI assistant analyzes your profile and calculates your optimal protein intake based on your goal and level.

Create My Smart Rabbit Program

โ“ Frequently Asked Questions

How many grams of protein per day to build muscle?

According to ISSN, 1.4 to 2.0 g/kg body weight per day is sufficient for most athletes. An 80kg man should consume 112-160g of protein daily.

Do you really need to eat protein within 30 minutes after training?

No, that's a myth. The anabolic effect of exercise lasts at least 24 hours according to ISSN. Exact timing matters less than total daily intake.

Is whey protein essential for muscle building?

No. Complete food proteins (meat, eggs, fish, dairy) are equally effective. Whey is simply convenient, not superior.

What is leucine and why is it important?

Leucine is an essential amino acid that triggers muscle protein synthesis. ISSN recommends 700-3000mg per protein serving to maximize the anabolic effect.

Can you consume too much protein?

Intakes up to 3.0 g/kg/day are considered safe for healthy individuals without kidney or liver issues. Beyond that, benefits are limited.

๐Ÿ‘จโ€๐Ÿ’ผ About the author

Jacques Chauvin

Fitness coach and founder of Smart Rabbit

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