🌱 Plant vs Animal Protein: Amino Acid Profile, PDCAAS and mTOR
How protein sources differ and how to combine them
Protein is a key macronutrient for muscle, immunity and tissues. Plant and animal sources differ in amino acid profile, digestibility (PDCAAS) and effect on mTOR — the cell growth pathway. We break down the differences.
What is protein
Protein consists of amino acids, including 9 essential ones that the body does not synthesise. It is important for muscle mass, immunity, enzymes and hormones. Protein quality depends on amino acid composition and digestibility.
- Consists of amino acids.
- 9 essential amino acids.
- Important for muscles and immunity.
- Quality depends on composition.
Amino acid profile
Animal protein usually contains a complete set of essential amino acids in the right proportions. Plant protein is often limited in one or more amino acids (e.g. lysine in grains, methionine in legumes), but they can be combined.
| Source | Profile | Comment |
|---|---|---|
| Animal | Complete | All essential |
| Soy | Complete | Plant exception |
| Grains | Limited | Low lysine |
| Legumes | Limited | Low methionine |
PDCAAS index
PDCAAS (protein digestibility-corrected amino acid score) is a protein quality indicator from 0 to 1. Animal protein usually scores 1.0, soy about 0.9–1.0, grains lower. The closer to 1, the better the digestibility.
| Source | PDCAAS | Comment |
|---|---|---|
| Egg | 1.0 | Reference |
| Soy | 0.9–1.0 | Best plant |
| Pea | ~0.7 | Good |
| Wheat | ~0.4–0.5 | Lower |
Effect on mTOR
mTOR is a pathway that stimulates muscle and cell growth. Protein, especially rich in leucine, activates mTOR. Plant protein often contains less leucine than animal protein, affecting the anabolic response.
- mTOR stimulates muscle growth.
- Leucine activates mTOR.
- Animal protein is richer in leucine.
- Plant — lower anabolic response.
Food: sources
| Food | Protein | Type | Comment |
|---|---|---|---|
| Chicken breast | ~25 g/100 g | Animal | Complete |
| Eggs | ~13 g/100 g | Animal | Reference |
| Soy/tofu | ~8–15 g/100 g | Plant | Complete |
| Lentils | ~9 g/100 g | Plant | Legumes |
| Buckwheat | ~13 g/100 g | Plant | Grains |
How much to eat
- Norm 1.6 g/kg (sport): ~100 g chicken + eggs + legumes.
- For vegetarians: soy + legumes + grains + nuts.
- Combine grains and legumes for a complete profile.
Norms
| Indicator | Value | Comment |
|---|---|---|
| Minimum norm | 0.8 g/kg | Sedentary |
| Activity | 1.2–1.6 g/kg | Training |
| Muscle gain | 1.6–2.2 g/kg | Sport |
Practice
- Combine animal and plant sources.
- Include soy for a complete profile.
- Add legumes and grains together.
- For muscle gain, watch leucine.
- Distribute protein across meals.
How does plant protein differ from animal?
Animal is complete; plant is often limited but can be combined.
What is PDCAAS?
A protein quality indicator (0–1) accounting for amino acids and digestibility.
Which plant protein is most complete?
Soy (tofu, soy protein) is the most complete plant source.
How does protein affect mTOR?
Protein, especially with leucine, activates mTOR — the muscle growth pathway.
How much protein is needed?
0.8 g/kg minimum, 1.2–1.6 g/kg with activity, up to 2.2 g/kg in sport.
Can protein be gained on veganism?
Yes, by combining soy, legumes, grains, nuts and seeds.
Which foods have a lot of protein?
Chicken, eggs, soy, lentils, buckwheat, fish.
What are essential amino acids?
9 amino acids that the body does not synthesise and must get from food.
Is it necessary to combine grains and legumes?
Yes, it gives a complete amino acid profile.
Which protein is better for muscle?
Animal is richer in leucine, but combining sources also works.