How Much Protein Is in Plant-Based Foods?
Protein in chia seeds, edamame, and peanut butter - including amino acid quality, bioavailability, and how to combine plant proteins.
Plant-based protein sources can be an excellent part of any diet - whether you are vegan, vegetarian, or simply want more variety. But not all plant proteins are equal. Here is what you need to know about three popular options: chia seeds, edamame, and peanut butter.
All nutrition data is from the USDA FoodData Central database.
Protein in Chia Seeds
| Measure | Protein | Calories |
|---|---|---|
| Per 100g | 17g | 486 |
| Per 2 tablespoons (28g) | 4.7g | 136 |
Chia seeds are relatively high in protein by weight, but a typical serving is small (1–2 tablespoons). They also provide omega-3 fatty acids, fibre (11g per ounce), and minerals like calcium and magnesium.
Amino acid note: Chia seeds are low in lysine, which means they are not a complete protein on their own. Combine them with lysine-rich foods like legumes or dairy for a complete amino acid profile.
Protein in Edamame
| Measure | Protein | Calories |
|---|---|---|
| Per 100g (shelled, cooked) | 11g | 121 |
| Per cup (155g) | 17g | 188 |
Edamame (young soybeans) is one of the best plant-based protein sources available. Unlike most plant proteins, soy is a complete protein - it contains all nine essential amino acids in adequate amounts. Soy scores 0.91 on the PDCAAS scale, nearly matching animal proteins.
A cup of edamame delivers 17g of protein - comparable to 2.5 eggs.
Protein in Peanut Butter
| Measure | Protein | Calories |
|---|---|---|
| Per 100g | 25g | 588 |
| Per 2 tablespoons (32g) | 8g | 188 |
Peanut butter packs a solid 8g of protein per serving, but it is also calorie-dense. If you are tracking both protein and calories, keep portions in check.
Amino acid note: Peanuts are low in methionine. Pairing peanut butter with whole grains (toast, oats) creates a complementary amino acid profile.
Plant Protein Quality: PDCAAS Scores
The Protein Digestibility Corrected Amino Acid Score (PDCAAS) measures protein quality on a 0–1 scale:
Soy stands out as the highest-quality plant protein. Other plant sources benefit from combining with complementary foods (grains + legumes, seeds + dairy).
Other Notable Plant Protein Sources
| Food | Protein per 100g |
|---|---|
| Tempeh | 19g |
| Tofu (firm) | 8g |
| Lentils (cooked) | 9g |
| Chickpeas (cooked) | 9g |
| Black beans (cooked) | 9g |
| Quinoa (cooked) | 4.4g |
| Chia seeds | 17g |
Can You Build Muscle on Plant Protein?
Yes. A 2021 meta-analysis published in Sports Medicine (Hevia-Larraín et al., 2021) found that plant-based protein supplementation produced equivalent muscle gains to animal protein when total protein intake was matched. The key is eating enough total protein - aim for the same 0.7–1.0g/lb (1.6–2.2g/kg) per day range recommended for muscle growth.
Tips for Maximising Plant Protein
- Eat soy regularly - edamame, tofu, and tempeh are the highest-quality plant proteins.
- Combine sources - grains + legumes, nut butter + bread, seeds + yogurt.
- Consider a plant-based protein powder (pea, soy, or rice blend) if you struggle to hit your target from food alone.
- Track your intake - use Protein Pal to ensure you are reaching your daily goal, especially if your diet is entirely plant-based.
The Bottom Line
Chia seeds, edamame, and peanut butter each bring meaningful protein to the table - with edamame leading as a complete protein source. Plant proteins can absolutely support muscle growth and overall health when total intake is sufficient and sources are varied.