Articles about this topic.
Almonds and pistachios lead the tree-nut ranking, but the number that matters in your hand is smaller: a 1-ounce serving gives roughly 6 grams of protein, not the 20-plus grams suggested by a 100-gram table.
Hemp and pumpkin seeds can nearly match chicken breast for protein when everything is compared per 100 grams. The difference shows up on the plate: seed servings are usually around an ounce and provide roughly 5–9 grams.
Yes, vegetables contain protein, but even the standouts usually provide only about 3–4 grams per 100 grams. The useful question is not whether broccoli can imitate chicken, but how much protein it actually adds to a plate.
Lean cooked meats are closer together than most protein rankings make them look: most fall around 27–33 g per 100 g. Cut and cooking water loss can matter as much as the animal itself.
Cooked yellowfin tuna leads clearly at about 29 g of protein per 100 g. Most of the other fish here fall between roughly 20 and 24 g, so calories, omega-3 fat and, for certain species and groups, mercury often matter more than a one-gram protein difference.
Parmesan dominates per 100 grams because it is so concentrated, but most people do not eat it in the same portion as a fresh cheese. Once serving size enters the picture, the ranking tells a different story.
The ranking changes when the question shifts from 'how much protein is in 100 grams?' to 'how much protein do I get for 100 calories?' Lean fish, egg whites, turkey and chicken suddenly move toward the top.
Soybeans and lupini beans clearly separate themselves when cooked legumes are compared fairly. Lentils, chickpeas and common beans, on the other hand, are close enough that chasing tenths of a gram is not very useful.
Chia and flax lead on fiber per 100 grams, while a full serving of beans or lentils can contribute more total fiber than a spoonful of seeds.
Tempeh, tofu, seitan, soybeans and legumes are easy to use as the protein center of a plant-based meal. Nuts and seeds add protein, but their usual servings are smaller.