The study is about grams of protein in a supplement, not grams of food eaten.
This is the same thing as “What heavier: 1kg of steel or 1kg of wool?”
Also, you don’t need to eat 1000g of plants to get 21g of protein.
Peanuts have 26 grams of protein per 100g, that’s more than your example of chicken.
Black pepper is about 10% protein by weight. So, if you want to be gross, that’s about 210g of black pepper.
The study is about grams of protein in a supplement, not grams of food eaten. This is the same thing as “What heavier: 1kg of steel or 1kg of wool?”
Also, you don’t need to eat 1000g of plants to get 21g of protein.
Peanuts have 26 grams of protein per 100g, that’s more than your example of chicken.
Black pepper is about 10% protein by weight. So, if you want to be gross, that’s about 210g of black pepper.
26g of protein sure, but also 570 calories. Lean meats are hard to compete with, especially on a cut.