I was just wondering if beans like black beans or pinto beans are a vegetable. I had always thought they were a protein. But, maybe they're a combination of the two?
It is difficult to find foods which are purely protein and nothing else. Sure, egg whites are 100% protein, and tinned tuna is about 95% protein (this is looking at what percentage of their calories come from protein) but most foods are a combination of fat, carbs and protein.
Lean meat, fish, egg whites, soft cheeses often derive more than 50% of their calories from protein - so they are significant sources.
Plant foods can be sub-divided into 4 categories: vegetables, fruit, legumes (also known as pulses) and grain (also known as cereal). Most are mostly carbohydrates.
Some plant foods (Spinach, Mushrooms, Broccoli all spring to mind) derive more than 50% of their calories from protein - but most plant food does not come this high. Pinto Beans are a type of legume. Legumes generally have 20%-30% of their calories coming from protein.
The figures I have for Pinto Beans: 100g (cooked) provides 137 calories and 8.9g of protein - so that's 26% of calories coming from protein (70% from carbs, 4% from fat).
So Pinto Beans primarily provide carbohydrates, but with 26% of their calories from protein, that is a higher proportion than many vegetables, most fruit, all grain, all nuts and seeds (including peanut butter :)). Pretty much the only things that beat them at the protein stakes are those higher-protein vegetables (like broccoli), some products derived from soy bean, and those animal protein foods mentioned above.
