Quote Originally Posted by agnesamurphy View Post
Okay, a 6-ounce broiled porterhouse steak has about 40 grams worth of protein, which is much more than the 18 grams a cup of cooked lentils. Source: http://www.hsph.harvard.edu/nutritionsource/protein/

If "good protein source" is simply based on how many grams of protein is has, then the steak wins. If it's based on percentage of calories from proteins, then the steak wins too.

However, the steak has saturated fat. The lentils don't. Beans are also an excellent source of fiber, copper, phosphorus, manganese and magnesium. The steak doesn't have any of those things. One might need more beans to fulfill the daily requirement of protein, but one is also getting a lot of other things s/he do need and none of the saturated fat s/he doesn't need. This blows the macronutrient argument out of the water.

And how does the fact that you need to eat beans with other things make them a bad source of protein? Who just eats plain beans and nothing else with them, or just beans for an entire day? No one eats a steak or a chicken all by itself, so why does that count against the plant sources of protein and not against the meat sources?

It seems that it comes down to the fact that we differ in our definitions of "good sources of protein" and "too much protein."
note how you had originally said beans and nuts were good sources of protein, I singled out nuts for an obvious reason, then you went on to breakdown beans/lentils instead

http://nutritiondata.self.com/facts/...roducts/3138/2

walnuts, good source of monounsaturated fats, omega 3 fats (albeit ALA and not the preferred EPA/DHA), lot of good micronutrition, but <10% protein by calories.

The reason I had originally pointed this out is quite literally I know a lot of people, typically females, who think that having some nuts or peanut butter is all the protein they need for a meal and might be one of the highest protein containing foods they eat on a regular basis. Which brings me to another point, a lot of people in general don't know what any of the numbers on a nutrition label mean let alone how to read an ingredient list.