On the list of the top 125 bodybuilding foods lentils and black beans are listed with protein amounts that are sky high. When I check the labels in the grocery store, the protein amounts are way lower.
I've heard that they have to be eaten in combination with rice in order to get the benefit of the protein.
I'm not sure why the protein totals would be different. Maybe the serving sizes are different? I've seen serving sizes that differ greatly from website to website. The bag of lentils I have in my closet say that there are 8g of protein in 1/4 cup dry (which is what the bag considers a serving.)
As far as the protein absorption goes, it used to be thought that you needed to get a complete protein at every meal to get the benefit. Since beans are an incomplete source of protein (doesn't contain all essential aminos) you would need to combine them with a grain (like rice) to make it complete. Nutritionists are now saying that this is not necessary as long as you eat various sources of protein throughout the day. It sounds like you are body building though, so it may be different for you. I'm not sure.
Those two entries have got to be erroneous . . . black beans and lentils are touted as being a couple of the very best legumes to eat . . . but they really are not vastly different from Chickpeas or Kidney Beans. I'd believe the can/package details if I were you.
Yeah, I think the last numbers in the calorie row were moved into the protein row by mistake. If you moved them over it would read black beans 114 cal/8g protein and lentils 115 cal/9g protein. I just made black bean refried beans tonight and that sounds right.