Let me add to the discussion by saying that caste has never been proved by scientific evidence (at least not the kind of microscope-and-formulas that passes for science these days), but by the direct observation of human nature that anyone unprejudiced and with a healthy judgement can do. You don't need a bunch of statistics to prove everything under the sun.
In my view, the only "poor" that are toxic to society are those that are unable to stand on their own, and are constantly needful of the aid of others (people, organizations, capacitation programs, banks) in order to get on with their lives. To judge it by income is very relative. I bet most people here are either unemployed or at the struggling stage of their lives. I am of the second group, and if solely considered by income then I'm poor by my country's standards, and much more so by those of any first world country. And yet I can stand very well on my own two feet because I have needs that are easy and cheap to satisfy, I'm not a frivolous fool, and I save all the money I can, so that at the end of the month I'm always with cash in my pocket.
As for nutrition, I don't presume to be an expert on the subject, but I have designed my own diet based on my needs, and I have been doing quite well with it. And I buy my food, just like anyone else. The thing about healthy nutrition is that it takes a fair amount of will to persist in it and deny to oneself many foods that are tempting but won't do much good. And this the people don't want to know about, because most have no will, except to do what's absolutely necessary to sustain themselves, their families, and buy the crap that momentarily fills the void in their hearts.