Major statistical fallacy. You can't take the average across a group and then assert that subgroups display the same average.
I don't have statistics for grad students (only personal observations), but I do have statistics showing that obesity goes up with poverty. For instance:
Sure, whatever. I guess it depends on the graduate program. Computer scientist PhDs are generally fat. Kinesiology grad students are usually fit. Everyone else is somewhere in between. I am not providing a link, because I don't care.
I don't have statistics for grad students (only personal observations), but I do have statistics showing that obesity goes up with poverty. For instance:
http://www.prb.org/articles/2010/usobesity.aspx