It is my understanding (correct me if wrong) that body is related to mouth feel, which to a large degree is created by the mashing temperature. Sounds like you mashed quite low, made lots of fermentable sugars, and thus the low FG. Your beer is probably rather dry too, I bet.
"Beer, well respected and rightly consumed, can be a gift of God. It is one of his mysteries, which it was his delight to conceal and the glory of kings to search out."
The Search for God and Guinness by Stephen Mansfield