You Are Not Your"self"

So far in Siddhartha, Siddhartha and Govinda have joined the Samanas, and are disconnecting themselves from the "self" by ignoring and purposefully depleting themselves of food and things necessary to life. Yeah okay. I don't really understand this at all. I don't get the difference between self and "self", and why you have to isolate yourself and eat as little as possible and avoid everything to be past the "self". however I can connect it to the ideas of Heidegger, who separated ever aspect of the human being frlmthe actual "being" itself, and that there are higher forms of being. And like Heidegger, you have to isolate yourself to achieve true being, or Nirvana. Does Siddhartha isolate himself in the same heideggerian way? It's not really clear, but I honestly dont think so, since siddhartha clearly appreciates people a lot more than heiddegger does.