If you take a look at the text of the eighth grade portion, Alexie's character was noticing girls at the "white school" he now attended worked so hard to keep skinny that they would starve themselves on purpose by being aneorexic. This intentional starving was for the purpose of looking skinny, not a healthy decision.
Then he commented on the Indian way of life on the reservation. He reported on the disgusting food choices offered. They had to stand in great lines to get their ration of really gross canned beef. Although they ate it, they felt sorry for themselves having to eat it.
Whereas the girls struggled with their self-image in terms of beauty, the young Indian boy struggled with his self-image in terms of identity within society, both among Native Americans and teens in normal junior high and high school settings. Both of these groups robbed themselves, starved themselves of truly living life to the fullest.
If you look at the end of each grade, Alexie reveals a truth about Native Americans for both the Native American and the other American to think about. I think this one here is insinuating that we all have struggles, we all have problems. That's where he gets the "There's more than one way" portion of the statement.