Horrible Song. America does not need more "body positive" messages when most American bodies are in a very negative state. This is especially true for the African-American and Hispanic women who are largely the target of this song. Yes, you do need to worry about your size. No one's saying you have to be a stick figure silicone Barbie doll. But you don't have to be a hypertensive, diabetic blob either.
I basically second that, particularly because it comes from a Texan.
Aside from the part with the African American and Hispanic women; Southern white people (men + women) are overwhelmingly fat, too.