Sister relies on junk food to battle depression (family issues)?

I was once depressed a lot, cutting, but it wasn't that serious. What I tried doing was looking at the good part of life. Making the best of everything. Thinking positive. Try telling you're sister this and also that life wouldn't be the same without her. Let her know how important and wanted she is. Take a walk with her outside, make healthy meals for her. Help her get active. Sign up for some sort of sporting events.