Does diet affect hairballs?

My cat has just turned 2 years old. Recently, she has been having a lot of hairball issues. She hacks one up every couple of days and coughs and wheezes a lot of the time. She is somewhat overweight so I have to be careful what I feed her and how much so I switched her from Natural Balance to Chicken Soup light. Since then her hairball issue has gotten progressively worse. I put that greasy stuff in her wet food that is supposed to help. I think it is called laxatone or something like that. I also grew some grass in a little container and give her hairball control treats. She hates the treats though. She is shorthair and kind of independent so its hard to brush her but I can do it if she's hungry. Just wondering if anyone has any tips for this problem.