How long would you have to eat like an anarexic to become infertile?

I know it sounds like a stupid idea put its the only thing I can think of. I have been pregnant once about two years ago and currently all an accident. And I am allergic to birth control. I don't like the idea of getting my tubes tied because everyone I know who did it got tumors and one got two tubal pregnancies. Besides that in Arkansas women under 30 I think have to have three kids or more before doctors will do it. And im determined for there NOT to be a third. So after this baby is born I seriously am just thinking about eating like an anarexic. I just don't know how long till it would cause infertility. This is what I want I don't want more than two kids and I am not good with kids. I don't trust myself to have a whole bunch of kids.