My recommendation would be to approach it as you approached your drinking, which is also an addiction that you have been successful in dealing with. You realized drinking was a problem, you made a decision to quit, you made a plan and found resources to help ( SR, AA, counseling ), and then you followed through on the plan every day. Certainly there are rough patches but indeed you have quit drinking and stayed quit for quite some time.
About the only thing that might be a little different is the resources you use - maybe you need to see a counselor that specializes in eating disorders, or a nutritionist. But overall it's the exact same steps. You've already completed the first two in recognizing the problem and seeking help.