Hi Mimi
Every morning when I wake I say to God - I am powerless over alcohol and food when I take my Step 1.
I am a recovered alcoholic and compulsive overeater and I am equally as powerless over both - because food always leads me to pick up alcohol and vice versa.
While it is not necessary that you go to OA to recover from your food addiction - you can work the steps in AA, just adding food into the first part of step 1 but it is a good idea to work with a sponsor who understands food addictions and eating disorders. With alcohol, abstinence is not drinking. With food it is far more individual to the addict.
Also as you work through the steps, to maintain your recovery from your food problems as well as alcohol, it would be a good idea to work with others who have the same problem.
All the addict is doing with multi addictions is using substances to fill a void within them and try to make themselves feel better. Whatever your addiction though, the cause is the same spiritual malady which needs the same spiritual solution.