Have you read Marya Hornbacher's memoirs? She wrote her first one - "Wasted" - about her very severe eating disorder(s), and then years later wrote her second one - "Madness" - after she was diagnosed with BP. At the time she wrote Wasted (young, like 23 y.o) she didn't know she had bipolar. In Madness she talks about how she came to understand that her eating disorder was a desperate attempt to gain control over her moods.

restricting food could be messing with your moods, making you hypomanic (and thus less anxious as well). i'm sure you are aware that this is not a healthy or sustainable solution tho...