Here’s what I know: on average, eating lots and lots of vegetables (7-9 servings a day) and little to no processed food or junk food, is associated with reduced rates of depression.
Here’s what I don’t know: whether this would help in your case.
It couldn’t hurt though. That’s for sure.
I would recommend trying no sugar (no sweeteners of any kind), no flour, and very large amounts of vegetables.
After you are more comfortable in the Bright Line Eating way of living, you can incorporate exercise to lift depression.
These are just my musings. I’m not a doctor, but I did suffer with depression on and off for much of my life (from the age of 10 until I changed my diet at the age of 28), and eating this way definitely helped me. I’m not sure whether our cases are similar enough for it to offer real hope, but again, it couldn’t hurt.