I agree that a low carbohydrate diet makes depression worse, a low-GI diet is supposed to be good and it helps blood sugar levels remain stable.
I have read (somewhere) that eating a banana before going to bed is good for depressed people - have actually read this in a few websites and books. I have just read rowan/redman's post - tryptophan - that is what bananas have.
I have a friend who is Bipolar and takes lots and lots of exercise - he says that it has made a positive impact on his health.
If lucky a person may just have one episode of depression - for some it recurs. Being Bipolar is usually a lifetime illness, but a person will not be ill all the time.
The Bipolar Fellowship is a support organisation that has many helpful leaflets that can explain all the complexities of the disorder.
Susan