I was a neurology professor at a children's hospital in my previous job, and there is a ton of research being done studying the neurological effects of a low-carb diet, and they are, across the board, incredible. A common treatment for kids with epilepsy is the keto diet, so we had a lot of research and expertise in this area. Half of the department was on the diet, and I have been for close to two years now. I will never stop it. My wife and kids as well (though the kids are more paleo, since they have closer to 75-100 g carbs/day)
i was in bed with a rage-depression ten times worse than a normal bout. i couldn't work for three days. i can't describe my thoughts because they are still so embarrassing. on the forth day, i figured out, well, the whole time i was depressed i thought the 'trigger' was a text from a friend. i re-read the text. it didn't even say what i thought it said.
the next day i had another coffee followed immediately by a panic attack. then i put it together and tossed the coffee. i stopped all caffeine, which for me meant no chocolate, for two weeks. i was dieing for some chocolate. so i had some with the kids on a sunday. two days later i was depressed and on a very short fuse.
now i've gone about two months with no chocolate. i sleep much better. i don't snap at people. i don't get angry. in a sense, i miss the highs very much but not enough to want to go back. i've just accepted that my brain doesn't react to caffeine like most people.
When I dropped caffeine and alcohol my anxiety went away. When I exercised my depression went away.
I tried a lot of things, but it ended up figuring out that I wasn't eating well or working out.
Now I do crossfit. I know, I know. It's a cult blah blah. But go try it. You need to be exercising every day to get all that endorphin goodness and plus, you meet a lot of fun people at crossfit. The community keeps me coming back. I don't get that biking (which I love) so I don't do it as much as crossfit. And I hate running. The key is to keep doing it, and that social component works magic. If you can work out at a home gym every day - good for you - but I lose interest and stop, then I get fat and lazy and depressed again.
As for food, I'm not a fan of cooking. But I found paleo then keto. And I avoid all the stuff you're told to eat. "healthy" grains, for example. I don't drink coke. Basically avoid all sugar. I'm basically paleo to paleo-keto end of the spectrum.
I really didn't think it would work but there it is.