The only thing that works at all for me is regular exercise (30-60 minutes with an elevated heart rate 3-6 times per week) and a stupidly strict ketogenic diet - fats, moderate meats (including eggs, red meat, poultry and seafood), limited seeds and nuts, and tons of low glycemic index vegetables and fruits (mainly above ground veggies, stone fruit, berries). Limited dairy. No beans or grains. No alcohol. Nothing processed. No sweeteners.
But when I do that for a while (weeks), I feel amazingly better. My head is clear. I have energy. I’m not nauseous or dizzy. I still get break thru symptoms and some weeks are better than others, but the average is much higher. It’s like going from the basement to the second floor.
Also, I stop gaining weight. Sometimes I lose some.
My best run on this diet is 6 months. I’m currently working on matching or beating it but am back in early days.
You also have to give yourself a cheat meal every once in a while. You might feel crappy afterwards but it keeps you from feeling deprived and quitting.