I'm vegetarian. Meat, fish and eggs increase my fatigue. I've cut out a lot of gluten in my diet and it's helped my fatigue as well. Anything with high fructose corn syrup sends me into a flare. I stay away from pop/soda, in fact the only thing I drink is water and herbal tea and from time to time freshly squeezed orange juice.
I've heard about nightshades causing problems but haven't noticed any difference with me. I try to drink half my body weight in water to flush out toxins. Sometimes I succeed, most of the time I don't. As for vitamins and minerals, I'm currently taking Flax Seed Oil and it's helping with my PMS.
As for sweets, I'm diabetic so I have to watch that. I stay away from mainstream sweets like twinkies, and pies. If you can get it in the regular grocery aisle, I don't eat it. If it has high fructose corn syrup in it, I don't eat it. I try to eat only 100% natural dark chocolate. My sister and I had some gluten-free cookies last week and they were good. It came in a box (gluten-free cookie mix) and we added all natural peanut butter to it.
The Kroger that we go to has a natural foods section. That's basically the only section I visit in the store besides the produce section. They have a nice variety of dark chocolate, antioxidant bars, cookies and chips.