This. In my country we don't have fluoride in water, but we do have toothpaste with fluoride. I noticed a significant difference in a several days after I stopped using fluoride toothpaste. I'd imagine having it in water as well won't do any good.
For the food, I've been working at swapping out everything that has additives in it. The theory is, our brain tells us what we need by giving us a "craving" for a specific taste. If you can find something natural that satisfies that craving, (fruit instead of candy, etc) you will probably feel better. At least that works for me. You need to give most of the natural stuff a shot first though, if you never eat it your brain doesn't know what to tell you.
Craving for chips, fast food etc: Try unraffinated salt (some of that stuff with a bit of colour to it, red etc with crystals instead of pre-ground white salt with additives)
Candy etc (sugar): Fruits, berries (could bake something yourself, preferably using natural sugar and no additives in the other ingreds)
100% butter with that less bread instead of "healthy" "natural" "oils". Just use less of it.
If whatever you're eating isn't edible without (atleast) several additives, it probably isn't worth eating.
Sometimes there isn't a 100% perfect option, but take the best one.
Forgive potential formatting, language etc.