Everybody knows how badly people got screwed over with mercury amalgam fillings. Now we are in the age of plastics, and we're wondering why so many people are effected by plastic toxicity creating all these soyboys.
Forget plastic water bottles or tupperware. Not to say those can't have an impact, but if you've got plastic literally in your mouth constantly under varying pH conditions, you're leaching far more than plain water in a bottle would.
Sure enough, when I looked up if BPA was in modern dental fillings, it is. What are the odds? The dental websites claim it all dissipates soon after the filling. Anything after that is negligible they say. But didn't they say the same about Mercury fillings? "Don't worry it isn't going anywhere, it is very secure in there". Bullshit, I say use your common sense.
Fasting is tough since it can expose your nutrient deficiencies. Many people are deficient in potassium and magnesium which will really show itself during a water fast. It's why juice fasts are probably the best bet for most people. Assuming it is a quality juice potassium will be high. Carrot juice is optimal IMHO, very high in minerals and low in sugar compared to most juice.
Just a glass or two throughout the day, and the rest of the time sipping sugar free electrolyte water along with small amounts of b vitamins.