How to test if your health problem is food/drinks related/caused?
Stop eating for a 7 - 21 days period, and live just on pure, cleanest water available.
If your condition is reaction to something you eat/drink every week, it will show signs of improvement while water fasting.
How to test if your health problem is a result of your nearest environment, like air, water (house/office/city)?
Move to a hut on a clean high mountain, and try living there for 1 - 3 weeks. If your condition is reaction to something in your nearest environment (like industrial toxins, black mold, bad water, bad radiation etc)
it will show signs of improvement while on the mountain.
How to test if your health problem is a result of poor liver condition?
Go on clean diet and perform several Liver Flushes with 2 weeks appart. If your condition is related to your liver, it may show major changes after a Liver Flush (getting worse or getting better.)