I heard green tea can help you loose weight by drinking about 3 cups a day. could it actually be unhealthy?

3 cups of green tea: As long as it is not a sugary or fake green tea with a bunch of added stuff, will still be healthy for you. It will have some caffeine at three cups though, about equal to a cup of coffee, so if you have hypertension or anxiety, be a little careful, otherwise three cups (6-8 ounces per cup) will still be healthy. Weight loss idea comes from a mild binding to dietary fats, not much though.

It is usually: Recommended that you limit yourself to five cups of green tea per day or less. If you are sensitive to caffeine - caffeine free green tea is a better option.