I think you’re talking about Breatherism? There’ve been a couple of those cults all over Europe. It’s not particularly popular, luckily, but they often make it to the newspapers, because someone usually dies.

It originates from Hinduism though. There’s a another Indian religion called Jainism. These are the monks you see brushing away the beetles before their feet, to not step on them. It’s very much about nature and spiritualism and being good. Fasting is a key concept of this religion and the most extreme cases will choose to fast until death to cleanse the world. This is all very spiritual though and takes years of preparation.