I agree with you that pseudoscience needs to be separated from actual science, but there's a lot of science behind fasting. There was a good documentary I saw about it on Amazon. If I remember they were mentioning that the USSR had done tons of studies on it but most of those studies never got translated to English which seems like a tragedy. The USSR was serious about science and imagine how much knowledge we are missing out on.

Anyways, if you do a google search you will see lots of studies on longterm fasting and it's heath benefits.