Intermittent fasting and hair loss?

Fasting does not cause hair loss. When you eat the body will get the necessary nutricions. Unless you are fasting for a long time than it can cause hair loss.

Fasting with significant weight loss has been known to precipitate hair loss, especially if there is any genetic component present

Weight loss over a short period of time, as well as nutritional deficiencies in animal protein, vitamin B-12, vitamin D, and iron, can all influence hair loss.  Gradual weight loss and making sure you are not deficient in those areas are advised to prevent hair loss.  Good luck!