I almost always skip my period whenever I go on a diet. I went on my first diet when I was about 16 and now I'm 21. Whenever I stabilize or even sometimess gain weight
I always return to my normal cycle. However, I've never missed then about two or three. I've always wondered if it was normal but I don't think it's a problem. I would suggest though if they miss more than about three or four I would see a doc.