I sympathize with your position so much. I'm 28 and my mom still freaks out over what I eat/don't eat, workout, when/where/how much I sleep, what shampoos I'm using etc. My mom would 100% respond the same way if I ever told her I was fasting. My guess is the intensity of her reaction is at least 50% a response to you starting a new chapter(which changes the role she plays in your life). How I deal with my mom when she freaks out over something I'm doing is to make sure steering our interactions to other things where she might be able to have input. The goal is to refocus her attention and also to make her understand I value her input and her concern by giving her another outlet to demonstrate those things. Also, moving out was the best thing I ever did. At 17 I moved a mere 45 minutes away and it actually improved my relationship with my mom drastically because whenever we argued or got into very emotionally charged situations, it provided the space and opportunity to disengage and let things cool off.