I would have a conversation with them and let them know you would like the support not grief. Not that they would. I am blessed to have the support of my whole family. I explained I was in need to get healthier and not the fad diets. you can give them all the information. If they have questions beyond what you know, invite them to come to your next appointment so all there questions and concerns can be addressed. Let them have some websites to do a little research for themselves or show them what you have learned by showing them the info you found. that you have made an informed decision. Hope that helps.
Keith