All I can say is if you love the man you have to listen to his mother!! Just try not to let her get to ya!! As someone who has struggled with weight it is quiet an accomplishment to lose 60lbs and when you lose that much you want to share your diet secrets with everyone - who wants their friends and family members to have HEALTH problems due to being OBESE.
I have just learned to tune my mother in law out - it gets worse when you have children -LOL. My mother in Law - wanted to tell me how she did everything when her children were babies - that was over 30 years ago - I read up and know what has been found acceptable - some of her parenting practices are not seen as WISE and made for battles/ arguments. I just learned to let her tell me how she did it- Then I would RAISE and HANDLE my children the way I felt was RIGHT!!
all I can say is GOOD LUCK !!