Would you please mind expanding MBC BC

MBC - Most Backward Caste

BC - Backward Caste

No caste never change by any procedure. if you deside to marry each other than go for it. Veg - Non Veg is just human nature .. change if it require

legally it is not possible to change the caste once entered 

and as explained its only human behaiour that you want veg or non veg 

so you alone can change to non veg making whole family change to veg 

but changing from non veg to veg is better in my opinion 

Let me tell you that one BC caste in one state becomes MBC in another state or some times SC in another state.  Vice versa.  A person can become Vegetarian or non-vegetarian according to his own choice.  If he stops to take non-veg. on the dining table to respect your emotions, what more do you want?  If you love each other, you should not bother about this BC or MBC and can proceed further.