Catabolism occurs when your body begins to break down muscle into fuel for your body to use to live. There are several causes for this, the first being a serious caloric deficit.
The best way to prevent catabolism is to make sure your body is recieving the nutrients it needs. you can still drop bodyfat at only 200 cals under maintenece. If you need to lose bodyfat quickly, make sure your taking in atleast 1.5g of protien per lb of body wieght.
dont bother with glutamine, it is a waste of money. If you want to suppliment get a good BCAA drink, and wome protien powder.
I don't do this for my family, my friends, women, accolades, pride, or ego. I do it for me and no one else, its just part of who I am.