I cannot stop being vain with my looks. My father has encouraged that in me by his criticism of my fat figure, ugly dresses, etc… and by constantly comparing me to others. I have lost weight, but became sick as a consequence. (I have just recovered from an eating disorder).
How can I get over my vanity? I am angry at, and tired of my father. How can I free myself from all these entanglements?
To be obese is not good for your health and at the same time becoming obsessed with loosing weight to the point of becoming anorexic is not good either. In everything, we should be moderate. Do not blame your father for your situation He probably thought he was doing this for your own benefit. What you need now is a renewal of mind. You need to get your mind off your looks and concentrate on more important things.
Make it a point to read the Holy Bible especially the passages related to your situation. "Do not let your adornment be merely outward; arranging the hair, wearing gold, or putting on fine apparel; rather let it be the hidden person of the heart, with the incorruptible beauty of a gentle and quiet spirit, which is very precious in the sight of God" (1 Pet 3:3-4). It will be helpful if you memorize these verses and keep repeating them to yourself.
I am not saying you should not care at all about how you dress up and what you eat. Do that without worry, and do not make these things the main concern in your life. Do not have an anxious mind "And do not seek what you should eat or what you should drink, nor have an anxious mind" (Lk 12:29).
I am sure you have friends who find you nice and attractive no matter how you look. Identify those friends and get close to them for they will give you a great moral support. Most importantly, you have to have the willing mind to overcome this situation. St. Paul says, "And in this I give advice: It is to your advantage not only to be doing what you began and were desiring to do a year ago; but now you also must complete the doing of it; that as there was a readiness to desire it, so there also may be a completion out of what you have. For if there is first a willing mind, it is accepted according to what one has, and not according to what he does not have" (2 Cor 8:10-12). Pray about it daily and have confidence that if you really have the determination, God will not let you down. "Now this is the confidence that we have in Him, that if we ask anything according to His will, He hears us. And if we know that He hears us, whatever we ask, we know that we have the petitions that we have asked of Him" (1 Jn 5:14-15).