A few notes:
- re: your friend - it sounds definitely like she is feeling some serious self deprecation and is projecting on others. The best frame of mind in which to lose weight is one of self love, not one of self hate. I am one of those who has had many "false starts" at weight loss and the ONLY time that I was successful at losing 50lbs or more and KEEPING IT OFF was when I was doing the whole thing not because I found myself "disgusting" or was really really disappointed in myself, etc - but because I loved myself and knew that my body and my self was absolutely worth putting the time and effort into working out and preparing healthier meals for myself. It took a long time for me to get my head in that space, but my entire life has been improved - not just my health, but my outlook, my struggles with depression, my career, EVERYTHING has improved since I started saying "you are WORTH it. You DESERVE it." And I had to understand and know this about myself even when I weighed 325lbs. Without it, I would have gotten nowhere.
- re: yourself. Life is too short to waste with people who genuinely don't make you feel good about yourself. If you don't have a desire to truly help or support your friend other than because you need to honour your friendship and not because the friendship has been mutually beneficial for the both of you, then it is time to get out. Ultimately, everyone is responsible for themselves, and if you can't handle the negativity, it will drag you down. You can't beat the above mentioned self love into her, she has to come on to it on her own.
- re: "fat people in denial" - I sure hope that was tongue in cheek. The obese, I think, as a general rule, are extremely aware of the differences in their bodies. Just because one doesn't shut oneself in and wallow in the fact that they don't fit society's ideal doesn't mean that they are "in denial" about their weight. I highly suspect the person mentioned in the OP is indeed not in denial, but is not feeling very good about herself right now and is using it as an excuse to feel not very good about other people.