How do I handle this?

I have this friend and she's head over heels for this guy she works with and have been drooling over him for months. Me and her have been friends for many years as we all grew up together. Anyways she finally worked up the courage to ask him out and he told her that he doesn't date overweight women but he's flattered. So she then asked him what if she lost weight and he said he'd think about it then.

She has been killing herself ever since to lose weight and it's just so upsetting. I mean, I'm ecstatic she's trying to get into shape and live healthy but I really wished she wasn't doing this for him. I tried telling her that she deserves soooooo much better than him but she doesn't care. Omg she eats less than 500 calories on a daily.

I wish she would love herself more to know she deserves more.