Some people will never, I mean never ever know what it feels like to go through a weight gain/ loss cycle. To them, you never did enough effort. To them, you are a person who is lazy, eat to much and doesn't have any self control. So don't be angry about her commit because she has no clue. No one know you more than yourself so keep doing what's good for you.
Don't keep telling people about what you think is good for yourself. I'm 30 years old now and I've wanted the band since I was 25. My ex-boyfriend made me feel bad about wanting to have the surgery. He felt just like that girl at your job. He has the body type that never needs to workout and always stay fit. So for year I was killing myself at the gym and feeling bad for myself because I just never could keep the weight off. I finally find out that I have a hormonal problem (PCOS) which affects my weight and having children. So guess what? Five years later with one less issue in my life (X- boyfriend) and a lot to look forward to. I'm having my band surgery on 3/26/10 and I can't wait. So do whats right for you. Good Luck.