Hi there... hey, sorry to hear about your injury
I just happened to see your post on the main page and thought I'd comment. While I didn't whack my ankle as bad as you did (wow, you must have been playing hard!)... I have had biomalleolar fractures in both legs at different times. I have an underlying neurological problem (bi-lateral footdrop) that makes it super easy for me to roll out my ankles.
Anyway, I had surgery on both of them with internal fixation. A plate and six or seven screws on each of the outer ankles and two long pins on each inner ankle. Surprisingly, the surgeries and healing went pretty good... no major problems from either. If you want any further info on any of that, or reassurance... just PM me.
As far as weight loss, just to give you some hope here... I've been walking on crutches for the last several years (due entirely to the neuropathy, not due to the previous fractures)... and my weight loss so far has not been a problem since starting on New Years Day. I don't do much walking, only about a 1/4 mile a day total, and I sit all day at a computer at work. Still, I have managed to lose 18 lbs in 9 weeks (about 2 lbs a week) just through diet alone. And I'm not starving either... I eat between 1200 and 1700 calories a day, but of course since you weight less yours would be a little different.
Sorry, didn't mean to ramble. Just wanted to offer some reassurance that diet alone may not get you there as fast, but being off your feet for a while doesn't have to be a weight-loss killer either.
Good luck!!