Timescale...

boopboop120

Currently, I'm 154lb (11st). I do an hour of karate a week and a 30-45min walk over hills each day, usually eat 1200 calories net or under, and measure 36-29-38 (bust-waist-hips), uk 12.
How fit will this make me and how long would it take to get down to 34-27-36 (uk size 10)