Am coming in quite late to this so apologies.
I started dieting on January 13th - I weighed 17st 2lbs at the time. This morning I tipped the scales at 15st 12lbs :)
The reason I have had a lot of weight loss is because on Jan 13th, I (stupidly) agreed to run the London Marathon (not realising how close it was). The furthest I have previously run is 6 miles.
Training is going well so far (16 miles completed last weekend and 8 miles this morning).
Biggest advice I can give - watch this program (if you haven't already) from the BBC (10 things you need to know about losing weight)
https://www.youtube.com/watch?v=bXFXwlNAbME - it's brilliant