Congrats on the weight loss! I lost 1.5stone between Sept & Dec (have piled it back on since having a kid ). Low calorie diets coupled with exercise works wonders.
But I changed what I ate during the week - low carb lunches with protein. And I do attribute some of it to exercise (lots of walking after work and over the weekends), but it was easier having lunches that kept me full til dinner, but changing the snacks I'd have. Replacing crisps with fruit/nuts etc again something to keep me fuller.
I used my friend's wedding in Sept as my final time to have a drink - I cut alcohol out and that also made a difference.
I'd be quite disciplined as a lot of it is down to will power, too.
Good luck though!