I lost almost 2 stone when i got my first girlfriend. My mother was like "where is it going, is she stopping you from eating!?!?" bless her. Trouble is, after about 10 years on and an ongoing relationship, almost the inverse is true
As for trimming your tummy, apart from eating/drinking less and walking more, the best method is sit ups / crunches - lots and every day. Start with 20 a day for the first week, then 50 a day for the next then go up to 100 (split morning and night in needed). Eventually aim for 100 morning and 100 night after a month or two. You will be amazed at the difference and you will eat less too.