I did something similar not very long ago before a party. I googled how to lose 5lbs in 5 days or something like that and just followed what it said to eat and it worked! Other tips are to have a glass of water with half a lemon squeezed in it first thing in the morning, and if you can stand it a tablespoon of cider vinegar in water once a day. I found that to dilute it with sparkling mineral water somehow makes it more palatable. Plus the obvious exercise tips, park your car further away from the entrance to Tesco, walk up stairs and shake your head slowly from side to side when people offer you chocolates or alcohol.