Loose weight or loose size? I am guessing that you want your physical appearance to change more than your actual weight.
For a quick, short-term change you could start with cutting back on your sodium intake. I know many people who swell when they drink too many sodas or eat too much salty food. When they force themselves to cut the soft drinks and salty foods (such as pickles and those convenient peanutbutter crackers and chips you can get from snack machines) out of their diets, the swelling goes down. And their weight drops a little. Just remember, you do need some sodium in your diet. So don't go overboard and only buy foods that don't contain it.
Choosing water when you are thirsty will also cut back on the number of calories that you consume durring the day, which will in turn lead to healthy weight loss. ... Don't go overboard on this either though. Too much water can be dangerous, even fatal.
10 days should also be enough time to loose weight through a healthier diet and more exercise. Try getting more fruits and vegetables in your diet and cutting back on the higher calorie items. ... Have you ever considered seeing what it is like to be a vegetarian?
There are also some 'cleansing' liquid diets out there that can lead to rapid weight loss and are quite safe when done properly. However, make sure that you know what 'cleanse' really means. If you decide to go this rout, you may spend a lot of time in the bathroom for the first couple of days. This wouldn't be convenient if you have a job, school, or other important duties that need to be taken care of on a daily basis.
Watching what people I know have gone through to become healthier or loose weight.
I have also personally experienced rapid weight loss through extreme diet and exercise changes - 9 pounds in 4 days from eating only homemade soup (unsalted vegetables and chicken breast simmered in a mixture of tomato sauce and water), drinking only water + 1 glass of milk per day, and doing cardio exercise videos 4 times a day. ... Going until my body said it was time to quit instead of until the video said time was up. ... I think this diet was a little too extreme.
I have also gone through a period of loosing a steady 1 pound per day through eating whatever I had a craving for at breakfast, having a healthy, 'sensible' lunch (such as a salad and a small bean burrito), and allowing myself only fresh "negative calorie" fruits and vegetables within 6 hours of bedtime. Within that 6 hours before bed time, I only drank water. Earlier in the day, I allowed myself water, 1 cup of fruit juice, and 1 cup of milk.
Through all of the answers that you recieve, I hope that you can find a plan that works for you :) And remember that long-term weight loss can't happen too fast. If you want to continue getting in better shape, the best way will be through finding a healthy diet and suitable exercise.