first of all, who ever is telling you that you need to lose 7 pounds in one day is dumb because NOT EVEN and anorexic can lose 7 pounds in one day even if they tried, sorry to break it to you, but you can't do it sorry. just try to get off as much weight that is not a part of your body off as possible(like shoes, watches, wrist bands, anything...make it lighter some how.)
It is not practically possible to lose any significant weight in one day, but you can run a crash weight loss program in the next 2 months or so. Start on a diet that mainly includes green vegetables with very few calories and drink as much water as you can. Exercise frequently, and set aside at least 45 minutes of aerobics is best. Be sure to maintain healthy eating even as you start on the weight loss diet.
The same way we've always done it, dehydrate yourself. Put on the old rubber suit & hit the sauna--of course it takes more than a day to recoup it's really your only option, unless you don't mind a colon cleansing-you can dump 5-15lbs. either way you're going to be aflounder on the mat
You can't do it, in a day alot of these suggestions will have you passed out somewhere or worse. Now this is possible i will give it a week. Before you work out you are suppose to eat, you are suppose to stay hydrated because the body is all about survival, so if go out with some of these actions your body will go to its backup supply and moreso you will not loose weight and if by some insane it does it will come will some negative response. You should accept you and make it work for you, because i mean really you can't even be that bad you asking people about 7lbs, child rock what you have to wear and work on those 7 in a weeks time, the healthy way
Loosing weight in 1 day is not really possible BUT waking up earlier doing exercise is good and cut your meals at least half, ( don't starve yourself, it's not good if your not use to it). Uhh, eat celery, it has no calories ( or is it very less) umm, drink water go swimming or go for a run because for swimming, you are actually exercising your whole body. umm hoped that helped a little