A realistic goal is to lose 1-2lbs per week. You are NOT going to lose 20lbs in a week, no matter how hard you try. You should Just lose it week by week. Try the 500calorie diet where everyday you either burn 500 calories, or eat 500 calories less. And by the end of the week (it's 3500 calories to the pound) you'll have lost a pound. So a pound or two pounds each week (depending on how hard you try)- you'll have lost 20lbs in 10-20 weeks. Just take your time.
You might be able to lose 10-14 pounds in a week, but you would be very very very sick, and very hungry, and thirsty, and unhealthy. If that's your goal, ok, but if it's just getting to a better weight, just do it a little at a time, and whatever your reason is for losing 20lbs immediately, you need to let it go.
There is NO WAY, safe or unsafe (except for surgery) to lose that many pounds in a week. Healthy weight loss is about 1-2 lbs.
Eating health and exercising, is the only way to go about losing weight AND keeping it OFF.
You cant, thats an impossible and unhealthy goal. If you want to loose weight you have to be realistic and prepared to put in the work. Eat healthy and excercise.
well you can do it with a knife. if that doesnt suit you. then GO WORK OUT IN THE GYM EVERY DAY FOR 2 HOURS AND STOP EATING AT MACDONALDS