There are various ways to lose weight but the most effective way is the healthy way.
Any kind of faddy diets, or starvation, will only result in you gaining more weight than you lost. A healthy amount of weight to lose in a week would be 3-5 pounds.
But this depends on how many calories you consume per day, and is based on a healthy calorie intake.
The fastest way to lose as much weight as possible is a balance of exercise and eating right. You may need to discuss your needs with a personal trainer who can advise you on the appropriate balance of cardio and weight training.
Weight training is said to burn more calories than simply cardio, and continues to increase your metabolism for the rest of the day.
In terms of your eating, it is also a good idea to set a food diary for yourself. During your intense training, you may want to consider increasing your protein intake and decreasing your consumption of carbohydrates.
With that being said, you should never completely cut out any food group. Doing these things will help you lose weight quickly, but safely, which means that it will also set up a lifestyle with your new weight, not just temporary and reversible loss.
I hope this helps.