To lose 10 pounds in 10 days, you should burn 35,000 calories in less than 2 weeks. It is difficult to do, but it can be done. The trick is to combine a smart diet with exercise and heath supplements. This trio of action helps you burn calories as efficiently as possible and achieve your desired weight loss. Cutting your calories enough to lose body fat during this time requires dropping below the recommended number of healthy calories for an adult.