By combining workouts, you are doing workouts that work a number of different parts of the body at once. These form small muscle tears at different parts. The body burns quite a bit of calories trying to repair those small tears.
Liquid calories, in the form of sugary sodas and juices are a no-no. These are the very definition of empty calories because they won’t fill you up the way food will. If you’re thirsty, drink water.
In order to hit your goal of losing 10 pounds in just seven days, you’ll need to burn a tonne of calories per day. You don’t want to starve yourself but you will need to burn approximately 5,000 more calories that you take in.
Lots of people decide they shouldn’t eat and that will help them burn more calories than they eat. The fact of the matter is you need to start off the day with some food, in order to get your metabolism running.