How can you lose 16 pounds in 10 days?

At this point, your weight loss is going to be both unhealthy and extremely temporary. That said, you should be able to drop about a pound per day by switching to an extremely low calorie diet (I drank 3 slim-fasts per day) while keeping a high level of cardio. On the 8th and 9th day, cut food down to a single balance bar for energy, take some natural laxatives to purge what little should be left in your system, and on the final 24 hours, drink no water and deal with the dry-mouth. It'll mostly all come back right away, but is doable.