10 kgs within 15days without exercise, it is very hard to reduce & not possible to lose. It also not healthy way to reduce the 10kg within 15days. In 15 days you can lose 1.5kg with combination of diet & exercise, some of lifestyle modification. Restrict fatty foods, empty calories drinks, junk foods. Choose healthy foods, drink plenty of water. Focus on good fat . Do exercise for 45mins in a day. Sleep well.