No time but Must to Lose some weight!? Hmm...?

I heard that people can easily lose their weight by eating Watermelon. So I wanted to take a try on that diet but the problem is that in my Country the Watermelon season is not yet. Moreover I need to lose at least 15 kgs in 20 days. Do you possible know any other diet like this one? Lose weight without starving? Also about the exercise I do workout but these days I am very Busy that I cant even exercise properly! :(( Please Help Me to Solve My Problems!!! Thank You!!! :))