I'm 16 now, 176cm-ish. was nearly 90kgs when i was like.. 14 or something. Then I started doing stuff like this, walk to a mamak shop 15 minutes away from my house, buy 3~4 packets of Iced Teh 'O' and walked home, did that once a day every day in the morning, sometimes twice. Ended up 64kg after 2 months. Of course, I cut down on food less by 30% or around that.