The only thing making me loose weight was 5 month studying abroad in Ghana (I'm from Germany).
The ridiculous thing about it was: I didn't intend on loosing weight there. I ate as much as I liked whenever I liked it. Still, I lost about 15 kg in 5 months, and I didn't even notice it until the end of the trip when another student told me that I looked like it.
What I noticed as a big difference in my habits: * no Drive-In, no McDonald's, no Burger King, no other franchise. So, no junk eating while driving (e.g. from work) * no fridge at the hostel (at least none you would want to use). So, no "I'm bored and will just get something from the fridge" * I'm not a cooking person, so almost all food required walking the 5 minutes to the small market. Not a long way, but it keeps somebody like me from boredom eating * the fucking heat =D no movement and a lot of sweating ;-)