i actually lost weight while munching the hell out with huge meals. fortunately, the markets closest to me sucked so i was forced to walk to markets 3 kilometres away and another 3 apart just to get the food i wanted. then after going there and shopping, i had to lug all that food back home so in the end i was always a bit worn down and plenty hungry when i got back. i guess if you live in london there must be plenty of options for markets so just dedicate a few hours every few days to walking to the furthest ones and picking out the best food. be sure to take a nice big backpack and a few extra bags to fill, an mp3 player to keep from boredom, and wear clothes to match the weather.
now that i think about it, i suppose it also helped that what i ate most often at the time was wraps. they're big and filling and aren't many calories because there's not much bread in it, and a lot of the filler is calorie-free lettuce and tomatoes. they're also quick to make and really tasty, especially when you microwave the shell and meat and cheese before adding the lettuce and tomatoes mmmmm i could go for one right now!