Sureshot said:working out usually means gaining weight, as working out turns fat into muscle usually (and muscle is heavier then fat, though more dense so more toned). if someone is tryin to lose weight you've got it all wrong, its better to just concern yourself with 'getting into shape' which is entirely different than weight loss (though getting into shape means more defined muscles, and muscles tend to use up fats faster turning it into energy). thats why i can't gain weight lol, im toned and have a poor appetite.
most people get screwed over if they try to lose weight because most diet things actually convince them to not workout (why workout when they're eating diet foods?!) and most diet foods are addictive and make you hungry (so you have the diet drink often for instance, then end up feeling hungry, and it happens often due to the addictiveness... so the drink is not directly to blame, but it causes factors defeating dieting purposes).
the best way is just to be active and practise exercises because they'll give you more energy, not because you expect to lose weight quickly.
Just as a side note, I picked up 25 lbs ( 11 - 12 kgs for others) over frosh year and decided to lose it. Just hauled myself back into shape with 10 mi runs, just to restart the metabolism. I've dropped about 30 now, so I've cut it down to 5 mi so I have more time to do other stuff (like play CIV).