Watch what you drink!
Do you know that soft drinks are the main source of added sugar in food? What's worse, these "liquid calories" don't seem to register in our stomach like food calories do - they don't fill up or satisfy our hunger as well as solid food calories. Let's do some math, shall we?
A small extra of 50 calories/day adds up to a weight gain of about 1 pound every 10 weeks, i.e. more than 5 pounds/year.
Hence, it is much better to reduce your intake of sodas and replace it with water.
If plain water doesn't do it for you, add slices of lemon, lime, or orange for flavour and vitamins without the calories!