All that matters is that you burn more calories than you eat. Wether it's in the form of Lean Cuisine or Special K or fruit salad.
Of course you want to eat healthy foods like fruits/veggies/beans/lean meats/fat free dairies. And limit the sugar, deep fried stuff and pre-packaged anything.
You can find out what your BMR is at this website:
http://www.bmi-calculator.net/bmr-calculator/
That will tell you how many calories a day your body needs to simply function, and then you can find out how many calories a day you burn with sports and also in your every day activities. Once you know that, keep track of what you eat in a day (there are lots of helpful websites just for that purpose out there, like SparkPeople or FitDay).
Once you keep track of everything it's relatively easy to make sure that you don't eat more than what you burn in a day. This will for sure help you lose weight if you really want to.