Do you know you eat too much? Are you counting calories? Keeping track how much of your intake is fat vs carbs vs protein?
You can eat how much and whatever you like (just keep an eye on good nutrition and vitamins). BUT: depending on your goals (loosing weight, not gaining, getting toned) you have to check your eating-activity balance.
Know that for each kg of body fat you have to burn 7000 kcals. This means 11 hours of really tough cardio - I am not talking a nice little walk! Know that for one freaking Big Mac (no fries or soda!) you have to run for almost one hour!
Keeping that in mind, start counting the calories you eat (there's many apps out there), tracking your workouts with a heart rate monitor (to evaluate what you are burning, at least roughly) and calculate (once) what your body burns in rest (there's calculators on the Internet).
You finally will be able to know, where your lifestyle leads you: are you gonna lose (burn more than you eat) or gain weight. And than you can play with the results - enjoy :-)