some easy rules.

1. don't drink your calories.
1. don't eat fast food
1. eat out of the fridge-not the freezer. 

now.. of course it won't kill you to go out once in a while and enjoy a hamburger and a nice cold coke. but do these things SPARINGLY. you will eat more fresh things, nutrient dense foods, and have way more energy.

don't diet. don't count calories (unless you have extreme health problems or do competitions or something).
if you let food overtake your thoughts... that is when serious problems can arise.
people always think "well I won't get an eating disorder" and that may be true.
but you COULD get something called
disordered eating. 
this is where food overcomes your thoughts. 
you stress about every calorie. 
you don't eat when your hungry. 
you keep eating when you are full.  
you save calories all day because you are so worried. 
you don't eat after workouts. 
you eat something and feel guilty. 
BE CAREFUL PEOPLE. 
this is your body we are talking about. 
it is NOT A GAME.