I look at the price tag mostly I avoid processed foods. I think if you cut them from your diet and eat real food, it doesn't matter as much what is in it. Your body does not recognize processed foods. Take for instance trans fats. Trans fats are hydrognated oils...like crisco, its oil blasted with hydrogen until it holds a solid form. Your body says...wtf is this? And stores it like a saturated fat(Animal Fats) because its structure is close to it, even though it is not. This means...your belly grows quickly...like you're eating lard to build fat and make it through winter, in the wilderness... If you eat real food, your body knows what it is and how to break it down. Ultimately we eat to supply us with energy not to store fats that our body has no idea how to break down. So eat real food. K. Rant over
I look at the ingredients, as whether or not I can pronounce them. If I have to look up the words I try to not consume as well as buy it if I dont have too.
Also for weight wise stay away from white anything: bread, rice, potatoes. They all turn straight to sugar and doesnt keep you as full aslong as whole wheat breads and brown rice and sweet potatoes do. Alot of the times when something says low calorie or no sugar, it usually contains loads of fake sugar. Which in high amounts can be really bad for you and do the opposite of your intentions.