If you are going to buy anything packaged, then take the time to read the food labels. If it has more than 5 ingredients in its probably too processed. If it has things in the ingredients list that you can't pronounce, your body won't do well with digesting it. The more the packaging tells you its low fat, low sugar, healthy, good for you, the more it is not good for you! While the fruits and vegetables and meats that are say nothing are the healthiest for you!
Enjoy the Animaniacs video on food additives.