Food manufacturers like Kraft, General Foods and Nestle have used these scientific formulations to enhance their profit margins knowing full well that the food they produce is bad for our health.
Initially, pre-packaged foods were something eaten occasionally. They were "convenient" but lacked flavor so they weren't very popular. Eventually food manufacturers discovered the right formula to make their products both flavorful and addicting. This is why it's hard to eat a few chips, crackers or cookies. These "products" have few real food in them, this is why it is so difficult to get the exact flavor when making a homemade version. They use ingredients that are unpronounceable and we have no idea what they are.
It doesn't take much to change your taste buds to like foods with less salt, sugar and fat. If you do still feel the need to use "convenient" foods, use them in the spirit they were intended, eat them infrequently.
Click here to read an informative article in The New York Times.