When you look at the list of ingredients on food or drink, at the very end you'll notice some pairs of colors and numbers. For example, this bag of Doritos sitting next to me shows Yellow 6, Yellow 5, and Red 40.
That's not good.
Those are dyes, meant to make a lot of the food you buy look like something you'd want to eat. There are plenty of drinks out there that could easily go without any color at all. But you as a consumer don't want that. You want your grapes to be purple, your oranges to be orange, your razzleberries to be somewhere in the color spectrum you normally associate with berries.
Red 40 is one such dye, and it is widely used in the United States. Like clothing made in China, you have to go way out of your way to even start reducing the amount of it in your house.
Why is that bad? Because Red 40 is a petroleum-based dye, linked to health problems on down the road. Not immediately, but later on. It's been banned in Austria, Belgium, Denmark, France, Germany, Sweden and Switzerland. (Yellow 5 and Yellow 6, the other two mentioned on the Doritos bag, have shown a good deal of molecular similarity to Red 40.)
Essentially, every time you buy a food product with Red 40, you buy a tiny bit of oil. And then you eat it.
That second link is part of a website devoted entirely to Red 40. It's worth a click.