My advice is to shop on the perimeters of the grocery store, where fresh food are stocked. Stay away from processed foods and that includes soft drinks.
Foods that are processed contain lots of chemicals. Some are used as preservatives or as colorants. Coke and Pepsi have been using methylimidizole, or 4_MF1, a know carcinogen. Wonder how longe they' been using it? Now the FDA says, "No", its' too dangerous. Coke says "it isn't" but they are changing the formula.