I believe you meant a food label, so always know/look at your fats. And definitely look at the rest of the ingredients list, but the first thing you should look at is the fats.
Because the kidneys cant get rid of all toxins in the body.
The three R's for nutrient preservation are to reduce the amount of water used in cooking, reduce the cooking time and reduce the surface area of the food that is exposed. Waterless cooking, pressure cooking, steaming, stir-frying and microwaving are least destructive of nutrients.
hope this help<3