Living things contain the element carbon. That is because many organic compounds are present in living things such as carbohydrates, lipids, proteins, nucleic acids. Organic compounds contain both the elements Hydrogen and Carbon besides any other elements that may be present in a compound. Therefore, anything that was once alive that you cook and subsequently burn, will turn black and the charred material will definitely contain the element carbon. For example, if you cook a steak, and burn it, the protein and lipids inside the steak as well as any stored glycogen, all contain carbon. If you eat vegetables, fruits, meats or anything derived from a living thing, there will definitely be the element carbon in those foods.