Carbon atoms make up a large part of our molecular structure, and without them the many other elements that make up our bodies would not be able to cohere. We are a "carbon-based" life form. Our supplies of carbon get used up as we go about our lives and frequently need replenishing. Carbon is therefore an essential part of the human diet, and it is in plentiful supply. The fruit, vegetables, grains and meat that we consume all keep us fueled up with carbon.
Our intake of carbohydrates, fat and protein supply us with carbon in the form of large molecules called macronutrients. Most of our diet can be classified into one of these three categories, all of which are carbon-based but have differing chemical properties. Virtually everything we eat contributes to our carbon content.
Food is essentially carbon dioxide. The plants we eat directly, such as vegetables, have all absorbed carbon dioxide out of the air through the process of photosynthesis, and the animals we eat have all ingested it via the grass and plants they eat. Ultimately, everything that is organic gives its carbon back to nature through death and decay. This is called the Carbon Cycle.
Carbohydrates are the most common source of energy for all living things. They come in two forms -- simple sugars and complex carbohydrates. Sucrose is the most widely known sugar, but there are several other simple sugars, including glucose, which is found in blood, and fructose, which is found in honey.
Complex carbohydrates are found in grains and starchy vegetables -- potatoes, for example. Eating more complex carbohydrates, especially whole grains, helps maintain blood sugar levels. All carbohydrates eventually break down to glucose, a molecule made up of carbon, hydrogen and oxygen. Glucose provides energy for the body. Pasta, bread, cereals, beans and rice are all rich in carbohydrates.
Fats are often portrayed as unhealthy, but some are essential to good health. All fats contain carbon. Monounsaturated and polyunsaturated fatty acids mostly (but not exclusively) come from plants. Oils including olive oil, sunflower oil and fish oil contain important elements that the body cannot synthesize for itself.
All the cells in our bodies are built from protein, which in turn is built by 20 types of amino acid. These essential acids are formed by combinations of carbon and several other atoms. Although adult bodies can synthesize 12 of the acids from their carbon content, they must get the other 8 from food. Meat, milk, eggs and cheese contain all the missing amino acids.
More than 30 elements are important in helping plants and animals live and be healthy, with carbon perhaps the single most important because of its ability to combine with other elements. Almost every part of our bodies is made with large amounts of carbon, and the most effective way we have of sustaining essential carbon levels is through the food we eat.