Carbohydrates are not just those substances you worry about in a candy bar, a slice of bread, or a potato if you are on a diet. They are found in every food, and every living plant, animal, or person. Of all the organic chemical families in nature, carbohydrates are most predominant, comprising 75 percent of all plant life on earth. Your house plant and your peanut butter sandwich both contain carbohydrates.
activity possible, from reproducing a single cell to thinking to lift a heavyweight.
When carbohydrate levels are adequate, you feel full of vigor. Carbohydrates protect your body’s supply of protein from being used for energy, a job it can do in an emergency. But when you eat enough carbohydrates, your body does not have to steal from its fat and protein stores to do the job of carbohydrates giving you energy. The protein can be saved for the important role of manufacturing new cell tissue and maintaining the health of the old.
In your body, carbohydrates are nearly all broken down into glucose, a sugar molecule from which most other carbohydrates are constructed. Glucose is especially essential to cerebral function since the brain cannot utilize any other energy source: a steady glucose supply to the brain is one of your body’s highest priorities. Glucose is in fact the number-one end product of a complex natural process called photosynthesis.
Photosynthesis: The Magic Act by Which Carbohydrates Are Born
All carbohydrates, from the simplest sugars to the most complex starches and fibers, are made up of only three primary chemical elements: carbon, hydrogen, and oxygen.
Photosynthesis is the never-ending process carried on by plants to turn those three elements into carbohydrates. Without photosynthesis, we could not eat. Thanks to photosynthesis, incredible amounts of these elements are turned into edible carbohydrates for human nutrition.
Photosynthesis is a natural form of solar power. Green plants utilize the fleeting energy of a ray of sunlight to create the storable food energy of sugar and starches at the same time freeing the element oxygen for us to breathe.
It is a wondrous process. The key to it is a substance found only in plants: chlorophyll. Chlorophyll is that restful-looking substance that makes the grass on the ground and the leaves on the trees green. It’s found in dozens of foods you probably eat every week romaine lettuce, spinach, broccoli, kale: all the green leafy vegetables. But that pigment isn’t confined just to the leaves and stems of plants; it is found in every one of the plant’s countless molecules. Besides its role in photosynthesis, this amazing universal pigment is also responsible for the magnesium content in many of our favorite vegetables and fruits.
Photosynthesis is made possible solely by the fact that, because of the special properties of chlorophyll, all green plants are able to ensnare the rays of the sun, and use their energy to make food.
For photosynthesis to take place, that blade of grass or leaf of romaine must also pull carbon dioxide from the atmosphere and water from the soil. And then, as you would follow a recipe, it uses energy from the sunlight to combine the carbon dioxide (CO2) of the air with the water (H2O) it absorbs through its roots. Photosynthesis has been set in motion.
In the process of photosynthesis, oxygen is liberated from the carbon of the carbon dioxide molecule and released into the atmosphere. (This process makes animal life possible.) The carbon combines with the hydrogen and oxygen of the water to make glucose energy, in other words, for every activity, you will engage in today, tomorrow, and as long as you live.
Glucose is not the only end product of photosynthesis. However, it is the most important one especially for us, since our brains would starve in minutes without glucose. There are other carbohydrate end products that are responsible for all the rich variety of vegetables, fruits, grains, legumes, nuts, and seeds we enjoy.
Carbohydrates do more than just contribute to our feeling of fullness after eating a bowl of spaghetti; they are more than just a source of roughage in our diets. Carbohydrates are the fuel cells of life. They do one job that neither fats nor proteins can do as directly: provide energy for everybody’s activity, from cell metabolism to running a marathon. They are found in every living thing.
It is thanks to the miracle of photosynthesis that we have fruits, grains, seeds, nuts, and vegetables to eat as well as air to breathe. Through photosynthesis, plants transform the energy of sunlight for storage in leaves, stems, roots, and seeds. This miraculous process, constantly taking place, creates the basic sugars from which all other carbohydrates are constructed.