Our body needs fuel to think, run, grow, and stay healthy. That fuel comes from food. The three main nutrients that give us energy and strength are:
Carbohydrates, Proteins, and Fats
Let’s learn what each one does and how our body uses them.
Carbohydrates
Carbohydrates are our body’s main energy source. Carbohydrates are important because they are our body’s primary energy source, keeping organs such as the brain and muscles powered.
When you eat carbs, digestion begins in your mouth, where a strong liquid called saliva breaks them down into small sugars. Then the carbs get digested in your stomach and slowly move to your small intestine, where a special substance called enzymes breaks the carbs into a basic sugar called glucose. The glucose is absorbed in the small intestine walls and is sent to your bloodstream, where it starts to circulate throughout your body. Our cells use glucose to produce energy that helps us think, move, grow, and stay active.
Here are three main types of carbohydrates, and each one helps the body differently.
| Simple Carbs | a sugar made of 1 or 2 sugar units | Digests very fast and quickly and turns into glucose | fast energy that doesn’t last long | found in sugar, candy, honey, soda, and fruit juice. |
| Complex Carbs | long chains of sugar units | digests slowly and releases glucose over time | slow, steady, long lasting energy | found in brown rice, oats, whole wheat, bread, and vegatables |
| Fibers | a carb that is not digestable by our body | does not break down into glucose | no energy, but helps digestion | found in brown rice, oats, whole wheat, bread, and vegetables |
Proteins
Proteins are the building blocks of the body. They are very important for building muscles, bones, skin, and tissues. Proteins also help with growth and repair, make hormones and enzymes, and produce antibodies that protect the body from illness. Most of the time, protein is used to build and fix the body, but it can also be used as a backup fuel when carbohydrates and fats are low.
When the body needs energy and does not have enough carbohydrates or fats, it can use protein as a backup energy source. First, protein from food is digested in the stomach and small intestine and broken down into small pieces called amino acids. These amino acids usually help build muscles and repair tissues, but when energy is needed, they are sent to the liver. In the liver, the nitrogen part of the amino acids is removed, and the remaining parts are converted into substances that can enter the energy-making process. Cells then use these substances to produce energy, helping the body function when other energy sources are low.
Fats
Fats are a crucial nutrient and macronutrient that provide a large amount of energy. They help build cells and tissues, protect organs, and keep the body warm. Fats also help the body absorb important vitamins such as A, D, E, and K. Because fats contain a lot of calories, they are an excellent source of stored energy.
When we eat fats, digestion begins in the small intestine. Bile from the liver and gallbladder breaks large fat pieces into smaller droplets so they are easier to digest. Enzymes then break fats down into fatty acids and a small, sweet molecule called glycerol. These tiny pieces are absorbed in the small intestine and enter the bloodstream, where they travel to different parts of the body. When the body needs energy, fatty acids enter cells and are slowly broken down to release a large amount of energy. This is why fats are an important source of long-lasting energy, especially when the body is resting or doing activities for a long time.
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