Our bodies rely on six essential nutrients found in food: carbohydrates, fats, proteins, vitamins, minerals and water.
Carbohydrates are the body’s most important source of energy. Carbohydrates are organic compounds that are either simple or complex. Simple carbohydrates are sugars found in fruit (fructose), milk (lactose), and table sugar (sucrose). Complex carbohydrates are commonly known as plant starches found in breads, beans, rice, potatoes, vegetables, fruits, and pastas.
Most of the calories you eat everyday should come from complex carbohydrates. Simple carbohydrates are sugars. Complex carbohydrates are generally whole foods (grains, vegetables, legumes) with valuable nutrients and fiber.
Fat (lipids) provides insulation for the body and padding around internal organs. Some dietary fat is needed as a source of essential fatty acids for fat soluble vitamins. Several nutrients are found in fat, including vitamins A, D, E, K and essential fatty acids. Fats are important in our diet, particularly triglycerides and cholesterol. Triglycerides are the main form in which fats stored in the body.
Fats are either saturated or unsaturated. Saturated fats have been linked to heart disease and raise the level of cholesterol in blood. This is the kind of fat you don’t want to eat. Some vegetable foods contain saturated fat like nuts, margarine, coconut oil, or palm oil and chocolate. Saturated fats and cholesterol are found in animal foods like butter, cheese, red meat and animal fat. The combination of too much saturated fat and cholesterol is bad for you. Cholesterol is made in the liver of animals and is found only in animal foods.
Unsaturated fats in small amounts are better for you than saturated fats. Unsaturated fats are found mostly in oils like canola, corn, cottonseed, olive, peanut, safflower, sesame, soybean and sunflower.
Proteins help muscle tissue develop and function. Protein is needed to make hair, skin, nails, muscles, organs, blood cells, nerve, bone and brain tissues, enzymes, hormones, and antibodies. Protein and amino acids are found in both plant and animal foods. Amino acids are the building blocks for proteins.
Vitamins are complex organic compounds found in small amounts in most foods. Vitamins do not contain calories and therefore do not provide energy. However, vitamins are important for metabolism and for our organs to work properly. Vitamins C, folic acid, and all of the B vitamins are water soluble. Water soluble vitamins are passed out of the body in urine. They do not build up and harm the body. Vitamins A, D, E, K, are fat soluble. They are stored in fat cells. Too much of these vitamins in our system can lead to toxic build-up.
Minerals do not contain calories, but are important to many bodily functions. There are two groups of minerals: major minerals and trace minerals. Major minerals include calcium, phosphorous, magnesium, potassium, sulfur, and sodium. These minerals are found in a variety of foods including milk, meat, poultry, fish, and green, leafy vegetables. Trace minerals are needed in small amounts: they include iron, zinc, manganese, copper, iodine, and cobalt. Trace minerals are found in shellfish, seafood, whole grains and legumes. Minerals often work together. Too much of one mineral may upset the balance
of other minerals.
Water is important for the other nutrients to function. We may survive for weeks without food, but only live a few days without water. Water has no calories and does not provide energy. However, it has a key role in metabolism, particularly in the regulation of body temperature. Our main source for water is from fluids. Water, soda, milk, coffee, juice, and tea provide inorganic sources of water. Solid foods, such as lettuce, celery, melons, and most fruits contain organic sources of water.
All food provides calories. All calories provide energy. However, calories that do not come with vitamins, minerals, fatty acids, amino acids, and fiber are called “empty calories”. Empty calories give you energy without nutrients. Table sugar and alcohol are examples of empty calories. Eating too many foods with empty calories can cause health problems.
That’s why it is important to learn how to choose foods that provide nutrients and calories. All calories, no matter where they come from, give you energy. If you take in more energy (calories) than you spend (burn off through exercise) you gain weight. If you take in less energy than you spend, you loose weight.
Which foods have the most calories?
- one gram of protein has 4 calories
- one gram of carbohydrate has 4 calories
- one gram of alcohol has 7 calories
- one gram of fat has 9 calories
Carbohydrates and proteins are better sources of nutrients and have less than half the calories of fat. That’s why foods high in fat are also high in calories.