The human body requires six nutrients for producing energy, tissue growth and development, regulate body processes, and preventing deficiency and degenerative diseases. These nutrients are carbohydrates, protein, fats, vitamins, minerals, and water and are all what are called essential nutrients. Our bodies require these nutrients for basic body functions. These nutrients are put into two categories, macronutrients and micronutrients. The macronutrients are carbohydrates, protein, and fats because the body requires these in large quantities and they have caloric values. That gives us the micronutrients, vitamins and mineral. They are micronutrients since the body needs smaller amounts of them. Water is a class by itself and is needed in varying amounts depending on individual needs.
Carbohydrates are used in the body as energy by converting them into glucose. This nutrient is the primary fuel source for activity. Carbohydrates are stored in the liver and muscles as glycogen and converted to glucose when it is needed for energy production. With the proper intake of carbohydrates the body store enough energy for approximately 90 minutes of aerobic exercise. Foods that carbohydrates can be found in are fruits, vegetables, and grains as well as in milk, soy, rice, nuts, and others.
Protein, in the form of amino acids, are the building blocks of the body. Protein is used in the body for development, growth, and repair of body tissue and muscle. It is critical to maintain and adequate intake of protein to recover from exercise or in the case of sickness or disease. Protein can be found in meat, beans, dairy, grains, and vegetables.
Fats, or lipids, can come from both plant and animal sources. Fats are needed for a nice list of body processes. For general discussion just think of fats as needed for fuel when at rest or during low to moderately-intense exercise. The list of sources of fats are meat, dairy, nuts and seeds, cooking oils, avocados, and some grains.
Vitamins are used by the body in a variety of body processes. Vitamins do not produce energy, but some of them are necessary for macronutrients to be used in the production of energy for the body. They are classified as being water or fat soluble since they require either water or fat for transport, absorption,and storage by the body. Water soluble vitamins are B and C. Fat soluble vitamins are A, D, E, and K. Vitamins can be found in nearly all foods that we eat.
Minerals are unique since they are used in the regulation of body processes as well as structural development of tissue. Minerals are divided into two categories, major minerals and trace minerals. The major minerals are calcium, sodium, potassium, chloride, phosphorus, magnesium, and sulfur. Trace minerals are iron, zinc, copper, selenium, iodine, fluoride, molybdenum, and manganese. They are split into the two categories based on the daily quantities needed by the body. Minerals, like vitamins, are found in a wide variety of foods.
Water is in a category of its own since it plays a major role in the body. Water is found in tissues and fluid throughout the body and represents 55-60% of the body. Water is needed for temperature regulation, lubrication of joints, and the transportation of nutrients and waste throughout the body. Water can be obtained in the water we drink, juices, milk, coffee, tea and other beverages. We can also get water from fruits and vegetables.
These nutrients are why I believe we should eat whole foods and try to stay away from the processed food created by the food industry. I think the use of the term calories in, calories out is the wrong use to think of weight loss or maintenance. Sometime certain nutrients are needed by the body for a variety of reason. Protein is a good example. When they body is broken, diseased, or stressed protein is required to rebuild body tissue. If the body is denied the required amounts of protein to correct what is wrong then the problem will not get fixed. Carbohydrates can be thought of in the same way. The body uses carbohydrates for energy production. If the body is denied the necessary carbohydrates for energy needs we will start to feel light headed and weak. More carbohydrates will be needed by the body to fill the energy stores of the body. I prefer to use energy in, energy out.
I think the average diet should consist of 50% carbohydrates, 25% protein, and 25% fats. These percentages will need to change as we exercise, get sick, or when there is damage to body tissue. The average water intake for men should be 3.5 liters and 2.5 liters for women. As we exercise this will need to be increased to account for sweat and use by the body. Some vitamins and minerals can be toxic in the body if taken in excess amounts. A good vitamin and mineral supplement can be used if we do not get a good variety of the macronutrients in our diet and will contain the proper amounts to round out the recommended daily amounts required by the body.
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Grosvenor, M., & Smolin, L. (2010). Visualizing nutrition: Everyday choices. Hoboken, NJ: Wiley ;.