We require food to accomplish three things:
1.To provide fuel for our body for energy to accomplish daily activity.
2.To provide the necessary materials for the building or maintenance of body tissue and organs.
3.To provide the substances needed to regulate body functioning and processes.
For good health to be maintained, a daily diet of foods must accomplish the previously mentioned three items. Foods that accomplish one or more of the three functions are called nutrients.
There are six classes of nutrients:
These are the chief source of energy for body functioning and muscle activity. Carbohydrates are necessary for the regulation of protein and fat metabolism. The main carbohydrates found in foods are sugars, starches and fiber. Simple sugars are found in fruits, honey and refined sugar and are easily digested. Starches are more complex and are found in plants, vegetables and grains. These more complex carbohydrates require greater digestive action to be broken down into simple sugars. Fiber, although contributes little to energy needs, is helpful in regulating sugars in the body and aid in intestinal elimination.
All sugars and starches are converted, by the process of digestion, into glucose which is a simple sugar. This simple sugar is used as fuel for the body or is stored in the muscle and liver as glycogen. Once the glycogen storage capacity is filled up, the excess glucose is converted to fat to be used as a reserve source of fuel. Carbohydrates are the primary source of energy and are the most efficient at producing energy.
Fats are lipids and are the most concentrated form of energy from the foods we eat. We also can manufacture fats from the overabundance of carbohydrates. Fats are a secondary source of energy when carbohydrate sources can not meet the demand and also act as carriers for some of the vitamins. There are essential fatty acids that we must ingest because the body can't produce them and are necessary for good health. Fats are composed of saturated, monounsaturated and polyunsaturated fatty acids. Excess saturated fat has been associated with high cholesterol levels. Cholesterol is a fat related substance and is necessary for good health. It is also manufactured by the body. An over abundance of cholesterol however has been linked to cardiovascular problems. Fats should not provide more than 30% of your daily caloric intake.
Protein is considered the primary building material for blood, skin, hair, nails, organs and muscles. Protein is used as a fuel source only when carbohydrate and fat supplies are inadequate. Protein is composed of twenty two amino acids, eight of which the body can not produce and must be ingested. These are called essential amino acids. All amino acids must be present for the body to synthesize protein and develop various protein based tissues of the human body. Protein is also necessary for the formation of hormones, the regulation of various body functions and the manufacture of enzymes. Excessive protein will be converted by the liver and stored as fat.
In general ,the body can not manufacture vitamins and therefore they must be supplied by the diet. They have no energy value but are important as a component to almost all metabolic reactions. Vitamins aid in the development of body structures and help convert fat and carbohydrates into energy. There are two classes of vitamins, fat soluble and water soluble. Fat soluble vitamins include A, D, E, and K. These can be stored in the body and an overabundance can lead to toxic levels. Water soluble vitamins include C, B complex and bioflavanoids.
Minerals occur in the environment and are absorbed up the food chain into plants and animals. All minerals known to be important to human functioning can not be produced by the body and have to be supplied by the human diet. They assist with metabolism, biological reactions, water balance, hormone production, and bone development. Minerals that have high concentrations in the body are called macro-minerals. Those minerals found in minute amounts in the body are called trace-minerals.
Water constitutes of 70% to 80% of the human body. Water helps gives structure and form to the body, it allows an environment necessary for cell metabolism, and provides a way for the body to maintain a stable temperature. All the water outside the body cells is called extracellular fluid. The majority of extracellular fluid is contained in the blood plasma. Water inside the cells is called intracellular fluid and composes the majority of the body's total water weight.
Good Fats and Bad Fats
The Good Fats
Monounsaturated fats (MUFAs) lower total cholesterol and LDL cholesterol (the bad cholesterol) while increasing HDL cholesterol (the good cholesterol). Nuts including peanuts, walnuts, almonds and pistachios, avocado, canola and olive oil are high in MUFAs. MUFAs have also been found to help in weight loss, particularly body fat. Polyunsaturated Fats
Polyunsaturated fats also lower total cholesterol and LDL cholesterol. Seafood like salmon and fish oil, as well as corn, soy, safflower and sunflower oils are high in polyunsaturated fats. Omega 3 fatty acids belong to this group.
The Bad Fats
Saturated fats raise total blood cholesterol as well as LDL cholesterol (the bad cholesterol). Saturated fats are mainly found in animal products such as meat, dairy, eggs and seafood. Some plant foods are also high in saturated fats such as coconut oil, palm oil and palm kernel oil.
Trans fats are invented as scientists began to "hydrogenate" liquid oils so that they can withstand better in food production process and provide a better shelf life. As a result of hydrogenation, trans fatty acids are formed. Trans fatty acids are found in many commercially packaged foods, commercially fried food such as French Fries from some fast food chains, other packaged snacks such as microwaved popcorn as well as in vegetable shortening and hard stick margarine.
What can we do? Avoid using cooking oils that are high in saturated fats and/or trans fats such as coconut oil, palm oil or vegetable shortening. Instead, use oils that are low in saturated fats and high in monounsaturated and polyunsaturated fats such as canola oil, olive oil and flax seed oil. minimize using commercially packaged foods which are high in trans fats. Always read labels to look for trans-fat free alternatives. as saturated fats are found in animals products, use lower-fat version dairy such as 1% or skim milk instead of whole milk. Trim visible fats and skins from meat products.