When we need energy, we eat. But what exactly is in food
that gives us energy? The answer is macronutrients, which can be broken down into 3 different classes: Carbohydrates, Fats, and Proteins. Each has different uses and is found in different foods.
1) Carbohydrates
Some examples Carbohydrate food sources
We use carbohydrates as a quick energy source, because they can be broken down quickly by our bodies. As a result, carbohydrates have gained fame for being the best pre-game food for runners and other athletes. The carbohydrate glucose is also vital for our nervous system.
Carbohydrates are high-carbon molecules and vary from simple sugars, such as glucose, to more complex starch molecules.
The average western diet has 46% of the total calories coming from carbohydrates. The recommended athlete diet, however, is 60% of total calories. A few healthy foods that are high in carbohydrates are: Breads, Rice, Pasta, and Potatoes.
2) Fats
Although they have a very bad reputation, the right quantities and types of fat (see some example food sources in picture on left) actually play a big role in our bodies. Fats supply us with long term energy. We also use fat for the insulation of our organs.
Fats are made out of glycerol (a simple building block for most lipids) and fatty acids (chains of carbon molecules with various lengths).
38% of total calories come from fat in the average western diet. However, it's recommended that an athlete obtain only 25% of their calories from fat.
The important thing about fats is to know which fats we need to consume. There are several different types of fat; unsaturated fat (liquid at room temperature), saturated fat (solid at room temperature), trans fat, cholesterol, and fatty acids.
Saturated fats, which are found in foods such as red meats, egg yolks, dairy products, and commercial baked goods, (see picture on left) are one of the most unhealthy fats. (This is convenient for vegans because most things with high saturated fat content, they don't eat!) Saturated fats are also one of the major causes of Heart Disease, Diabetes and other major diseases. In fact, you should limit your consumption of saturated fats to less than 10% of the total diet. Some types of unsaturated fats, on the other hand, can actually help to lower the risk of Heart Disease. Foods such as avacados, almonds, pecans, sunflower oil, corn oil, and olive oil are examples of food high in unsaturated fats.
Trans fats come from liquid fats that are turned solid by a process called hydrogenation, which occurs in many commercially processed foods (fast food, packaged snacks, etc). Trans fats are especially harmful and you should consume them only in small quantities.
Cholesterol is actually not as harmful to the body as its reputation may make it seem. There are 2 types of Cholesterol: HDL (high-density lipoprotein) and LDL (low-density lipoprotein). LDL is the Cholesterol that clogs your arteries. HDL is the "good" cholesterol because it transports cholesterol from artery walls to the liver.
Dairy products, red meats, shellfish, etc are high in Cholesterol, but it's actually the high consumption of saturated fats that causes the body to make too much Cholesterol. Fatty Acids (Omega 3,6,9) are very good fats. Fatty acids are thought to help the cardiovascular system and prevent illnesses. Fatty acids are found in foods such as walnuts, avacados, leafy greens, oily fish, sesame seeds, etc.
3) Proteins
Many people think of proteins as muscle-builders. However, this may not necessarily be true, and consumption of high amounts of protein can actually be harmful. Our bodies do use protein for the growth of hair, skin and nails, and also for the production of enzymes and cells.
Proteins are chains of amino acids. There are 22 total amino acids. Eight of these are essential, meaning that our bodies cannot produce them and we need to obtain them from our food.
In the average western diet, 16% of the total calories come from protein. An athlete's recommended diet contains about the same amount: 15%. Some healthy food sources to obtain proteins are meats, nuts, beans, fish, and milk (see picture above). Since most of the high protein sources come from animal products, vegetarians and vegans need to check to make sure they obtain enough protein in their diets.
While we need much high quantities of macronutrients, we also need to make sure we include micronutrients in our diets. Micronutrients are what we call vitamins (such as vitamin A, C, D etc.) and minerals (such as Zinc and Iron). We classify vitamins by whether or not they are water-soluble. Vitamins B, and C, for example, are water soluble, meaning that our bodies cannot store them, and so we must make sure we get enough of them every day. Fat-soluble vitamins such as vitamin A, D, E and K can be stored by our bodies so it's not necessary for us to replenish our supply every single day. We need to be careful that we don't become deficient. For example, a deficiency in Iron can lead to Anemia, and a deficiency in Calcium can lead to Osteoperosis in later life. Although our bodies don't need big quantities of micronutrients, it is possible for us to become deficient. But, it's not time to panic yet. You can obtain many of the needed micronutrients in a healthy daily diet, so often there is really no need to take over-the-counter supplements and pills.
Image Sources:
http://weightlossdietsfree.com/don’t-avoid-carbs-during-diet-carbohydrates-and-dieting/carbohydrate-foods
http://www.hoalian.com/healthy-food/high-protein-foods-for-muscle-building-the-truth-about-high-protein-intakes/
http://www.hulsestrength.com/saturated-fat-deadly-food-demon-healthy-part-natural-diet/
Text Sources:
Word Notes on Carbs, Proteins and Fats (Sports Nutrition Course, Part 1)
http://www.joslin.org/info/diabetes_glossary.html
http://www.helium.com/items/1189351-micronutrients
