FOOD GROUPS

=Food Groups= We need to eat food for energy, growth / repair and for certain bodily functions. Aside from water most foods are comprised of one or more of the following food groups: *Carbohydrates *Lipids *Proteins *Vitamins & Minerals =Carbohydrates= [image:http://i.imgur.com/6KkJupt.png?2] Carbohydrates form the largest part of most peoples diets and is their main source of energy. There are three main types of carbohydrates: Sugars, Starch & Fibre Sugar is found in foods such as sweets, fruit & honey. Starch is found in rice, potatoes, bread, pasta etc. Fibre is found mostly in fruit, vegetables and especially cereals (grains). Fibre is the indigestible portion of food, but it plays an important role, helping to move food through the intestines. All carbohydrates are actually made up of sugars. Starch & fibre are actually just sugar polymers (this means they are actually just hundreds or even thousands of sugar molecules stuck together). [image:http://i.imgur.com/WoYlFZc.png?1] [image:http://i.imgur.com/RVHJ6k4.png?1] '''Cellulose''' Cellulose is the most common form of fibre on the planet. It is a major component of plant cells (the cell wall is mainly cellulose). Many herbivores rely on cellulose as a food source even though no mammals can digest it. They rely on bacteria in the gut to help break down (digest) the cellulose for them. =Lipids= [image:http://i.imgur.com/8hb6YiP.png?2] Lipids are very high in energy. They have almost 2.5 times the energy of carbohydrates. They are stored by the body as an energy reserve. Animal lipids are usually fats (solid at room temp) Plant lipids are usually oils (liquid at room temp). Foods rich in lipids are butter, cheese, cream, meat and any foods that been cooked in or contain fats or oils. [image:http://i.imgur.com/h3qg7XQ.png?1] Lipids are comprised of a glycerol molecule & three fatty acids. =Protein= [image:http://i.imgur.com/xJ0Wd7h.png?2] Proteins are the moving, working parts of our cells. We break down (digest) the proteins in our food and use the resulting building blocks (amino acids) to make our own proteins. Protein is needed for the growth and repair of tissues. Foods rich in protein include: meat, eggs, milk, cheese, nuts, etc Proteins are comprised of amino acids that have been joined together into long chains. [image:http://i.imgur.com/CEiJyAw.png] There are 20 different amino acids that we need to make our proteins. Many of these we can actually make ourselves, however some of them we need to obtain from breaking down plant / animal proteins in our diet. These are called the ‘essential amino acids’. ==Vitamins & Minerals== [image:http://i.imgur.com/G5FPO28.png?1] Vitamins and minerals are substances that the body needs relatively small amounts of for various cellular processes. They are not considered a 'macro-nutrient' because they aren't normally a considerable source of energy/ building blocks for growth. They are, however, essential to certain body function and play an important role in health. They are found in a wide variety of foods, but fruits and vegetables are often a particularly important source of many vitamins and minerals.