The food that we eat can be primarily split into two different categories, macro nutrients and micro nutrients. A macro nutrient is a nutrient that provides us with the bulk of our diet. They are what the body needs the most of and therefore need to be consumed every day. The three macro nutrients that our bodies need are carbohydrates, proteins and fats (lipids). Carbohydrates are the main supply of energy to the body, so they are needed for the body to work day to day. Fats also supply energy to the body, but are used as a reserve energy source, as it can be stored well. Fats also provide essential fatty acids for the plasma membranes, and also some hormones. Proteins also supply a small amount of energy, but are mainly needed for supplying amino acids. These amino acids are used for making structural proteins for bone and hair, metabolic proteins for enzymes, communication proteins in some hormones and protective proteins in antibodies.
The rest of the nutrients that our bodies need are therefore classified as micro nutrients. These micro nutrients are only needed in small amounts and are often used for a specific job. There are lots of different micro nutrients, and they include things such as vitamins, minerals, copper and manganese.
There are many things that can happen when we don’t maintain a healthy diet, and it depends on the nutrient we aren't eating or are eating too much of. In general, when you don’t eat enough, you will starve. When people begin to starve, the body slows down its metabolic rate, so that it doesn’t use up as much energy. You therefore feel tired and also loose a large amount of body weight. This is due to fat reserves being used up for energy, and also protein in muscle being used for energy. When you eat too much food, you become obese. You are obese if you are 20% or more over the average weight recommended for your height. There are a variety of diseases that you are of risk from if you are obese. Your blood has a higher concentration of cholesterol and also has a higher pressure. This makes them susceptible to coronary heart disease, and also makes them unable to control their blood sugar levels, so diabetes is a risk. There are a variety of cancers that can be caused by obesity and as the person has a larger body mass then their skeleton can suffer from diseases such as arthritis. Malnutrition of certain nutrients also causes certain specific diseases. A deficiency of vitamin D can lead to rickets, a disease where the bones become weakened, so people (especially children) can become bow-legged. A deficiency in vitamin A can lead to a variety of skin problems, and can also cause night blindness.
As you can see, a healthy diet is very important as it keeps our bodies running the way that they should. Many foods now come with the RDA (Recommended Daily Allowance) of nutrients on the side of their packets. If people follow these, it ensures that their diet is balanced and therefore healthy.
