ZIMSEC O Level Combined Science Notes: Food types and their importance
Carbohydrates-these are energy-rich foods that are largely made up of starch and sugars. They are easily broken down in the body to release energy. They include sadza, rice (both contain high levels of starch), sugar and bread (which contain a lot of sugar).
Carbohydrates are sometimes known as staple foods because they are consumed on a daily basis
Fats and oils-contain more energy than carbohydrates. The body does not usually use them as an immediate source of energy but as an energy store because they are difficult to break down. Examples of foods that contain a lot of fats are cooking oil, meat and dairy products.
Proteins-are used as body building foods. They contain essential molecules which are needed for the growth of new cells, repair damaged and replace dead cells. Foods rich in proteins include eggs, beans, meat and fish.
Fiber-It aids the digestion process by helping move food quickly through the digestive tract.
Fiber is that part of consumed food that is not digested.
It is made up of cellulose (plant fiber)
It is found in foods like carrots, mangoes, cabbage, bananas.
Fruits and vegetables typically contain a lot of fiber
Cooking these foods breaks down the fiber so it is preferable to eat them raw
As already pointed out, fiber aids digestion by ensuring good bowel movement
Vitamins-they allow the body to grow and develop. They also play important roles in bodily functions such as metabolism, immunity and digestion. There are 13 essential vitamins, including vitamins A, C, D, E, and K and B vitamins such as riboflavin and folate.
Metabolism is the working of the body.
It refers to all the chemical processes that occur within the human body in order to sustain life.
Vitamins are required in minute(small) quantities in order for metabolism to occur.
Water is a critical requirement of any balanced diet.
70% of the human body is water.
All the chemical processes within the body take place in solution thus requiring water.
Water is also required for blood, urine, saliva and other juices and fluids produced in the human body.
Water requirements vary from day to day
Water is either taken in as part of food as in liquid form.