Diet and digestion
Food provides the energy needed by living things. Food undergoes both physical digestion and chemical digestion so that it can be absorbed into the bloodstream.
Carbohydrates and fats are high energy sources. Protein, meanwhile, is needed for growth and repair. Protein deficiency leads to diseases such as kwashiorkor.
The table below summarises the three main nutrients in food, what they are made from, and why they are needed.
|nutrient||made from||main uses|
|carbohydrates||simple sugars such as glucose||high energy source|
|fats||fatty acids and glycerol||high energy source|
|proteins||amino acids||growth and repair|
Proteins are also used as an 'emergency' energy source if the diet has insufficient carbohydrates and fats in it.
A balanced diet will also include nutrients that do not provide energy, such as:
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