Question: why do we need food

Sarah Thomas answered on 17 Jun 2011:

Energy!

Every living thing needs energy. And the sun is the source of all energy on earth. The actual energy we get from food is from the connections between the molecules. When these connections are broken during digestion, energy is released and used by our bodies. Our brain alone accounts for 60% of the bodies energy usage!

On food labels, energy is described as ‘calories’. Foods that give us more energy are starchy foods like pasta and fatty foods like cheese.

Our food also provides the building blocks that our bodies need to grow and repair itself. The main food group required for this is Protein. Protein rich foods are things like meat, beans, and vegetables. Your body is essentially made of protein. Proteins are made of long strings of amino acids. Your body digests protein into the amino acids and then absorbs them. They can then be reassembled to make new proteins that your body needs: eg muscle tissue, new blood vessels, hair, nails etc.

We also need to eat food to get vitamins:

Vitamin A – required for eye sight
Vitamin B – promote growth
Vitamin C – immune system
Vitamin D – needed for the absorption of calcium
Vitamin E – maintains healthy skin
Vitamin K – helps absorb your food

We also need to eat food to get minerals:

Iron – to make haemoglobin
Calcium – for bones and teeth
Sodium and potassium – for the transmission of nerve impulses

There is also a psychological need for food. This accounts for some of the unpleaseant feelings associated with hunger. Our brains know we need food, and so eating makes us satisfied and feel safe and good. Fasting can trigger emotional responses due to the brain trying to protect itself through basic survival instincts.