Question: why do we need to eat?

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  1. Eating brings in nutrients into our bodies which we can then use to repair our cells and continue to grow. The first part of eating is mastication where food is broken down in your mouth using your teeth and saliva into small pieces. The food (now called a blous) moves to your stomach and is digested physically (by your stomach griding it up) and chemically (by the stomach acid). By the time it reaches the small intestine it is mostly liquid and mostly the consistancy of a smoothy. In the small intestine the enzymes break the food down into very simple fats, sugars, amino acids, nucleotides – the building blocks of the cell – and they are absorbed into the blood stream directly from the gut. The nutrients are then passed around the body for use or storage. The remaining muck in the small intestine is passed to the large intestine where water is reabsorbed before the bolus is moved to the rectum and finally anus.
    And that’s the life of a ham sandwich.


  2. Hi Princess,

    I might try a slightly shorter answer. We are really just big chemical reactions, just like trees and all other living things.

    In order to power that chemical reaction, we need consume chemicals. So trees will consumer carbon dioxide and expell oxygen, animals will consume the oxygen and expell the carbon dioxide. It all goes to powering our bodies.

    Without it, the chemical reactions would stop and we would cease to live (even though living is slightly more complicated than that)


  3. We need to eat in order to provide our bodies with the energy to function, and to provide nutrients our bodies require that we do not produce within our bodies. What I find amazing is the energy content of food. I exercise quite a lot and wear a heart rate monitor to see how many kilojoules I burn a day (even a scientist when I exercise). My base metabolic rate is about 7,500 kiojoules per day. In exercise I burn between 4,000 and 8,000 per day. So, my total energy usage is ~11,000 – 15,000 kilojoules per day. If you look at McDonalds food, that corresponds to a frighteningly small volume of food. However, if you eat fruit and vegetables and whole foods, you can eat a lot more. It is quite instructive to do your personal energy budget and look at the energy content of food. Generally we eat way too much for our needs.