Protein: What is it? Why do you need it?

The Body Talks by Judy Cole gives a great explanation of the various food groups and why you need them. I thought it would be useful to share this with everyone since I'm sure most people won't be buying her book but understanding food groups is the key to understanding healthy eating.

What does protein do?

1. Builds new tissue.
Your body is made of protein (your brain, heart, liver, skin, muscles, hair, nails etc) and your cells are constantly dying and being renewed. You need to eat enough protein to enable your body to build new bodily tissue / grow new cells - if you don't then your body will take the protein it needs out of your muscles so you basically cannibalise yourself.

2. Forms hormones.
Hormones need to be constantly created and they control countless functions within the body. A lack of protein can result in mood disorders / depression / infertility and other hormone inbalances.

3. Controls your metabolism.
Metabolism is controlled by hormones, which are built by protein so by not eating enough protein, your metabolism slows down which means that you burn your food off more slowly resulting in possible weight gain.

4. Helps eliminate toxins.
Toxins are created in your body all the time through the food you eat, breathing in pollution, chemicals that you put on your skin and more. These toxins are filtered by the body and excreted but protein is needed by the body to enable it to do this effectively.

5. Helps in digestion.
When you eat protein this triggers the release of hydrochloric acid, when you eat carbohydrates this triggers the release glycogen. Hydrochloric acid works against the glycogen so that your food is digested more slowly. By digesting food slowly, your body receives a slow and steady release of energy instead of a peak of energy followed by a huge dip once the energy is all used up.

Where does protein come from?

Protein is made up of amino acids: 9 essential ones and 13 non-essential ones. The essential ones must be provided by your food. The non-essential ones are produced by the liver itself.

Animal proteins (meat, poultry, fish, eggs and dairy products) contain all 9 essential amino acids.
Pulses and legumes (i.e. lentils, beans) and nuts, grains and seeds contain protein but each item alone does not contain all 9 essential amino acids. Pulses/beans have to be combined with nuts/grains/seeds to get all 9 essential amino acids.

If any single essential amino acid is missing or low then the body can't process the protein properly. This means that the body will start to break down your muscles in order to get the protein it needs to function.

The body needs a regular supply of protein because amino acids can only be stored for a few hours but the body is building new tissue, hormones etc 24 hours a day. The average man will use about 14g of protein every 2-3 hours and the average woman will use about 14g of protein every 3-4 hours. If your body is not getting enough protein to carry out all its functions then it will start to break down your muscles.

If the body is breaking down muscles to get its protein then you will have less muscle mass and therefore a slower metabolic rate which in turn will mean less energy, vitality and health - plus probably weight gain. If you have a high muscle mass then your metabolic rate will increase, you will then naturally burn more calories which means you can eat more because your body is using up the calories you take in and doesn't store them as fat.

Can you have too much protein?

Yes. If you consume too much protein then this can cause calcium loss from your bones as well as an imbalance in potassium levels which is dangerous for the heart.

A high protein diet is not balanced or safe for the body - it is a moderate amount of protein consumed at regular intervals during the day that is vital for your health.

How much protein should I have?

The average woman should have about 80-90 grams of protein per day.
The average man should have about 100-110 grams per day.

Protein should be eaten at every meal so that the body gets the amino acids it needs regularly. It is vital to eat protein for breakfast since your body will have gone 10 hours or so without any food or any protein. If you eat toast and jam for breakfast then you are not giving your body any protein - have egg on toast or add a yoghurt or glass of milk to your breakfast.

Protein should form about 30-40% of every meal. You can judge this on your plate - about 1/3 of your plate should be protein and the rest should be vegetables and starch.

Some examples of the amount of protein in different foods:
28g of meat/poultry/fish has just 7g of usable protein.
1 egg has 7g protein.
1 cup of low-fat milk has 8g protein.
1 cup of plain yoghurt has 12g protein.
28g of cheese has 8-10g protein (depends on the cheese).
1/3 cup of cooked lentils has 6g protein.
1/2 cup of broad beans has 6g protein.
3/4 oz of cashew nuts has 5.7g protein.
2 tbsps of peanut butter has 8g protein.

A day's protein for a woman could include 2 eggs for breakfast, 140g of meat/fish for lunch (or 50g meat + 50g cheese), 140g of meat/fish for dinner plus snacks of a handful of almonds and a babybel cheese.

A day's protein for a man could include 2 eggs and 3 rashers of bacon for breakfast, 170g of meat/fish for lunch (or 75g meat + 50g cheese), 170g of meat/fish for dinner plus snacks of a handful of almonds and a babybel cheese.

All pulses/beans/nuts/seeds contain about 1/3 protein and 2/3 carbohydrate so they should be eaten in moderation (unless you're vegan and they are your only protein source). More about carbohydrates and starch in my next posting though...