There has been much debate recently about the amount of protein we need to eat in our diet. Theories such the "The Zone" diet have become very popular, following on from the "Atkins Diet"and others that advocate eating much higher levels of protein.

They recommend cutting back on carbohydrates (grains, fruit, breads) and increasing food high in protein (meat, dairy, eggs, nuts, some grains).

It is true that many people rely on a carbohydrate based diet for nutrition and energy, perhaps too much so. Carbohydrates are basically simple or complex sugars which are broken down in the body for energy. It is one of the most basic biological mechanisms in the body, but the theory of these diets is that carbohydrates become easily stored as fat in the body as they are absorbed very quickly into the body. Proteins, on the other hand, are broken down more slowly and utilized in a different way.

Aside from the relative merits of these theories - and no diet is perfect for all people - it is interesting to know more about protein and the foods in which it is found.

Protein comes from the Greek word "Protos", meaning "first", since protein is the basic material for all living cells. The human body contains about 65% water and 25% protein. Protein is made out of nitrogen-containing molecules called amino acids. There are 25 types of amino acids, which when pieced together make different kinds of protein. Of these 25 there are 8 basic amino acids, from which the remaining 17 can be made. These 8 are called essential amino acids.

There is continual debate as to the amount of protein necessary for good health. The World Health Organization estimates we need 4.5% of total calorie intake from protein, while the US National Research Council regards 8% as adequate for most people. Other estimations are that 10% of calorie intake should be from protein, which is about 35 grams (1.5 oz) of protein per day. (The diets mentioned above recommend far higher levels of protein. One critique of them is that it puts much more pressure on the bodies metabolism to digest all the protein, wasting the bodies energy.)

So, which are the best protein rich foods to eat. This question has to be answered by looking both at the quality and quantity of protein found in various foods, along with the other nutritional constituents in the food. For example, a lamb chop provides 25% of total calories as protein and 75% as fat, much of which is saturated fat. In soy beans however, over 50% of calorie intake is protein, the rest being useful complex carbohydrates. This is why soy based food is good for vegetarians.

Grains are commonly thought to be just carbohydrates but in fact they contain protein as well. One of the most complete grains with very high quality of protein is Quinoa, which in fact is technically a fruit. It contains more protein than a grain and more essential fat than fruit. It is also rich in vitamins and minerals and low in fat. Other whole grains are also good sources of protein, as well as certain vegetables such as spinach and brocoli. So it is not just from meat and dairy that we get our protein. It has been commonly thought that grain and vegetable based protein is incomplete by itself, so that it has to be supplemented by animal based protein or by complex mixing of different grains to give a whole protein balance. However, for most people, a varied, balanced diet can supply enough complete protein without going to a lot of trouble.

This is not to advocate a vegetarian diet for all people, but to balance the vegetable and animal sources of protein. It is true however that a high meat diet can create health problems, not the least due to levels of hormones, antibiotics and other toxins found in much meat and fish. It is also true that in western cultures, the reliance on simple sugars for calorie intake (sweets, soft drinks, white bread, sugar etc) has created major health problems. The key is to eat a wide variety of foods, including whole grains such as quinoa, rice and millet; legumes such as lentils and beans, fresh vegetables every day, seeds and nuts, and then animal protein from eggs, dairy products and good meat and fish if desired. More than ever, buying organic meat is important for health reasons mentioned.

Therefore, as has been said endlessly, food should be fresh, and we should emphasize eating a wide variety of foods, especially vegatables, grains, some fruit and then dairy and meat. We shouldn't rely on meat and simple sugars (white bread) as our primary sources of energy. It won't give us the balanced diet we need and it won't give the necessary vitamins, minerals and enzymes vital for health.