| health information | health living | lifestyle | diet and nutrition

Proteins

What are proteins?
What do proteins do?
Where are proteins found?
How much protein should we eat?
References

What are proteins?

Proteins are essential in everybody's diet. They are complex substances found in many foods and are made up of thousands of small units called amino acids. Proteins contain about four kcalories per gram, but the body prefers to use carbohydrate and fat as energy sources.

What do proteins do?

It is vital that we eat enough protein. Proteins are the building blocks of the body. The different amino acids that make up proteins are important for growth, tissue repair and replacement. Bones, muscles, the walls of hollow organs - in fact almost every part of the body - needs a supply of amino acids in order to keep healthy.

Where are proteins found?

Meat and fish are excellent sources of protein. However, you can also get protein from cereals, dairy products, nuts, lentils, pulses and some vegetables.

The proteins in meat and fish provide all the amino acids the body needs, and in approximately the right proportions. For this reason, they are called "complete proteins".

In contrast, the proteins from plants are called "incomplete proteins" because they do not contain all the amino acids the body needs. In fact, no single plant contains all the amino acids the body needs. However, it is possible to obtain all the amino acids the body needs from a vegetarian diet, provided a good variety of grains, pulses, cereals and vegetables are eaten.

How much protein should we eat?

Experts recommend that each day we should eat roughly 0.75 grams of protein per kilogram of body weight. You can use the table below to act as a guide to your protein requirements.

Weight in stones	Weight in pounds	Weight in kilograms	Min recommended daily intake of protein (grams)
8	112	51	40
9	126	57	43
10	140	63	48
11	154	70	52
12	168	76	57
13	182	83	62
14	196	89	67

From a kcalories point of view, about 15 percent of your total daily kcalories should come from protein.

If our diet is too low in calories (from all food sources) the body will begin to use protein as an energy source. It will take the protein in our muscles to convert into calories. This is not good because when this happens important muscle mass is lost and our bodies become weaker and flabbier. People who are dieting and severely restricting their calorie intake run this risk.

Too much protein, however, should also be avoided as this can cause problems in people who have liver and kidney problems. These waste-removing organs become overloaded and have difficulty in coping. Furthermore if the main sources of protein are meat and dairy products - which can also contain a lot of saturated fat - there is a danger that blood cholesterol levels might increase.