Knowledge of basic nutrition is helpful for everyone and catering for a vegetarian is no different in this aspect.  It is reassuring to know that all the nutrients needed for a healthy life can easily be obtained from a vegetarian diet.

The main areas to think about are alternative sources of protein, B12 and iron.  These will be covered in this unit as part of a general overview of nutrition and food groups. 
This unit on nutrition is the underpinning knowledge required in order for you to be able to undertake the "Unit 5 - Menu Planning".  Unit 4 will help you put together a weeks menu which is balanced and varied and not reliant on one food group too heavily such as cheese as the source of calcium and protein, or wheat at the primary source of carbohydrates.

Basic Nutrition Groups
 proteins
 carbohydrates
 fats (including oil)
 vitamins and minerals.
Vegetarians, like everyone, also need fibre and water.

All are equally important to everyones well-being, although they are needed in varying quantities, from about 250g of carbohydrate a day to less than two micrograms of vitamin B12.

Carbohydrate, fat and protein are usually called macro-nutrients and the vitamins and minerals are usually called micro-nutrients.

Most foods contain a mixture of nutrients (there are a few exceptions, like pure salt or sugar) but it is convenient to classify them by the main nutrient they provide.
Meat supplies protein, fat, some B vitamins and minerals (mostly iron, zinc, potassium and phosphorous). Fish, in addition to the above, supplies vitamins A, D, and E, and the mineral iodine. All these nutrients can be easily obtained by vegetarians from other sources, as this unit will show.

Protein

Women need about 45g of protein a day (more if pregnant, lactating or very active), men need about 55g (more if very active).  Good sources of proteins for vegetarians are:

 Nuts: hazels, brazils, almonds, cashews, walnuts, pine kernels etc
 
 Seeds: sesame, pumpkin, sunflower, linseeds.

 Pulses: peas, beans, lentils, peanuts, etc. A single serving of peanuts (30g or 1oz) 7.3g protein or chick peas (200g or 7oz) has  16.0g protein.

 Grains/cereals: wheat (in bread, flour, pasta etc), barley, rye, oats, millet, maize (sweet corn), rice. Single serving of bread (2 slices) has 7.0g protein and muesli (6og or 2 ¼ oz) has 7.7g  protein.

 Soya products: tofu, tempeh, textured vegetable protein, veggie burgers, Soya milk. Single serving of tofu (140g or 5oz) has 10.3g protein and Soya milk (1/2 pint) has 8.2g  protein.

 Dairy products: milk, cheese, yoghurt (butter and cream are very poor sources of protein). Single serving of hard cheese (30g or 1oz) has 6.8g protein.

 Free range eggs. One boiled egg has 7.5g protein.

So you can see it is very easy for vegetarians to get good sources of protein from a well balanced diet. 

Amino acids

You have may have heard that it is necessary to balance the complementary amino acids in a vegetarian diet. This is not as alarming as it sounds. Amino acids are the units from which proteins are made. There are 20 different ones in all. We can make many of them in our bodies by converting other amino acids, but eight cannot be made, they have to be provided in the diet and so they are called essential amino acids.

Single plant foods do not contain all the essential amino acids we need in the right proportions, but when plant foods are mixed together, any deficiency in one is cancelled out by any excess in the other.

Its easy because protein foods are mixed together all the time, whether we are meat-eaters or vegetarians. It is a normal part of the human way of eating. A few examples are beans on toast, muesli, or rice and peas.

It is now known that the body has a pool of amino acids so that if one meal is deficient, it can be made up from the body's own stores. Because of this, it is not necessary to worry about complementing amino acids all the time in a vegetarian diet, as long as the diet is generally varied and well-balanced. Even those foods not considered high in protein are adding some amino acids to this pool.

Carbohydrate

Carbohydrate is our main and most important source of energy, and most of it is provided by plant foods. There are three main types:

 sugars/simple carbohydrates are found in fruit, milk and ordinary table sugar. Refined sources of sugar are best avoided as they provide energy without any associated fibre, vitamins or minerals

 complex carbohydrates or starches- are found in cereals/grains (bread, rice, pasta, oats, barley, millet, buckwheat, rye) and some root vegetables, such as potatoes and parsnips. Wholemeal bread and brown rice are best of all because they contain essential dietary fibre and B vitamins.

 dietary fibre refers to the indigestible part of a carbohydrate food.  Fibre can be found in unrefined or whole grain cereals, fruit (fresh and dried) and vegetables.

The World Health Organization recommends that 50-70% of energy should come from complex carbohydrates.  The exact amount of carbohydrate that you need depends upon your appetite and also your level of activity.

Fats & Oils

Too much fat is bad for us, but a little is necessary to keep our tissues in good repair, for the manufacture of hormones and to act as a carrier for some vitamins. Like proteins, fats are made of smaller units, called fatty acids. Two of these fatty acids, linoleic and linolenic acids, are termed essential fatty acids as they must be provided in the diet. This is no problem as they are widely found in plant foods.

Fats can be either saturated or unsaturated (mono-unsaturated or poly-unsaturated). Vegetable fats, with the exception of palm oil and coconut oil which are saturated, are unsaturated.

Now click here to learn about vitamins & minerals.