Women need about 45g of protein a day (more if pregnant, lactating or very active), men need about 55g (more if very active). Evidence suggests that excess protein contributes to degenerative diseases. Vegetarians obtain protein from:
Nuts: hazels, brazils, almonds, cashews, walnuts, pine kernels etc.
Seeds: sesame, pumpkin, sunflower, linseeds.
Pulses: peas, beans, lentils, peanuts.
Grains/cereals: wheat (in bread, flour, pasta etc), barley, rye, oats, millet, maize (sweetcorn), rice.
Soya products: tofu, tempeh, textured vegetable protein, veggieburgers, soya milk.
Dairy products: milk, cheese, yoghurt (butter and cream are very poor sources of protein).
Free range eggs.
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 we mix plant foods together, any deficiency in one is cancelled out by any excess in the other. We mix protein foods 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. Adding dairy products or eggs also adds the missing amino acids, eg macaroni cheese, quiche, porridge.
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, we don't have to worry about complementing amino acids all the time, as long as our diet is generally varied and well-balanced. Even those foods not considered high in protein are adding some amino acids to this pool.
(http://www.vegsoc.org/info/basic-nutrition.html)
