1 A balanced diet

1.2.1 Inadequate intake

In the developed world inadequate intake of food, at least in terms of energy, is not common. Nevertheless, in many parts of the world starvation is a huge issue, and it is estimated that tens of millions of people face starvation, and well over 5 million, mainly children, die each year from inadequate nutrient intake. Importantly, lack of particular nutrients impairs our ability to carry out many functions.

Can you suggest any processes that would be impaired by starvation?

Growth, tissue repair and resistance to infection are all adversely affected by inadequate food intake.

Thus, people who are starving, or even those who are apparently eating sufficient quantities of food but do not eat a balanced diet, may be susceptible to a variety of illnesses. It is no coincidence that huge increases in the incidence of diseases such as HIV–AIDS and tuberculosis are seen in countries where food is not plentiful, and many starving children are killed by relatively minor ailments that their better-fed counterparts can withstand.

Illness itself can be a cause of inadequate food intake. We all know that illness is often accompanied by a loss of appetite, and if this condition persists, malnutrition can ensue. Alack of appetite is called anorexia, and, ironically, it can also be caused by medical treatment, and by conditions such as depression, particularly in the elderly. In the UK, anorexia nervosa is sometimes seen. Anorexia nervosa is a condition manifested by an extreme aversion to food. It might be accompanied by bulimia nervosa, a condition in which the individual binges and then gets rid of the excess food by means of vomiting or laxatives. The disorder usually affects females in the period from their teens until their 30s; only some 5% of anorexic individuals are male.

Psychological hypotheses about the causation of anorexia nervosa fall into three broad categories: