1. 1. 4 Nutritional deficiency and excess which form the metabolic enzyme structure of the individual. It is not possible to live for more than 2-3 minutes without oxygen. However, life can continue with­ 1. 1. 5 Social, population and environmental out water for between 2 and 7 days depending influences on nutrition upon the ambient temperature and the amount of exercise being taken. Survival without any food at The reliable provision of food requires an orga­ all, but with water, may be for 60-120 days, nized society. A society that is disorganized depending upon the body stores. Females and through war, epidemics of infections or natural those with considerable subcutaneous fat survive disaster is less able to produce or deliver food for longer than slightly built males. than a well-structured stable society with a suffi­ There are individual responses to nutritional ciency of healthy workers. It is important that deficiency and excess. Though in general weight food is grown which is appropriate for the partic­ increase in association with overall excessive eat­ ular population's social, cultural and religious ing and weight loss is associated with inadequate beliefs. The influences on nutrition (Figure 1. 1) dietary intake. The failure to provide the essential include: amino acids, fats, vitamins and trace elements leads to specific lesions which may progress to • food availability and intake morbidity and death.