Waste on the farm and during distribution and processing is taken into consideration as an element in the food balance sheet. Post-harvest losses in most of the countries are considered to be substantial due to the fact that most of the grain production is retained on the farm so as to provide sufficient quantities to last from one harvest to the next. Farm storage facilities in most of the developing countries are usually primitive and inadequately protected from the natural competitors of man for food. The losses tend to become even more serious in countries where the agricultural products reach the consumers in urban areas after passing through several marketing stages. In fact, one of the major causes of food waste in some developing countries is the lack of adequate marketing systems and organization.
Much food remains unsold because of the imbalances of supply and demand.
This is particularly true of perishable foods, such as fresh fruit and vegetables. To obtain a complete picture, food consumption surveys showing the distribution of the national food supply at various times of the year among different groups of the population should be conducted. In fact, the two sets of data are complementary. There are commodities for which a production estimate could best be based on estimated consumption as obtained from food consumption surveys. On the other hand, there are commodities for which production, trade and utilization statistics could give a better nationwide consumption estimate than the data derived from food consumption surveys.