Methods.
The investigation was made in the following stages :—
- The total national supplies of the main foodstuffs were estimated,
- To get an idea of the nature of the diet in different sections of the community, the whole population was classified in six groups according to family income, and an estimate based on family budget data was made of the consumption of the various foodstuffs in each of the groups.
- The composition of the average diet of each group was examined, the amounts of each of the constituents present being compared with the amounts required for health.
- The state of health of the country was reviewed to get an idea of the extent to which inadequacy of diet is reflected in poor physique and impaired health.
Standards.
The standard of health adopted is the physiological or ideal, viz., a state of well-being such that no improvement can be effected by a change in the diet. It is based on fundamental physiological principles, and it will not alter with any change either in dietary habits or in average health of the community. In an investigation of this nature the standard by which adequacy of diet is measured obviously determines the degree of inadequacy which will be found. The question of the standard to be used is so important that a section has been devoted to a discussion of it.
The standards of dietary requirements adopted are those of Stiebeling of the Government Bureau of Home Economics, U.S.A. These standards provide a sufficiency, with a safety margin, of all essential dietary constituents.
The standard requirements with which the diets of the different groups are compared are on a per head basis calculated on the requirements of children, adolescents, and adults, male and female, and weighted according to the distribution of these in the total population. Hence the data on food consumption were calculated on a per head basis. The reasons for adopting a per head basis in preference to a per man value basis are given in Appendix I.
Data.
The total food supply of the country was estimated from agricultural statistics, returns of imports and exports and output of manufacturers and processers.
The classification of the population into groups according to income was based on Income Tax statistics, wage statistics and data relating to unemployment, Old Age Pensions and other forms ‘ of social income, combined with a sample investigation of the 1931 Population Census designed to yield information as to the sizes of families and the ratio of earners to dependants in different occupation groups.
The estimates of the distribution of the total food supply between the different groups were based on the data from family budgets.
Details of the data and method of treatment are given in Appendices II-VI.
This is the first attempt which has been made to get a picture of the food position of the country showing the relationship of income, food and health. It was recognised that the data were inadequate and some of the existing data of doubtful accuracy, and that therefore the best that could be done would be to make an approximation to the picture which might be drawn if all the requisite data were available. It is believed, however, that the picture is the most accurate which can be drawn under the circumstances, and that therefore it can serve as a working hypothesis, provided that it is always kept in view that it is only an approximation which will need to be revised from time to time as further information accumulates. If this communication helps to increase interest in the subject and to show the need for further investigation, it will serve a useful purpose.