Method of analysing family budget and dietary surveys

Family budget surveys presented much information about food consumption, though it had seldom been collected in a form intended for nutritional analysis. Standardization was necessary before subjecting survey material to a computer-assisted process of analysis. Total amounts of food recorded in historical material were assumed to be weights or quantities as bought. Source data were standardized as weights in grams by converting them from imperial weights or quantities. Data originally measured by monetary values were converted by drawing up a table of standard prices for the period of the survey and applying them to give food weights. These were divided by the duration of time over which the food was consumed (i.e. day, week, month or year), and also by the number of persons in the household. Expressing the results per head may be criticized, but since the recommended daily intakes of energy and nutrients in the United Kingdom for children of age 7 and over were broadly the same as for any adult in a sedentary life, the artificial ‘man-value’ scales commonly used in interwar analyses were rejected. R. A. McCance and E. M. Widdowson's The Composition of Foods, 3rd edn (1960) provided the database for the analysis. Foods were analysed as raw weights if there was no wastage in their preparation but wastage allowances as given in McCance and Widdowson were deducted. Otherwise, cooked values of foods were used; but raw foods were used when possible to avoid variation in cooking practices. Any foods fortified, such as bread and margarine, were replaced by equivalent quantities of flour and butter. If composition varied, as with different cuts of meat, qualities were assigned to foods which accorded with contemporary evidence.

Food intake per head per day was given by a food category programme which sorted foods into ten groups: flour, bread, potatoes, sugar, fats, meat, vegetables, fruit, milk and fish. The nutrient analysis programme expressed the diet as energy value, protein, fat, carbohydrate, sucrose and various minerals, particularly calcium and iron. Vitamins were not included in the nutrient analysis since it was concluded that problems of stability and losses in storage and preparation of foods would make the results meaningless.