Chapter 2


Information can also be gathered from household budget surveys. These are often undertaken
for reasons other than collecting information on food consumption, for example to update
cost of living figures. The emphasis is on income and expenditure figures, rather than on
consumption. However, if information is available on prices, preferably collected in the
survey itself, inferences can be made about quantities of food coming in to the household.
How good an approximation this is to overall household food consumption depends on the
importance of purchased food in the overall diet. Box 2.1 above illustrates the differences
that can arise when different survey methods are used.

2.1.3 Individual dietary surveys

Similar methods can be used for collecting food consumption data on an individual basis.
Interview methods based on 24-hour recall, or taking a dietary history can obtain a picture of
the food consumption patterns of individuals in specific groups, and usually have a high co-
operation rate, because they tend not to be a great burden for the participant. They are limited
by the accuracy of the recall and the skills of the interviewer. Recording current food intake
can be done by weighing methods and recording methods. These can be more accurate but
can only be carried out for a short period of time and requires a high level of co-operation
from the participants.

2.2 Patterns of food consumption

As the example given in Chapter 1.2, of changing food demand in China, shows, underlying
many of the changes in trading patterns seen recently in the world are changes in the demand
for food at the national, and household level. These patterns are often systematically linked
with economic variables such as income and may be common to most countries. Figure 2.3
below was prepared from a review of food consumption patterns, as shown by Food Balance
Sheets, for countries at different levels of GNP.

At low levels of income, almost 75% of calories come from starchy staple carbohydrates
such as maize, rice, wheat and tubers. As income rises, the diet becomes more complex.
Intake of fats increases, particularly from animal products, and the proportion of calories
coming from the starchy staple falls to 30%. The proportion of calories coming from
sugars increases, but the relative protein contribution remains relatively constant, though
there is a switch from vegetable to animal sources of protein. Total protein in the diet does
increase, as the total availability of calories increases with a rise in GNP. These figures
look at national changes in food availability, but within countries too there is evidence that
people consume a more varied diet as there income rises and as they become more
urbanised.

This is interesting in itself, and also gives a basis on which to judge the reliability of the
results of different types of food consumption survey. However, it is not a useful way of
predicting food consumption and expenditure behaviour. People buy and consume specific
foods which contain nutrients, not the nutrients as such. Thus to explain individual food
consumption behaviour, analysis must be in terms of commodities.