Chapter 2


Figure 1.2 Percentage Distribution of Calorie Source by Level of per Caput GNP






 ". i e"o B *p. U-' "'. L "


 C4j- -- X








 S. 10 20 30 40 50 60 70 0 90
 100 90 60 70 60 60 40 30 20 I" -
 Percentage ol tolal clones


Source: Perisse et al., The Effect of Income on the Structure of the Diet, Nutrition Newsletter, 1969.

There have been a number of attempts to categorise food behaviour as income rises.
Engel's Law (derived from studies undertaken on in Belgian mining communities by an
applied economist called Engel) states that as income rises, the proportion of income spent
on food falls (total food expenditure may rise but it decreases in relative importance).
Analysis done recently by Lipton suggests that there are some groups of the population for
whom this may not apply. The ultra-poor, as he refers to them, spend about 80% of their
income on food, and cannot spend any more than this, because they also need to buy fuel,
clothes and other basic needs. When their income rises, they will continue to spend a
similar proportion on food until they come close to satisfying their nutritional needs. He
suggests that if household expenditure data show that 80% of a family's income is
insufficient to provide 80% of their calorie requirements, then the family should be
classified as ultra-poor with a considerable food security problem.

Figure 2.3 showed how starchy staples as a whole declined in relative importance as
income increased. This is a generally observed pattern, often referred to as Bennett's Law.
Figure 2.4 shows how complex that process can be in any given country. Data for Peru
show calories from starchy staples increasing from about 600 calories at low income levels
to just over 1100 calories at high income levels. Consumption of maize and barley fell as
income rose, potato consumption rose and stabilised and the consumption of rice and white
bread increased steadily with income. This is typical of many countries with a number of
starchy staples commonly consumed. There will be evidence of a clear hierarchy in
preference amongst the different staples.


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