Energy-dense foods are relatively cheap sources of energy but typically have a low nutrient density. People with a low income may therefore select a relatively less healthy diet. The high energy density of such diets helps explain the association between obesity and low socioeconomic status. Most studies have been carried out in highly developed countries. We have extended this research to South Africa. Some foods, such as oats, beans, carrots, and apples, are moderately priced sources of energy and are healthy (i.e., they have a low energy density and are nutrient dense). However, such foods are likely to be less desired than many other foods, such as candy, cookies, jam, and chocolate, that have a similar cost (in terms of food energy) but are less healthy. We compared the cost of a typical South African diet with a healthier one. On average, the healthier diet costs 69% more, but this estimate is greatly affected by food choices. For a family whose household income is exceeded by one-third of the population, this increased expenditure represents about 30% of total household income. This could be decreased to about 10% to 15% if a healthy diet is carefully designed. Overall, a healthy diet is unaffordable for most South Africans. This shows the importance of not only educating people in developing countries to the importance of a healthy diet but also explaining how to make such a diet affordable. A more effective strategy is government intervention that manipulates food prices.
Human Sciences Research Council (Wed,) studied this question.