CHAPTER 1: INTRODUCTION, THE PROBLEM AND STUDY SETTING ............... 1-10
2.3 Aetiology of overweight and obesity
2.3.2 Nutrition Transition
A distinct phenomenon known as the Nutrition Transition (Figure 2.2) has been termed to describe the shift in dietary patterns and physical activity experienced in many developing countries due to urbanisation and enhanced technology. It is considered a major contributing factor to the paradoxical “double burden” of malnutrition noted in developing countries such as South Africa (Kimani-Murage et al 2010), and has been noted in other developing countries such as Kuwait (Moussa, Shaltout, Nkansa-Dwamena, Mourad, AlSheikh, Agha & Galal 1998), China and Chile, where increasing income levels have been associated with obesity and its related co-morbidities in children (Amuna & Zotor 2008). When members of society previously consuming a more traditional diet derived from plant-based foods high in carbohydrate and fibre, and low in fat, move to urban areas seeking employment, their diets adapt to the more “Western” diet profile, typified by high intakes of animal protein, processed foods high in saturated fats and sugar, and low in fibre (Popkin 2003). Black South Africans are more affected by nutrition transition than any other race group within South Africa (Bourne, Lambert & Steyn 2002).
Figure 2.2: Stages of the Nutrition Transition (Popkin 2003)
Several studies spanning a fifty-year period, from the 1940’s to the 1990’s, have considered the impact of urbanisation on the diet of Black Africans in South Africa (Bourne et al 2002;
Bourne, Langenhoven, Steyn, Jooste, Laubscher & van der Vyver 1993; Albertse, Neethling &
de Villiers 1990; Fox 1941 p28). In a study of African income and expenditure in 1940, Fox disclosed the macro- and micronutrient composition of Black African diets, living in urban locations surrounding Johannesburg. Whilst only able to analyse the macronutrient and micronutrient content of food “as purchased”, it was reported that the carbohydrate content of their diet contributed as much as 70% of the total energy consumed, while protein comprised 14% of the total energy consumed, and fat 16% of the total energy of the diet. Calcium intake was 225 mg per day, which was well below the recommended intakes for both adults and children (Fox 1941, p28).
When comparing the dietary intake of the urban black population in Johannesburg in 1940 (Fox 1941, p28) to a study conducted on 983, 15 to 64 year old men and women in the Cape
Peninsula 50 years later (Bourne et al 1993), a clear shift in macronutrient intake was noted. A significant decrease of 10.9% in carbohydrate intake, and a significant increase of 59.7% in dietary fat intake (from a low intake of 16.4% total energy in 1940 to a fat intake of 26.2% total energy in 1990) was observed (Bourne et al 1993). Furthermore, a significant decrease in the intake of plant protein was recorded, with a simultaneous increase in the intake of animal protein (high in saturated fat) (Bourne et al 1993). The population group followed a nutritionally deplete diet, with most individuals failing to meet two thirds of the RDA of several micronutrients.
A study by Walker, Walker & Walker (1992) further reinforced how the composition of the Black African diet has changed over time. In 1989, the diets of elderly rural Black African women were compared to the dietary intakes of a similar group in a nearby rural village twenty years previously. The results showed an increase in their dietary fat intake (fat contributed 24%
of total energy in 1989, compared to 19% of total energy in 1969), and protein (comprising 14% of total energy in 1989, compared to 12% of total energy in 1969), with a respective increase in the consumption of animal and dairy products of 75% and 20%. Fruit and vegetable consumption increased considerably by 40%, but the dietary intake of sugar was triple that of twenty years previously. Significant rises in BMI and cholesterol were noted (Walker et al 1992).
Data from SANHANES-1 (2013) showed a higher fat and sugar intake (23.1% of participants) in urban formal areas compared to urban-informal, rural-formal and rural-informal areas, with only 9.8-15.1% of participants in non-urban formal areas having a high fat intake, and 11.7- 18.2% of participants in non-urban formal areas having a high sugar intake. People living in urban-formal areas were also able to maintain a higher intake of fruit and vegetables (34.5% of participants) compared to people living in urban-informal, rural-formal and rural-informal areas (22.2%, 24.5% and 20.9% respectively) (Shisana et al 2013).
South Africa is one of Coca Cola’s™ largest markets in the world (Chopra, Galbraith &
Darnton-Hill 2002), with South Africans consuming 260 servings (237ml) per person in 2012, compared to the worldwide consumption of 94 servings per person (http://www.statista.com).
Carbonated beverages were found to be the third most frequently consumed food/beverage item by very young urban children aged 12 to 24 months old, after maize meal and tea (Theron et al 2007). Small shops and street vendors are prolific in rural and township areas, where fruit, full cream dairy products, high fat meats, fatty snacks such as potato chips and vetkoek, cakes,
biscuits and cool drinks are the main choices on offer (Steyn & Labadarios 2011; Mosupye &
von Holy 2000), with little salad and vegetables available. Whilst fruit is an acceptable snack, the other foods listed are often fried, high in saturated fat, and low in fibre. With 19% of Black Africans consuming such foods more than twice a week (Steyn & Labadarios 2011) there is a probable deleterious effect on their weight and health status.