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- South Africa's growing obesity epidemic won’t be reversed by preaching healthier eating habits and exercise alone; the food industry needs to change.
- Studies from Guatemala, Kenya, and Zambia found that big supermarkets can worsen obesity rates through the sale of typically highly processed, calorie-rich foods.
- Medical doctor David Harrison and dietitian Liezel Engelbrecht explain why asking supermarkets to lower the prices of 10 "good foods" isn't anti-business but pro-health.
Driving through Mpumalanga recently, it was inspiring to see how South Africa’s largest food seller, Shoprite, helps locals to sell fruit and vegetables grown in community gardens in some of the retailer’s outlets.
Making it easier for South Africans to buy fresh produce at affordable prices — and to support them to make a living from growing it — is valuable in getting the country to eat healthier and improve local food security.
But to turn around South Africa’s growing obesity — and stunting — rates, and overweight people's consequent higher chance of developing type 2 diabetes, stroke, cancer and heart disease, we need to do considerably more than this.
Almost half of adult South Africans are overweight or obese, the country's 2023 National Food and Nutrition Survey shows, and 69% of obese adults live in households without enough food. If people don’t have enough types of food to choose from, they end up eating nutritionally poor food.
The World Health Organisation says an adult is obese when their weight-to-height ratio is 30 or more. This ratio, called the body mass index (BMI), is worked out by dividing someone's weight (in kilograms) by the square of their height (in metres).
Although scientists say BMI is not the perfect way to tell if someone has a healthy weight, it’s practical, cheap and widely understood, which researchers say makes it a fairly accurate check on a population level.
But most people don't just become obese because they overeat in general — they often eat too much of the wrong food, such as cheap, highly processed starches (like salty snacks and instant noodles) and sugary drinks.
That's why an obese person who ate too much of the wrong food as a child can be both overweight and short — eating too many processed starches made them ”put on carbs,” but didn’t contain the protein and vitamins they needed to grow tall enough.
This height retardation from poor nutrition is called stunting.
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Good food for good health
Good data on the concurrence of stunting and obesity is hard to come by, but a recent study from Mbombela in Mpumalanga found that 41% of obese children under the age of two were also stunted. And in rural KwaZulu-Natal and the Eastern Cape, 2010 research showed that one in six children younger than five years were both short-for-age and overweight.
Among adults, two-thirds of women and one-third of men have a waist-to-height ratio higher than 0.5, which is regarded as the cut-off above, which increases the risk for conditions such as type 2 diabetes (called a metabolic disease).
(A waist-to-height ratio is different from a weight-to-height ratio, or BMI, and another way to calculate someone’s chances of developing metabolic disease). The National Food and Nutrition Survey findings reveal that people eating the wrong foods is a massive problem in South Africa.
The study found only 58.1% of South African households consume acceptable diets and that most people survive on nutrient-poor foods such as processed cereals, condiments, sugars, oils and fats. Consumption of nutrient-rich foods such as fruits, pulses, nuts, eggs, fish and seafood was far and few between.
Foods are nutrient-rich when they contain a high proportion of nutrients good for your health (such as protein, vitamins, minerals and fibre) compared with the calories they provide, while nutrient-poor foods have more calories but fewer of the vitamins, protein and minerals you need to stay healthy.
(Calories measure how much energy there is in the food you eat; to stay at around the same weight, the calories your body uses should be the same as the amount of calories you eat and drink.) Carbohydrates are an important source of energy but these should be in the form of minimally processed whole-grain cereals, legumes like beans, and root vegetables like sweet potatoes.
Eating minimally processed food preserves their vitamins, minerals and dietary fibre. In addition, people need to eat enough protein, which are the building blocks of cells that help to build the structure of the body and brain.
This is where supermarkets — and the country's 220 000 spaza shops — come in. They stock a wide range of foodstuffs and have the potential to massively increase dietary diversity for poor families — in other words, to make the good food, of which people don’t consume enough, easier to get, and the bad food less attractive to buy.
Rands and responsibilities
Grocery stores should bring down the price for at least one brand of protein-rich food staples like sugar beans, tinned fish, eggs, peanut butter and soured milk (amasi), as a matter of urgency. This is the thinking behind the "ten best-buy" strategy advocated for by the DG Murray Trust and Grow Great zero-stunting campaign.
Based on Competition Commission reports, a reasonable estimate is that such discounting by manufacturers and retailers would cause the cost of the specified basket of goods to drop by 10% to 15%. A matching subsidy by the government would make the buyer’s basket go one-fifth further, helping to close the gap between what households need and what they earn.
Together with their existing VAT-exempt status, the basket price could be two-thirds what the market might dictate. The responsibility of big manufacturers and supermarkets is not only a moral one, but a financial one, too: public funding for social grants, such as child grants and state pensions, is a massive contributor to the revenue of the food retail market in South Africa, equal to 30% of total turnover.
This means that taxpayers effectively subsidise part of the profits of the big supermarket chains like Shoprite, Spar and Pick 'n Pay. The culpability of the big food industry is not limited to indifferent pricing. Studies from Guatemala, Kenya and Zambia have found that big supermarkets can worsen obesity rates through the type of foods they stock — typically highly processed, calorie-rich foods.
This seems to be the case in South Africa, too.
Coming to the table
Data from the 2017 National Income Dynamics Study and Google mapping found that people who live closer to the big grocery stores and fast-food restaurants tend to weigh more than those living further away.
Next time you're in a supermarket, count the number of aisles stocking sugary drinks and cereals, sweets and salty snacks. The food industry will argue that they sell what people buy, but both pricing and advertising shape consumer choices.
We also cannot ignore the significant role of spaza shops in the food industry and the economy as a whole. The informal sector accounts for about 20% of food retail, but employs 2.7 times as many people as supermarkets do.
We need to build on their contribution by finding ways to feed more fresh fruit and vegetables into the supply chains of spaza shops and street hawkers. But the government and business, and in particular the food industry, are slow to come to the table.
Business cannot continue to use the excuse that times are too tough for such measures. If times may be tough for manufacturers and retailers, they should try being consumers. In real terms, the top national grocery chains collectively grew their profits by 20% between 2019 and 2023, at the same time as 20% of households reported inadequate access to food.
And there's a further twist to why it’s so important that we must insist on the active involvement of the food industry and don't merely leave it up to people to eat correctly and exercise (two interventions that research has shown rarely result in people keeping weight off in the long term if not also supported by policy and other solutions).
There is evidence that when babies don't get enough food in their mother’s wombs, they have a greater tendency to become obese later in life.
Eating well starts young
Such babies' bodies adapt by trying to store as much as they can. Their genes get programmed for scarcity, making their metabolism of food different from that of well-nourished babies in the sense that their bodies extract as much nutrition as they can out of any food they get. This fine-tuning of one’s genes in response to the environment is called an epigenetic effect.
In lean times, it is a healthy adaptation for undernourished babies, but it becomes a problem later in life if food becomes more available, and they are likely to put on more weight than those whose mothers were well-nourished during pregnancy.
This tendency to gain weight is made even worse by stressful life circumstances, which overstimulate the system in our bodies that regulates metabolism and stress, called the hypothalamic-pituitary axis.
When this system is overactive, it releases higher levels of a stress hormone called cortisol, which results in fat gathering around your belly. These are some of the reasons why in Western countries, poorer people are more obese than richer people.
In sub-Saharan African countries, including South Africa, wealthier people still tend to weigh more. However, the situation is fast changing, with obesity becoming increasingly common among poorer people in both cities and rural areas.
Lifestyles have changed, and outside of famine situations, most families now have enough money to buy staples like maize meal and rice, but not always enough to buy fruit and vegetables, which can't be stored for long times, like maize meal and rice can.
Children who are fed too many starchy products (which are often also high in fat) put on weight. As they grow up, they will become susceptible to type 2 diabetes and high blood pressure, diseases which drain our health systems' budgets.
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Healthy people, healthy economy
In 2018, the direct medical costs of type 2 diabetes was found to be about R2.7 billion for those diagnosed with it in South Africa. But half of people with diabetes in the country don’t even know they have the condition, which means that the real costs to the fiscus from diabetes-related complications are much higher.
The good news is that the epigenetic effects associated with insufficient food in early childhood can be reversed with healthier eating habits, exercise and regular sleep patterns. However, the responsibility to make the best dietary choices someone can afford can’t rest just with the individual; there is a growing realisation that the food system needs to change.
And this realisation isn't anti-business; it’s pro-health and good for the nation's physical and economic well-being. The 2019 Global Burden of Disease Study estimates that just four commercial products — tobacco, alcohol, ultra-processed food and fossil fuels — are responsible for about a third of the world’s annual 56 million deaths and 41% of deaths from noncommunicable diseases such as diabetes, cancer and heart disease.
Monitoring these industries' commercial practices, the respected journal The Lancet says, "should be a core component of national public health surveillance and a part of global governance efforts for health protection and promotion." As Tedros Adhanom Ghebreyesus, the World Health Organisation's director general, wrote in a Lancet editorial last year:
"Health does not begin in clinics or hospitals any more than justice begins in law courts or peace starts on the battlefield. Rather, health starts with the conditions in which we are born and raised, and in schools, streets, workplaces, homes, markets, water sources, kitchens, and in the very air we breathe."
- David Harrison is chief executive officer and Liezel Engelbrecht is an innovation manager and nutrition specialist at the DG Murray Trust.
This story was produced by the Bhekisisa Centre for Health Journalism. Sign up for the newsletter.
