Its proponents say sugar isn't responsible for rising levels of obesity, but scientific studies show it plays a key part in over-eating.
People are getting fatter, they are getting sicker, and the world is looking for a culprit. The latest effigy to be burned at the altar of obesity is sugary soft drinks, but sugar proponents deny that sugar is at fault. The multibillion-dollar questions are: Why are people – rich and poor – getting so fat, and what can be done about it?
Last month, the South African National Health Nutrition Examination Survey set alarm bells ringing with the finding that 25% and 40% of women were overweight and obese respectively, and 20% of men were overweight and 12% obese.
The Human Sciences Research Council (HSRC), which undertook the research, warned that "South Africa is heading for a disaster", as the noncommunicable diseases associated with being overweight, such as hypertension, type-two diabetes, cardiovascular diseases, among others, presented an "emerging epidemic".
Unfortunately, although billions of dollars are being spent researching the causes of obesity, and even more on a magic drug that would make the problem go away, it appears that there is no easy answer, considering that the body is such a complex organism and that there are many industry interests at stake.
Soft drinks are the "enemy"
Dr Louise van den Berg, with the University of the Free State's department of nutrition and dietetics, earlier this month told dieticians and the media: "Sugar has been accused of causing weight gain, obesity, metabolic disease, cardiovascular disease, hypertension … [but] there is no evidence that sugar in the diet, aside from sugar-sweetened beverages, is linked to risk factors."
So although sugar is not the enemy, soft drinks are, according to Van den Berg. She referred to a study published in the American Journal of Clinical Nutrition last year in which 48 overweight adults consumed one litre of either sugar-sweetened cola, milk, artificially sweetened cola or water a day for six months. Only the sugar-sweetened cola drinkers increased their body weight and total body fat, despite the fact that milk and the artificially sweetened cola had comparable calories, she said.
"The evidence is against sugar-sweetened beverages, not sugar," she told a conference of the Sugar Association of South Africa earlier this month in Franschhoek.
She pointed to the sugar content of a 500ml bottle of Coca-Cola, which has about 11 teaspoons.
In an editorial in the British Medical Journal in January this year, Walter Willet, a professor and chair at the department of nutrition at the Harvard School of Public Health, and David Ludwig of the New Balance Foundation Obesity Prevention Centre wrote: "Sugar in this form does not induce satiety to the same degree as it does in solid form, which makes over-consumption easier.
"Reducing the amount of sugar consumed in drinks deserves special attention because of the strength of the evidence and the ease with which excessive sugar is consumed in this form."
What does the research say
However, the body of evidence directly linking sugar to obesity remains controversial.
Julia Goedecke, a specialist scientist for the Medical Research Council and part of the University of Cape Town's research unit for exercise science and sports medicine, said: "There is evidence to suggest that the intake of sugar-sweetened beverages is associated with increased risk of obesity in adults and children. The relationship between obesity and the intake of sugar in foods is less compelling, probably due to the difficulty in quantifying nutrient intake accurately."
But she also pointed to a recent study showing a link between obesity and sugar.
A meta-study (a study that combines results from different studies) commissioned by the World Health Organisation and published in the British Medical Journal this year, aimed to "summarise the evidence on the association between intake of dietary sugars and body weight in adults and children".
The study, led by Dr Lisa Te Morenga, who is a research fellow at the departments of human nutrition and medicine at the University of Otago, New Zealand, reviewed 68 studies and found that, when the subjects consumed more added sugars, they gained weight, and they lost weight when they reduced their sugar intake. She called the amount of weight "small, but significant".
The authors concluded: "When considering the rapid weight gain that occurs after an increased intake of sugars, it seems reasonable to conclude that advice relating to sugar intake is a relevant component of a strategy to reduce the high risk of overweight and obesity in most countries". Also, replacing sugar with other carbohydrates did not alter the subjects' weight, they found.
Te Morenga said at the release of the study: "It seems easier to overeat if your diet includes lots of sugary foods and drinks. When you overeat, you gain weight."
Food can make us hungry
But the issue of overeating fits into a larger problem: Are some of the foods we eat making us hungry and thus fat?
Tim Noakes, professor of exercise and sports science at the University of Cape Town, says we first have to understand why people get fat. "They get fat because they're hungry. But what causes hunger? The reality is the food we eat causes hunger."
He advocates a low-carbohydrate diet because "the more refined [the carbohydrates, a group that includes sugars], the more they drive hunger".
Willet and Ludwig wrote: "Many starchy foods, particularly highly processed grains and potato products, have a high glycaemic index, raising blood glucose and insulin more rapidly than an equivalent amount of sucrose."
The World Health Organisation ?recommends that "free sugars" – extra sugar that is consumed or added to food – make up no more than 10% of consumed daily calories.
In research published last year in the open-access journal BMC Public Health, two South African researchers investigated sugar consumption in the country. Nelia Steyn and Norman Temple from the HSRC quote Food and Agriculture Organisation figures from 2007 in which South Africans consume, on average, 84g of sugar a day. That is the equivalent of about 17 teaspoons of sugar. This is less than the United States [185g] and the United Kingdom [99g], but substantially higher than other African countries.
Steyn and Temple's research supports the department of health's sugar recommendation, promulgated in 2002, to "use food and drinks that contain sugar sparingly, and not between meals".
Legislation: clash "between government and industry"
However, Health Minister Aaron Motsoaledi is not oblivious to the problem and recognises that more needs to be done. "There is going to be a clash soon between the government and industry," he told the Mail & Guardian. "We believe it is the type of food we are eating."
He specifically mentions the fast-food industry. "There is a mushrooming of fast food [outlets] in Africa … and fast foods are cheap and more easily accessible than healthy foods."
Motsoaledi recognises the South African National Health Nutrition Examination Survey as "a start".
"It raises more and more questions."
Asked whether South Africa would start channelling funds and attention towards obesity research, he said: "It is definitely an area that is important. We can't be talking about obesity as a pandemic and not have research."
But the question of how to cut down on sugar consumption remains. Many scientists – especially those who say that sugar is "toxic", such a neuroendocrinologist Robert Lustig and British scientist John Yudkin who wrote a book on sugar called Pure, White and Deadly – liken sugar to alcohol and drug abuse.
David Kessler, the former commissioner of the United States Food and Drug Administration, said: "Fifty years ago, the tobacco industry, confronted with the evidence that smoking causes cancer, decided to deny the science and deceive the American public. Now we know that highly palatable foods – [those with] sugar, fat, salt – reinforce and can activate the reward centre of the brain. We quickly became trapped in a vicious cycle of dopamine-fuelled urges when we want food and opioid releases when we eat it."
Are these foods addictive
Dopamine-fuelled urges play a major role in drug and alcohol abuse.
However, David Benson, a professor of psychology at Swansea University in Wales, also the keynote speaker at the Sugar Association conference, warned against conflating liking sugar with serious drug addiction.
"People are using the term in many different senses … you're not addicted to sugar in the same way that you are to heroin or cocaine," he said.
"There is a distinction between wanting and liking," Benson said, adding that wanting involves craving, the desperation to access the substance. "When dealing with addiction, be clear in what you mean … It's not a vague preference."
Regarding dopamine release, Benson said substances or experiences are pleasurable because they release dopamine. Sucrose also releases dopamine, but so do your children, music and jokes "all stimulate the reward mechanism in the brain. They all release dopamine."
Although he focused on the chemical release in the brain, when asked about physical dependence on sugar, he said: "There is no evidence that if you put a rat in a cage with sweetened water, it will become addicted."
But even if these sugar-addled rodents went on a squeaky rampage for lack of sweet treats, the pro-sugar lobby would say that it proves nothing because rats are different to humans and the results are not comparable.
Sarah Wild was a guest of the Sugar Association of South Africa