Updated 09 February 2017

Sugary drinks could fuel type 2 diabetes

New research results have confirmed once again that by having just one 350ml sugar-sweetened cold drink a day, you increase the risk of developing type 2 diabetes by 20%.


Research results emerging from the vast European Prospective Investigation into Cancer and Nutrition (Epic) study have confirmed once again that by having just one 350ml sugar-sweetened cold drink a day, you increase the risk of developing type 2 diabetes by 20% (InterAct, 2013).

When we consider how many litres of cheap cold drink are consumed in South Africa every day, it is no surprise that we are sitting on a "volcano of type 2 diabetes" just waiting to erupt.

European study

The Epic Study is probably one of the largest and most representative studies every undertaken to determine what people throughout Europe are eating and drinking and how this affects their health and propensity to develop the so-called diseases of lifestyle (cancer, heart disease and type 2 diabetes).

A sample of more than 11 600 patients with type 2 diabetes and about 15 370 participants without type 2 diabetes, were included in the study.

The reasons for conducting this study to investigate the effect that sweetened cold drinks have on health, include the finding that although initially people living in Europe tended to drink fewer cold drinks than their counterparts in North America, data collected between 1992 and 2000 in the Epic Study indicated that the intake of sweetened cold drinks was apparently on the rise in most European countries, particularly in Northern Europe.

The researchers of this study, therefore, set out to determine the association between the consumption of sweet beverages (juices and nectars, sugar-sweetened cold drinks and artificially sweetened soft drinks) and the incidence of type 2 diabetes in the so-called Epic-InterAct Study (InterAct, 2013).

Dietary intake and other data

Questionnaires appropriate for each participating country were used to determine which category of sweetened beverage the subjects consumed, in what quantities and how often:

  • Juices (either 100% fruit or vegetable juice or concentrate) and nectars (juices with up to 20% added sugar) (Unfortunately the researchers were not able to differentiate between juices and nectars because there is no uniform data available on the nutrient content of these products, which evidently differ greatly in composition throughout Europe)
  • Soft drinks, which included all carbonated, soft or isotonic drinks and diluted syrups (known as "squashes" in SA) sweetened with sugar
  • Soft drinks as above, but sweetened with artificial sweeteners
  • (InterAct, 2013)

The intakes of these beverages by the diabetic and control subjects, were divided into categories ranging from less than one glass per month to one or more glasses per day.

Other data such as lifestyle characteristics (smoking status, alcohol intake, educational level and physical activity), as well as height, weight, waist circumference, BMI and details of chronic health conditions (high blood pressure, high cholesterol, heart disease, and family history of type 2 diabetes), were also collected for each subject and used in the statistical analysis to eliminate bias and remove confounding factors.


The InterAct researchers once again found that people living in Northern countries tended to drink more soft drinks than subjects living in Southern countries in Europe.

When the "low consumers" were compared with the "high consumers", the subjects who drank the most soft drinks were more likely to be men, physically active, less educated, smokers and with a higher waist circumference (an indicator of weight increase) who ate a diet which contained relatively few fruits and vegetables, but was rich in red and processed meat.

Younger women who were physically active, former smokers, and more educated, with a lower BMI and waist circumference, tended to consume more juices and nectars. Low consumers of these types of sweetened beverage were inclined to have more chronic diseases and also to eat less fruit and vegetables, but more meat and sugar-rich foods.

The most significant finding of the InerAct Study was that when all the confounding factors (such as BMI) were eliminated, having one or more glasses of sweetened cold drink a day increased the overall risk of developing type 2 diabetes by 20%.

When the subjects consuming the least sugar-sweetened drinks were compared to those consuming the largest volume of sugar-sweetened drinks, the risk of developing type 2 diabetes rose to a frightening 39%. In other words individuals in this study who had 1 or more sugar-sweetened drinks per day were nearly 40% more likely to develop type 2 diabetes than people who only had 1 sugar-sweetened drink per month (Interact, 2013).

Artificially sweetened beverages

It is interesting to note that the subjects who consumed the most artificially sweetened soft drinks tended to have more chronic disease or family history of diabetes, and have higher BMIs and waist circumference measurements.

I can imagine that the immediate conclusion that readers will jump to is that "artificially sweetened soft drinks cause chronic diseases, obesity and diabetes".

"Not so," say the authors of this in-depth report (InterAct, 2013). They specifically explain that this finding indicates that people who suffer from chronic diseases, such as diabetes and obesity, are more likely to stop drinking sugar-sweetened soft drinks and change to non-nutritive, very-low-energy drinks such as artificially sweetened soft drinks instead.

The reason why the authors are able to state this, is that once they included BMI (as an indicator of overweight or obesity) in their statistical analysis, the risk that consumers of artificially sweetened cold drinks are liable to develop diabetes, was no longer significant. They, therefore, deduced that drinking artificially sweetened cold drinks was fuelled by health problems, not the other way around.

Confirmation of previous results

The InterAct Study has provided even more evidence that there is a link between the intake of liquid sugar in the form of sugar-sweetened beverages (soft, carbonated and isotonic drinks), thus confirming the findings of previous studies.

In 2010, Malik and coworkers from Harvard University in the USA, published a paper on a meta-analysis of studies investigating the association between consumption of sugar-sweetened beverages (soft drinks, fruit drinks, iced tea and energy and vitamin waters) with weight gain and the risk of chronic metabolic diseases (e.g. metabolic syndrome and type 2 diabetes).

These authors concluded that "Higher consumption of sugar-sweetened beverages is associated with increased risk of developing type 2 diabetes or metabolic syndrome." (Malik et al, 2010).

South African implications

The fact that researchers in North America and Europe have shown that drinking sugar-sweetened drinks can have negative effects on health and predispose populations to develop overweight and type 2 diabetes, should also be taken to heart in South Africa.

Most of us are aware of workers on building sites drinking large quantities of cheap sweetened cold drinks to keep hunger at bay and that sugar-sweetened squashes are among the most popular items on local shopping lists, that office workers sip cola drinks all day, that many children’s lunch boxes contain bottles of diluted squash, and that our "Born Frees" are having sweetened cold drinks practically on a daily basis (Feeley at al, 2009).

Such wide-spread excessive intakes of sugar-sweetened beverages endanger the health of our people and fuel not only obesity, but also the type 2 diabetes epidemic. "Think before you drink!" and I am for once not referring to alcohol either!

(References: Feeley A et al. (2009). Fast-food consumption among 17-year-olds in the Birth to Twenty cohort. S Afr Med J, 22(3):118-123; InterAct Consortium (2013). Consumption of sweet beverages and type 2 diabetes incidence in European adults: results from EPIC-InterAct. Diabetologia, 56:1520-1530; Malik VS et al (2010). Sugar-sweetened beverages and the risk of metabolic syndrome and type 2 diabetes: a meta-analysis. Diabetes Care, 33(11):2477-83)


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Dr. May currently works as a fulltime endocrinologist and has been in private practice since 2004. He has a variety of interests, predominantly obesity and diabetes, but also sees patients with osteoporosis, thyroid disorders, men's health disorders, pituitary and adrenal disorders, polycystic ovaries, and disorders of growth. He is a leading member of several obesity and diabetes societies and runs a trial centre for new drugs.

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