Myth 1: Sugar causes diabetes
This has to be the greatest of all myths about diabetes. Diabetes has been around for thousands of years, and we worked out long ago that it had something to do with excess sugar in the urine. Treatments varied from culture to culture and throughout time, but generally focused on either eating more sugars (to replace what was being lost in the urine) or restricting sugars (to reduce losses in the urine), with varying degrees of success. We now know that the sugar in the urine that is characteristic of diabetes is glucose. We also know that essentially all of the carbohydrate we eat, whether it is from starchy or sugary foods, ends up as glucose.
A recent review of the evidence from large observational studies looked at the intake of total carbohydrates, sugars (glucose, fructose, sucrose and lactose) and starch, and the risk of developing type 2 diabetes. The review found an overall lack of evidence of an association between any of them. However, the evidence from large observational studies shows that diets that have a high average glycaemic index (GI) or glycaemic load (GL) are strongly associated with a risk of type 2 diabetes.
Observational studies also suggest that excessive consumption of sugar-sweetened beverages (more than one to two 355 ml drinks a day) is associated with an increased risk of developing type 2 diabetes. There is further evidence associating diet soft drinks with the risk of developing type 2 diabetes.
Unlike randomised controlled trials, observational studies do not prove causality and so more research is needed to determine if these suspected links are real. It could be, for example, that people who usually drink regular or diet soft drinks do so along with other highly processed foods, such as potato chips (crisps and fries), savoury snacks and pastries, or alcohol (scotch and cola, for example). If so, it is perhaps the overall dietary pattern of highly refined food consumption that’s really to blame.
There is evidence from randomised controlled trials that the best way to reduce the risk of developing type 2 diabetes is to consume 2000 to 2500 less kilojoules each day by eating less fat, particularly reducing saturated fat and increasing dietary fibre. Many people can also reduce their kilojoule intake by reducing their consumption of added sugars.
The bottom line is that sugar itself does not cause diabetes.
Myth 2: People with diabetes should not have sugar
The world’s major diabetes associations (American Diabetes Association, Canadian Diabetes Association, Diabetes Australia and Diabetes UK) are in agreement that sugar-free diets should not be recommended to people living with diabetes. The reasons for this are simple: sugars and starches are all digested, absorbed and metabolised to the sugar glucose. Therefore people with diabetes need to carefully balance the type and amounts of all carbohydrate that they eat and drink each day to ensure their blood glucose levels do not go too high or too low, not simply limit the amount of sugars.
As with most things in life, moderation is the key. People with diabetes, like everyone else, should consume added sugars in moderation — no more than 10% of total energy (less than 55 g) a day for the average adult.
Myth 3: Low-carbohydrate diets are best for people with diabetes
There is evidence that a range of different eating patterns can help people to manage their blood glucose levels in the short to medium term. People consuming low-carbohydrate, low-GI, Mediterranean, vegetarian and high-protein diets for at least 6 months will lower their HbA1c by 0.12 to 0.47 percentage points, with the low-carbohydrate diet providing the 0.12% reduction and the Mediterranean diet providing the 0.47% reduction.
For most people, diabetes is a lifelong condition, and food is one of life’s great pleasures. It is therefore wise to choose an eating pattern that you enjoy, that also helps you manage your diabetes well and that you can live with the rest of your days, and not simply follow the latest dietary trend.
Current scientific evidence indicates that non-nutritive sweeteners are safe to consume in moderate amounts, and that they can be useful for reducing consumption
of added nutritive sweeteners.
Myth 4: Non-nutritive sweeteners are worse than sugar
Non-nutritive or ‘artificial’ sweeteners have been around for over a century, helping people to enjoy sweet foods and drinks without the unwanted kilojoules or carbohydrate that can contribute to weight gain and raise blood glucose levels when consumed in excess. There is very strong evidence that non-nutritive sweeteners do not raise blood glucose levels in the short term, but there is some emerging evidence in animals that they may increase the risk of developing type 2 diabetes. Also, there has been conflicting evidence about the effect of these sweeteners on body weight.
Artificial sweeteners and the risk of diabetes
In late 2014, a study linking the artificial sweeteners aspartame, sucralose and saccharin to the risk of diabetes hit the headlines around the globe. The fact that most of this research was conducted in mice was lost in the reporting. The mice were overfed pure saccharin — the sweetener identified by the research as the most potent of the artificial sweeteners under investigation. The result was that it altered their glucose tolerance and gut bacteria (microbiome).
To put the research into context, saccharin was discovered in 1879 and the diabetes epidemic has only developed around the world over the last few decades. The use of saccharin is decreasing — it is no longer a particularly popular sweetener. Aspartame (which was included in the study, but found to be less potent), stevia and cyclamate are much more widely used. Finally, the rodents were fed around 17 times more saccharin than a typical adult consumes (according to the results of Australia’s most recent sweetener survey).
The results of the research can be considered interesting at best, but they definitely don’t provide convincing evidence that ‘artificial’ sweeteners cause diabetes as the headlines suggested. More research is definitely needed before we can draw that conclusion.
Artificial sweeteners and weight
Recent headlines have suggested that despite the fact that they are very low in kilojoules, using ‘artificial’ sweeteners may actually make you gain weight. A recent systematic review looked at all published randomised controlled trials and observational studies about body weight. This review found that the use of low- and no-calorie sweeteners led to small but statistically significant improvements in body weight, body mass index, fat mass and waist circumference in randomised controlled trials. In observational studies, however, the use of low- and no-calorie sweeteners was not associated with improvements in body weight or fat mass, but was in fact significantly associated with slightly higher body mass index. Overall, the evidence from the randomised controlled trials is more powerful than the evidence from the observational studies.
The bottom line is that current scientific evidence indicates that non-nutritive sweeteners are safe to consume in moderate amounts, and that they can be useful for reducing some people’s consumption of added nutritive sweeteners, helping them to lose weight, provided they do not treat themselves with other highly processed foods and drinks as a reward for avoiding the added sugars.
Whenever you see sensationalist headlines claiming that a particular sweetener causes obesity, diabetes and so on, ask yourself if the research was conducted in humans, and whether you consume the amount of sweetener the participants were fed on a regular basis over a long period of time. If your answer is no, chances are that the research finding does not have any relevance for you. However, if you choose to use an alternative sweetener to help reduce your kilojoule intake or manage your blood glucose levels, do so in moderation (as in all things), and use a variety of non-nutritive sweeteners to reduce the likelihood of excessive consumption of any particular one.