The WHO says we shouldn’t bother with artificial sweeteners for weight loss or health. Is sugar better?

The World Health Organization (WHO ) advised this week that “nonsugar sweeteners shouldn’t be used to achieve weight control or reduce the risk of noncommunicable disease” such as heart disease and diabetes.

Artificial sweeteners can be either natural or synthetic compounds that are 400 times sweeter than sugar by weight but have no or very little energy. Sugar has four calories per gram. A teaspoon of sugar, then, would contain 85 kilojoules.

In Australia, there are several types of artificial sweeteners. Some sweeteners are synthetic, and others are derived from food sources such as monkfruit or stevia leaf.

What do the WHO’s new guidelines mean for those who switched to artificial sweeteners because of health concerns? Should they go back to sugar instead?

Read more: Food and drinks are getting sweeter. Even if it’s not all sugar, it’s bad for our health.

Promoted for weight loss

As a clinical dietitian who worked in the 90s, I can remember the first time artificial sweeteners appeared in processed food. The sweeteners were promoted as an alternative to sugar in food products, which could lead to weight loss.

A can of soft drink sweetened with sugar contains approximately 500. Theoretically, you could lose about 1kg per week by replacing one sugar-sweetened soft drink can with a can of artificially sweetened soft drink.

This is not true, according to research conducted over the last few decades.

What is the basis of this new advice?

The WHO’s recommendation is based on a systematic review that it has carried out. The WHO’s goal was to provide evidence-based guidelines on the use of artificial sweeteners for weight management and disease prevention.

Weight Management is essential, as obesity increases the risk for diseases like diabetes and certain types of cancer, which are the leading causes of death worldwide.

The WHO systematic review includes data from different types of studies that give us additional information.

• The 50 randomized controlled studies (where scientists make changes to a diet while maintaining everything else constant) were designed to test the effects of the change.
• Ninety-seven of the studies were prospective cohorts (where scientists observe risk factors in large groups of people for a long period and see how they impact an outcome without intervening or making any changes).
• Forty-seven of the studies were case-control (another observational type that compares and follows two groups of people who are otherwise matched, aside from their risk factor).

Randomized controlled studies provide causal data that allows us to state the intervention was responsible for the observed change.

Case-control and prospective cohorts only provide associations or links. We cannot prove that the risk factors caused a change in outcomes, in this case, weight. Other risk factors that scientists may not have considered could be at fault. They can give us great clues, especially if we are unable to do a study because it is unethical or dangerous to administer or refrain from specific treatments.

The WHO review examined different types of research on artificial sweeteners. Unsplash, CC BY

The WHO conducted a systematic review of body fatness, death, and noncommunicable disease.

Randomized controlled trials revealed that those who consumed more artificial sweeteners averaged a slightly lower weight (0.71kg) than those who consumed less or no artificial sweetness.

The cohort studies showed that higher intakes were linked to a higher body mass index (0.14kg/m2) and 76% higher odds of obesity.

According to the prospective cohort studies, there is a 23% higher risk of diabetes type 2 for those who consume more artificially sweetened drinks. The risk of type 2 diabetes increases by 34% if artificial sweeteners are consumed as tabletop items (that consumers add to food and beverages).

Artificial sweeteners have not improved or worsened any of the clinical indicators that are used to monitor diabetes in people, such as insulin or fasting blood glucose levels.

In long-term, prospective observational studies that followed participants on average for 13 years, higher intakes of artificial sugars were linked to an increased risk of type 2 diabetes, cardiovascular disease, and mortality.

Artificial sweeteners did not affect cancer mortality or overall rates.

The observational studies showed that this group was more likely to be obese and have poorer health outcomes.

Is there anything wrong with the review?

Some criticism has been directed at the WHO’s recommendation because randomized controlled studies did show that artificial sweeteners can help you lose weight.

The WHO has stated that its recommendations are based on multiple research designs and not only randomized controlled trials.

The WHO also rated the quality of studies included in the review as “low or very Low Certainty.”