On 15th May, 2023 the World Health Organization (WHO) published guidance advising against the use of non-sugar sweeteners (NSS) to control body weight. The WHO guideline refers to evidence that suggests “higher NSS consumption by adults led to lower body weight and body mass index (BMI), compared with not consuming NSS” in the short term but that it was “associated with increased BMI and risk of incident obesity” in the long term. As such the WHO has presented the following recommendation:
WHO suggests that non-sugar sweeteners not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases.
Is this good advice?
Well, for starters, one problem with this advice is that it’s based on equating correlation with causation; something that weakens the reliability of many nutritional recommendations. Thought it’s been said many times before when busting nutrition myths, it bears repeating. Correlation is not causation. Let’s take the example of eating breakfast. Article after article can be found on how breakfast is the most important meal of the day, with research warning that skipping breakfast is associated with overweight and obesity.
Medical, nutritional and exercise practitioners take this to mean that eating breakfast confers benefits on an individual and skipping it somehow impacts our physiology negatively. This is inaccurate. The point is, there is an association with skipping breakfast and overweight/obesity, but in giving recommendations, it’s a leap to suggest skipping breakfast is a cause of overweight/obesity.
Quite the contrary. In fact there is an abundance of evidence to suggest skipping breakfast in the form of time-restricted feeding or intermittent fasting is beneficial, including but not limited to reduced cholesterol and blood pressure and improved metabolic effects. So why is there a negative association in the first place? It could be that people who habitually skip breakfast are those who don’t make healthy food choices in general. This, of course, doesn’t make the skipping of breakfast inherently bad. One can skip breakfast and still make good food choices throughout the day; as often happens with people who deliberately follow time-restricted feeding patterns. All of a sudden, skipping breakfast isn’t a problem and doesn’t lead to overweight/obesity. This correlation-causation misunderstanding is something that should be kept in mind when considering the benefits of non-sugar sweeteners for weight control.
To further examine the WHO’s advice, two points should be clarified. First, research overwhelmingly suggests non-sugar sweeteners to be safe for human consumption. To put things into perspective, aspartame, a sweetener often used in carbonated beverages, has over 100 studies supporting its safety. Second, weight loss is achieved by creating a negative energy balance (calorie deficit); consuming less calories than you burn.
With these two points clarified, the WHO’s advice against the use of non-sugar sweeteners to control bodyweight can be unhelpful. While the WHO’s suggestion for people to “reduce the sweetness of the diet altogether” is understandable, particularly from the perspective of reducing the consumption of highly palatable, calorie dense foods, not all of these foods are sweet. Did someone say pizza? Now, if there is a sugar substitute that is safe for consumption, has little or no calories, thereby helping one to keep their calorie consumption in check, it seems questionable to advise against its use.
Some research even suggests non-sugar sweeteners contribute to sensory-specific satiety, in which consuming food/drink of a specific taste profile (sweet) reduces one’s desire to consume more food/drink of that same taste profile. When’s the last time you wanted something sweet after drinking a bottle of coke zero? The researchers advise: “consumption of LCS [low calorie sweetener] drinks acutely decreases desire for sweet foods, which supports their use in place of sugar-sweetened drinks.“
The WHO justifies their guidance against the use of non-sugar sweeteners with the following statement: “Because free sugars are often found in highly processed foods and beverages with undesirable nutritional profiles, simply replacing free sugars with NSS results means that the overall quality of the diet is largely unaffected.”
This is a problematic justification for several reasons. If non-sugar sweeteners can help people lose weight by reducing their calorie intake, a phenomenon supported by evidence, that is a positive development in itself. Particularly among obese individuals, weight loss has a positive impact on various health markers including glycemic improvement, reduced knee pain, improved sexual function, and reduction in all cause and cardiovascular mortality.
Additionally, using sweeteners and following a healthy diet isn’t mutually exclusive. One can use sweeteners in their coffee or tea, drink no calorie carbonated beverages and still consume other minimally processed unsweetened foods and beverages as advised by the WHO. The use of non-sugar sweeteners can help people make healthy food choices, instead of a common alternative: succumbing to a sweet tooth craving and then bingeing on anything and everything since you’ve ‘fallen off’ your diet. In this instance the WHO is neglecting the importance momentum has in keeping people consistent in making healthy choices. If non-sugar sweeteners can help with dietary compliance, once again it seems misguided to advise against their use.
The WHO mentions that its recommendation is conditional, meaning “the WHO guideline development group is less certain that the desirable consequences of implementing the recommendation outweigh the undesirable consequences or when the anticipated net benefits are very small.” This admission of uncertainty about their conclusion likely won’t be recognized in the deluge of scaremongering that will ensue; something that is particularly prevalent when it comes to discussing non-sugar sweeteners.
Ultimately one of the key pillars to sustainable weight loss is consistency. Fat loss can be difficult and one needs to develop healthy eating habits that will stay with them even after a temporary dieting period is over. That’s why it’s important to enjoy the foods you eat; not only because it helps people stay consistent, but also because for many people food is one of life’s many pleasures. Non-sugar sweeteners can help people enjoy their food and drink without an impulse for overconsumption.
It’s important to acknowledge, however, the difficulty the WHO faces in making its recommendation. To make a generalized statement when nutrition is highly individual to each person is no easy task. Weight control is a multidisciplinary endeavour that requires attention to preferences, psychology, activity levels and many more factors, and so it’s understandable that the WHO concedes it is uncertain about its guidance. Non-sugar sweeteners can be a powerful tool in helping people lose weight and keep it off. From an individual perspective, it’s worth reviewing the WHO’s guidance and considering what role non-sugar sweeteners can play in achieving your weight control objectives.