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  • The WHO says sugar substitutes will not help with weight loss or diet-related diseases.
  • Evidence from randomized controlled trials included in the review showed that while non-sugar sweeteners may help people lose weight over the short term, the changes are not sustained.
  • The guidance applies to all people except those with preexisting diabetes.

The World Health Organization recommends against using sugar substitutes to help with weight loss, or to reduce the risk of diet-related diseases such as heart disease and diabetes.

In new guidance released May 15, the global health body said a review of the available evidence suggests that use of non-sugar sweeteners “does not confer any long-term benefit in reducing body fat in adults or children.”

Evidence from randomized controlled trials included in the review showed that while non-sugar sweeteners may help people lose weight over the short term, the changes are not sustained.

The review also suggests that there may be “potential undesirable effects” from long-term use of non-sugar sweeteners, “such as an increased risk of type 2 diabetes, cardiovascular diseases and mortality in adults.”

Non-sugar sweeteners are widely used as an ingredient in beverages and prepackaged foods. Consumers can also add them to food and drinks.

In 2015 the WHO issued guidance on sugar intake, recommending that adults and children reduce their daily intake of added sugars to less than 10% of their total energy intake. Since then, interest in non-sugar sweeteners has increased, the new review said.

“As a registered dietitian-nutritionist in practice for more than 40 years, I can certainly attest to the fact that those consuming diet sodas and using sugar substitutes do not necessarily successfully lose excess weight and/or maintain a healthful weight,” Mindy Haar, assistant dean at New York Institute of Technology’s School of Health Professions, told Healthline.

“This [guidance] is a great move,” Samantha M. Coogan, a registered dietitian and program director of the Didactic Program in Nutrition & Dietetics at the University of Nevada, Las Vegas, told Healthline.

“More often than not, [non-sugar sweeteners] have more side effects than benefits,” she said. For example, “they’re often not well-tolerated in the [gastrointestinal] tract and lead to bloating and diarrhea.”

In addition, many sugar substitutes are hundreds of times sweeter than table sugar. “This potentially leads to other sweetened foods tasting more bland,” said Coogan, “causing people to crave sweeter and sweeter foods for the same satisfaction level.”

The WHO guidance applies to all people except those with preexisting diabetes.

“That does not necessarily mean that [non-sugar sweeteners] do not have any undesirable effects for diabetics,” Abigail Basson, PhD, a registered dietitian and instructor in the School of Medicine at Case Western Reserve University in Cleveland, told Healthline.

“The reason why the guidance excludes diabetics is simply because none of the studies in the review [specifically] included people with diabetes,” she said. “Therefore an assessment could not be made” about the risks to this group.

The review identified 283 studies, including both randomized controlled trials — considered the gold standard for studying therapies and treatments — and observational studies.

While observational studies can indicate an association with an outcome, they cannot show direct cause and effect.

Results from certain randomized trials showed that use of non-sugar sweeteners resulted in lower body weight and body-mass index (BMI), but most of these studies lasted three months or less. Longer-term studies did not show a sustained effect on body weight.

In addition, in randomized trials that compared people who used non-sugar sweeteners to those who consumed nothing, an inactive placebo or water, there was no effect on body weight or BMI.

In addition, observational studies found that higher intake of non-sugar sweeteners was linked to higher BMI and an increased risk of obesity.

Observational studies also showed an increased risk of type 2 diabetes, cardiovascular disease, and death from cardiovascular disease or any cause. There was also an increased risk of bladder cancer, particularly among people who used saccharin.

The findings of the observational studies are of “very low to low certainty,” due to the limitations of this type of study.

The WHO said the recommendation is “conditional” because the link between non-sugar sweeteners and disease outcomes is less certain. The results of the studies might also be complicated by other factors such as the characteristics of the study participants and patterns of sweetener use.

The WHO recommendation applies to artificial and naturally-occurring non-sugar sweeteners, such as acesulfame K, aspartame, advantame, cyclamates, neotame, saccharin, sucralose, stevia and stevia derivatives.

Coogan highlighted that the WHO included not just artificial non-sugar sweeteners in their list, but also naturally-occurring ones such as stevia. “Natural does not necessarily mean healthier,” she said.

Low-calorie sugars and sugar alcohols, such as erythritol, are sugars themselves or derived from them, so they are not considered non-sugar sweeteners. As a result, the new guidance did not review research related to them.

However, a recent study found that erythritol — used to add bulk to or sweeten stevia, monk fruit and other keto-friendly reduced-sugar products — was linked to a higher risk of heart attack, stroke and early death.

In animal experiments, researchers also found that higher erythritol levels were linked to a higher risk of blood clotting.

The authors of this study said the results are concerning because non-sugar sweeteners are often marketed to people with type 2 diabetes, obesity and existing cardiovascular disease — all of whom are at higher risk of future heart attack and stroke.

Basson highlighted that additional research is needed to better understand the long-term effects of non-sugar sweeteners, including in people with certain diseases such as inflammatory bowel disease, high cardiovascular risk and type 2 diabetes.

Retrain your taste buds

Basson said individual preferences for sweetness are influenced by genetic factors. In addition, “regular consumption of [non-sugar sweeteners] may have heightened your sensitivity to sweetness,” she said.

As a result, it can be challenging to adapt to less-sweet tastes, she added, which can affect the enjoyment of certain foods.

Luckily, said Coogan, you can retrain your taste buds by weaning yourself off sugar substitutes and replacing them with “natural sugars found in fruits and vegetables, and with unsweetened beverages.”

However, “individuals should realize that changing habits is a process and doesn’t happen overnight,” said Haar.

Wean yourself off slowly

If you want to cut back on your intake of non-sugar sweeteners, Coogan suggests not going “cold turkey.” Otherwise, you risk falling back into your old pattern.

“The key is to slowly wean yourself off,” she said. “If you can avoid altogether, great. But at the very least, use [non-sugar sweeteners] in moderation.”

For example, this might mean cutting back from three diet sodas a day to two a day, and then to one a day.

“Eventually, you can remove them from your daily routine,” said Coogan. “And then maybe reserve a sweetened beverage only for when you go out to eat.”

Basson said another option is to use unsweetened alternatives to dilute beverages and foods that contain non-sugar sweeteners, increasing the unsweetened amount over time.

For example, add water to a sweetened beverage, mix plain yogurt in with a sweetened version, or add lightly-sweetened granola to your favorite sweeter cereal.

Seek tasty alternatives

If you enjoy sweetened beverages or don’t like the taste of plain water, Coogan recommends “spa water,” which is water infused with your favorite fruits.

“Different fruits have different sugar content,” she said. “so experiment until you find the combo that works best for you.”

Another option is to replace some of your sweetened beverages or desserts with fruit with a high water content, such as watermelon, pineapple or peaches, she said — in moderation, of course.

“[Whole fruits] are also more nutrient-dense,” said Coogan, “since they provide antioxidants, vitamins, and minerals, providing more benefit than a [non-sugar sweetener].”

Haar said “substituting fruit – especially [in summer], with delicious melons and berries available — is one strategy [for reducing use of sweeteners].”

“In the winter, frozen fruit and canned fruit packed in their own juice are both healthful and satisfying,” she added.

In addition, spices and seasonings can be used to add flavor to baked goods, plain yogurt, milk, cereal and other foods without adding non-sugar sweeteners, she said. Some great options are cinnamon, cardamom, nutmeg, vanilla and allspice.

“Dates, raisins, bananas, mashed berries, applesauce and shredded coconut can also provide sweetness to all types of foods,” said Coogan, “and are great thickeners or toppings.”

Check food labels

Sweetened beverages and many processed foods like cookies, cakes, pastries and breakfast cereals tend to be high in added sugars or non-sugar sweeteners. These sweeteners also show up in pre-packaged sauces, dressings and condiments.

Basson recommends checking the ingredient list on packaged foods and beverages to look for non-sugar sweeteners such as aspartame, sucralose or stevia, as well as added sugars such as high fructose corn syrup and cane sugar.

“Opt for whole, minimally processed foods whenever possible,” she said. And when possible, cook your meals at home, she said. This gives you greater control over the ingredients.

In addition, it helps to keep in mind your overall diet quality.

“While reducing added sugars and [non-sugar sweeteners] is advisable, equal attention should be given to promoting a diet that prioritizes whole, unprocessed foods such as fruits, vegetables, lean proteins and whole grains,” said Basson.