Artificial Sweeteners May Help with Weight Loss

Managing body weight can be a confusing and frustrating journey. Check 10 different weight-loss websites and you’ll likely get 10 conflicting recommendations. But one common denominator among weight-loss experts (and influencers) is that too much added sugar is likely to contribute to weight gain. 

Unlike naturally occurring sugar, like the kind found in fruits, vegetables and dairy, added sugar is typically found in ultra-processed foods, including soda, energy drinks, baked goods and candy. It can also sneak into unsuspecting foods, such as pasta sauce and salad dressings. 

To reduce sugar and caloric intake, many people turn to artificial sweeteners, including aspartame, sucralose and sugar alcohols. Aspartame and sucralose are created in a lab. And while commercially-manufactured sugar alcohols are calorie-free carbohydrates designed to be chemically identical to those found naturally in certain fruits, they, too, are created in a lab. 

While some question the safety of artificial sweeteners, the U.S. Food and Drug Administration (FDA) considers all of these artificial sweeteners, plus others on the market, to be generally recognized as safe (GRAS). This means that to date, they’re all supported by science demonstrating their use meets the FDA’s safety standard, and shows a reasonable certainty of no harm to consumers.

For those who turn to products with artificial sweeteners to reduce caloric intake, there is mixed evidence of their effectiveness for weight loss. For example, there is evidence suggesting that regular use of artificial sweeteners may disrupt the gut’s microbiome, causing dysbiosis—overgrowth of potentially harmful bacteria and a reduction in the number of beneficial bacteria. Dysbiosis has been linked with having more difficulty losing weight.

In 2023, the World Health Organization (WHO) issued an advisory recommending against the use of artificial sweeteners (what they refer to as non-sugar sweeteners or NSS) to control body weight and chronic disease. They based their conclusion on a large systematic review with available evidence at the time. 

Researchers from Europe collaborated on a study that challenges the WHO’s current advisory on artificial sweeteners. They published their findings in Nature Metabolism. Let’s break down what they found.

How Was This Study Conducted?

Researchers recruited 341 adult men and women, ages 18 to 65, as well as 38 6- to 12-year-old boys and girls. The adults had BMIs of 25 kg/m² or over, which classifies them as having overweight or obesity. The kids all fell into a BMI category above the 85th percentile for their age. Prior to entering the study, all participants regularly consumed products containing sugar. They were not using weight loss medication, and they had never had weight loss surgery.

Each participant was followed for a year. For the first two months of the study, adults followed a reduced-calorie meal plan. Since weight management is trickier with children because they’re still growing, the goal for them was to maintain their baseline weight. 

Participants were randomly assigned to two groups and were instructed to eat healthy diets without caloric restriction for months three through 12, but with a caveat. Both groups were asked to keep added sugar intake to less than 10% of their total energy intake. One group, however, was allowed to consume foods and drinks containing all commercially available artificial sweeteners, while the other group was not allowed to consume any products containing them.

Researchers were looking at several outcomes. The primary outcomes were body weight and gut microbiota composition. Secondary outcomes were waist-to-hip circumference, body composition and risk factors for diabetes and heart disease, which included blood pressure, blood glucose (including HbA1c) and cholesterol and triglyceride levels. Methods of measurement included blood, stool and urine analyses.

What Did This Study Show?

After statistical analyses were run, researchers found that both groups maintained weight loss after 12 months, with the sugar-substitute group weighing, on average, 1.6 kg—that’s 3.5 pounds—less than those in the other group. While statistically significant, it is reasonable to question whether this difference is clinically meaningful.

Researchers also found that the sugar-substitute group had microbiomes with more bacteria that produce short-chain fatty acids (SCFAs) compared to the group that did not consume artificial sweeteners. SCFAs are byproducts of the fermentation of dietary fiber by gut bacteria. They play crucial roles in energy and immunity.

In addition, the group that consumed artificially-sweetened products exhibited decreases in cholesterol levels at six months and in hip circumference at 12 months. While risk factors for heart disease were improved at six months for the artificial sugar group, these benefits diminished by 12 months.

There are some glaring limitations to this study. First, at least five of the study authors received money and/or work for companies and associations that make products (or are industry associations representing these companies) containing artificial sweeteners, including Nestlé, Unilever, the International Sweeteners Association, the American Beverage Association and other organizations and companies in the food and beverage industry. When researchers have financial connections like this, it’s difficult to trust the data coming from their research. Also, there was a 40% participant dropout rate, shrinking the size of the participant groups by the end of the study. The smaller the study, the weaker the data. The study authors also note that they feel that caloric intake was underreported by participants, including at baseline, which was about 25% lower than their estimated energy needs. They also did not directly measure SCFAs in the gut, which also limits the interpretation of the data. 

How Does This Apply to Real Life?

Aiming for a healthy diet with less than 10% of your calories from sugar, as these participants did, may help with weight loss. While this study suggests that including products with artificial sweeteners results in more weight loss than not including products with artificial sweeteners, there are several major limitations to this study, which makes it difficult to place much stock in it. The study also contradicts some previous research. We’d say the jury is still out on this one, though artificial sweeteners may be helpful for you if you’re struggling to eat less added sugar.

Weight loss aside, despite the FDA’s GRAS designation, the WHO’s position on artificial sweeteners is that they should be avoided. It’s important to point out that just because an ingredient is GRAS today, that doesn’t mean it will be tomorrow. As we learn more about all kinds of foods, research may end up proving a GRAS distinction wrong.

We saw this with brominated vegetable oil. And remember the margarine that was supposed to be healthier than butter? We now know that those ingredients weren’t quite as healthy for us as we hoped.

If you still want to try and lower your added sugar intake, you could opt for smaller amounts of sweeteners like maple syrup and honey. Your body will break down the carbs in these sweeteners the same way it does with sugar, but they can help you avoid leaning too heavily on your sugar shaker for morning coffee or afternoon tea. But remember that some artificially-sweetened snacks or sips can still fit into your routine if you enjoy them in moderation.

If you’re ready to aim for less added sugar and artificial sweeteners and want to lose weight, start with our 7-Day No-Sugar Mediterranean Diet Meal Plan for Weight Loss. Or try our 30-Day No-Sugar High-Protein Meal Plan for Beginners. Whichever one you choose, you’re going to get meals and snacks loaded with satisfying nutrients and amazing flavors, without the sugar buzz or artificial ingredients. 

Our Expert Take

This study suggests that including products with artificial sweeteners may help you maintain modest weight loss and support a healthy gut microbiome by increasing SCFA-producing bacteria. However, the clinical significance of these changes is still unclear and research is mixed. Further, several of the study authors have connections to the food and beverage industry, and some received funding from it. Whether you’re trying to lose weight or not, we recommend avoiding too much added sugar, which can make artificial sweeteners a convenient alternative. While consuming products with artificial sweeteners occasionally probably isn’t harmful, the regular ingestion of them might be. 

If you’re skipping the artificial sweeteners and sticking with sugar, try to follow current recommendations. This means that no more than 10% of your daily calories should be from added sugar. If you’re looking for naturally-sweet recipes, try our No-Sugar-Added Mini Apple Pies, No-Sugar-Added Vegan Oatmeal Cookies or toss together a colorful fruit salad or smoothie bowl.