Ask the RCW Dietitian: Artificial Sweeteners

Is it true that artificial sweeteners will keep you from losing weight?

Artificial sweeteners have been on both sides of the weight loss debate. As they moved into our food supply to a greater extent in the 1980’s and 1990’s, they were marketed as a weight loss solution in opposition to consuming sugar. Over the past 10-15 years the shift towards more “natural” food and nutrition philosophies has reduced the enthusiasm towards these products. In July of this year, the 180 degree shift was completed when a large-scale review of research connected intake of artificial sweeteners with weight gain and the associated chronic diseases such as diabetes.

How do we make sense of this? Let’s try.

There are six artificial sweeteners approved for use in the United States, but four are most commonly used: acesulfame K (approved in 1988, 200 times sweeter than sugar), aspartame (approved in 1981, commonly used in diet sodas), saccharin (approved in the 1970’s, 300 times sweeter than sugar), and sucralose (approved in 1998, 600 times sweeter than sugar). Stevia, which has become popular in recent years, is generally considered a “natural” sweetener, but falls under the umbrella category of “non-nutritive sweeteners” that do not contain calories.

That last sentence is important. These sweeteners do not contain calories and therefore cannot yield energy to the body. In a vacuum, they are not capable of causing weight gain. Of course, everything we put in our body has an effect on something else, so might there be other ways these products are connected to weight gain?

Even if these sweeteners cannot “cause” weight gain, they are strongly connected with obesity – that’s still meaningful. The July review on the topic, published in the Canadian Medical Association Journal, covered over 400,000 individuals, including seven randomized controlled trials. The data found meaningful increases in BMI, diabetes, and heart disease connected with increased intake of non-nutritive sweeteners. What else could be to blame for the impact on health?

One question to ask is this: which groups of people would be most likely to use large amounts of these sweeteners? Probably well-intentioned people who are already trying to lose weight or combat weight-related diseases. Even if the sweeteners aren’t the original problem, they don’t appear to be the solution either. When these groups of people are researched, however, the data makes it appear that the use of sweeteners is related to the weight problems, even if it may not be impacting weight at all.

Another way to think about this problem: who is most likely to suffer from obesity? The answer: someone who is already obese. It’s harder to lose weight than it is to avoid gaining in the first place. If that group of people uses more artificial sweeteners, those products look like the culprit.

The “health halo” effect is a factor to consider. Plenty of research has shown that when people eat foods that they consider to be “healthy” or low-calorie, they are likely to compensate by eating larger portions or eating something else “extra” to reward themselves (and negate the benefits in many cases). If people using artificial sweeteners compensate in other ways, there’s no way to tell if the artificial sweeteners directly or indirectly affect body weight.

There is a great deal of speculation about all the ways these sweeteners could affect digestion. Do they affect gut microbes? Possibly. And that could be a really big deal, especially because we still have a lot to learn about how much of an impact the bacteria in our gut have on the rest of our body.

Do they affect insulin response? Probably. It’s hard to measure the effect this may have on hunger, but having reviewed many clients’ food journals I can say anecdotally that those who consume large amounts of artificially-sweetened products tend to snack more, especially on sweet foods.

Do they increase cancer risk? Probably not in the amounts we consume them. There have been select animal studies that have shown increased cancer risk with extremely large intakes of artificial sweeteners (specifically aspartame), but normal intakes in humans (even up to 20 cans of diet soda per day) have not been shown to have an effect.

What’s the takeaway? If you’re comparing them to sugar, artificial sweeteners are still the better choice for weight management. But they don’t come without some question marks in regards to health. Most of the artificial sweeteners we consume are in sweetened beverages, so the best change most people can make is drink water instead. Water is always the best choice for daily hydration. If you need flavor, try fruit infusions. If you are set on having artificially sweetened beverages, be mindful of the impact they may be having on your hunger and eating habits.

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