It seems artificial sweeteners are becoming increasingly popular in the media recently. One “guru” preaches the incredible weight loss effects and benefits of these sugar-free, 0 calorie miracles, the next claims these diabolic compounds are the sole cause of weight gain and obesity.

It’s been quite some time since anything in the industry has sparked this much debate and contradicting viewpoints, so here at the RadLab, I wanted to discuss what the recent evidence has to say about artificial sweeteners and let you know the truth about artificial sweeteners and weight loss.

What are the real effects of artificial sweeteners? Do they cause weight gain, and obesity or weight loss and an opportunity to avoid the negative impacts of sugar? You’ll have to read this article to find out the truth...

Artificial Sweeteners and The Research Behind Them

Artificial sweeteners such as sucralose, aspartame, acesulfame potassium (ace-k) and others are common in diet beverages, foods and sugar alternatives as a compound to capture the sweetness of sugar without any of the calories and other negative attributes.

One of the main reasons artificial sweeteners have sparked so much interest lately is due to recent claims that these sweeteners actually cause fat gain and can lead to obesity. Now, even if that is what you have read, that is already quite an overstatement.

Let’s get one thing out of the way: There is absolutely no research that indicates that any artificial sweeteners cause fat gain. If you disagree with that statement, consider the following...

Not all studies are created equal. In general there are observational studies and there are experimental trials. There are very few experimental trials focused on the effects of artificial sweeteners and weight change. Most of the data comes from observational studies.

This is a huge distinction, because observational studies can not imply causation. In fact observational studies are the most prone to confounding bias’. This means that observational studies can never determine for sure if their correlation is actually the causality, or if it’s simply correlated with another variable. For example, if an analysis shows that use of artificial sweeteners is associated with weight gain, it cannot exclude the possibility that:

  • People who gain weight are more likely to consume artificial sweeteners in the first place.
  • Participants in the study who consume artificial sweeteners may get a false sense of dieting and then feel justified to eat unhealthily, or overeat at other times.
  • Because artificial sweeteners are non-caloric, and non-satiating, participants aren’t just eating excess calories, effectively eliminating the deficit the sweeteners helped achieve.

Those are three potential confounding variables that could be contributing to weight gain, associated with artificial sweeteners that have nothing to do with the metabolic effects of artificial sweeteners themselves.

What’s more concerning about observational studies are not the confounders that you do think of, but rather, the confounding factors you don’t think of. This is the primary reason why randomized control trials (RCTs) provide the highest quality of scientific evidence, because they are less susceptible to confounding biases. As it turns out RCTs tell a much different story.

Randomized Control Trials and Artificial Sweeteners

Surprisingly, there haven’t been very many RCTs on this subject, but in fact, two separate meta-analyses of RCTs showed no correlation with weight gain at all. Instead, they found a relationship with modest weight loss.

Based on these findings, I would infer that artificial sweeteners on their own do not cause any weight gain, but rather the associated factors that are commonly correlated with artificial sweeteners can be involved with weight gain.

Considering the laws of thermodynamics and bodyweight (energy in vs. energy out), generally speaking, you need to consume more calories than you burn to increase body weight. Artificial sweeteners themselves contain no calories so it wouldn’t make sense that they would cause a gain in weight, therefore any weight gain associated with them would have to be coming from other correlated factors.

Artificial Sweeteners and Weight Loss

If you’re the type of person who thinks that simply drinking diet beverages is the exclusive answer to your weight loss goals, then you’re probably in the group that keeps gaining weight just like in those observational studies.

The concept of artificial sweeteners do have a place in weight loss strategies as a tool to reduce total number of calories and also total amount of simple sugars for people who are paying attention to those details. The negative metabolic effects of large quantities of sugar are without question. When compared to a diet already full of sugar, the use of an artificial sweetener as a substitute can help alleviate those negative attributes.

Surprisingly however, the research studies don’t compare the use of artificial sweeteners to sugar, they typically compare it to a placebo. This is a shortcoming in itself because nobody is simply drinking water and thinking to themselves, “if I only added some artificial sweeteners I could lose some weight”.

It is unfair to conclude that artificial sweeteners are responsible for weight gain when compared to sugar if the research isn’t even studying the two concurrently. The addition of artificial sweeteners to diets poses no benefit for weight loss or reduced weight gain without energy restriction. So just like there is no research showing artificial sweeteners cause fat gain, there also is no research showing they cause fat loss themselves either.

In reality they can be used as a valid method to transition off of sugar for those interested in a sensible diet and exercise program.

Any analysis that would compare artificial sweeteners use to the equivalency in sugar would have drastically different results on multiple levels than those using a placebo as a control group.

Consuming real sugar instead of artificial sweeteners can have significantly negative health effects as they have been positively associated with obesity, metabolic syndrome, cardiovascular disease and diabetes.

Whereas artificial sweeteners contain no calories, sugar contains a full 4 calories per gram. With the average juice box or can of soda containing around 40-50g of sugar, that’s an extra 150-200 calories per drink just from sugar alone.

So all things considered, when comparing the consumption of sugar to artificial sweeteners, if you keep the rest of your diet and training the same, you will achieve a greater overall calorie deficit and in that case artificial sweeteners can help you achieve fat loss goals, reducing your total carbohydrate and calorie intake for the day.

The Bottom Line on Artificial Sweeteners and Weight Loss

As it stands, based on the available research today artificial sweeteners show promise in their intended purpose to be used as a healthy alternative to sugar, helping reduce total carbohydrate and calorie intake. When used properly with a sensible diet and exercise routine, sweeteners can be an effective strategy to help aid weight loss while still providing the sweet taste of sugars.

Any associations with artificial sweeteners and weight gain are likely due to correlated factors and confounding variables unable to be addressed in observational studies not the sweeteners themselves.

This being said there is no direct weight loss benefit to adding artificial sweeteners into your diet. So unless you are using them as an alternative to regular sugar consumption, there’s no need to introduce them. Sweeteners aren’t a quick-fix weight-loss trick that are suddenly going to ignite fat burning effects, but they certainly aren’t diabolic compounds designed to make you fat either.

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