Are Diet Drinks Really That Bad For You?

Diet Drinks

Our country is in the midst of a health crisis. The number of people suffering from obesity, diabetes and a slew of other metabolic disorders seems to be going up and up as we speak. The culprit is, of course, sugar. It certainly does not help that most of the food and drinks we consume on a day-to-day basis are needlessly infused with excessive amounts of sugar. 

Rising rates of diabetes and obesity. Data from the CDC (1, 2)

Is there a solution though?

Let’s be honest, cutting down on sugar is tough. I don’t know about you, but I find it hard to imagine a life without the occasional sip of coca cola or root beer. And I can imagine that most others feel the same way. But rather than cut back on sugar, many consumers are instead choosing to supplement their diets with artificial sweeteners. These “fake” sugars are designed to taste just like the real deal, but without the extra calories. Not surprisingly, drinks and foods spiked with these sweeteners have become extremely popular. It is now a widespread belief that artificial sweeteners may be a solution to problems like diabetes or obesity that are associated with excess sugar. 

It is now a widespread belief that artificial sweeteners may be a solution to problems like diabetes or obesity that are associated with excess sugar.

But are they really?

Before I begin, I might as well point out that information and misinformation about this topic is everywhere on the internet. In fact, I encourage you to look up “are artificial sweeteners safe” and see what you get. Did you try it? If so, I’m sure you probably noticed a bunch of conflicting sources. Some say yes, others say no. So what’s it going to be? To figure this out, let’s take a dive into the literature and see what actual researchers have to say. Let’s also break the “are artificial sweeteners safe” question down and make it more specific. How about we look at the effects of artificial sweeteners on weight gain, diabetes and metabolism separately?

Weight Gain

First, weight gain. The fear of putting on the pounds serves as a strong motivation for people to seek alternatives to sugar-sweetened foods and drinks. This begs the question: to what extent do artificial sweeteners influence weight gain?

Numerous reviews have presented more or less conflicting results. Some have indeed found a positive correlation, while others have not. But why the disparity? In a 2013 paper, Mark Pereira argues that the results may be skewed by the fact that most regular consumers of diet drinks are obese themselves. These are people who seek out diets in an attempt to control their weight. So rather than diet drinks causing obesity, it seems to be the other way around. This is known as reverse causality. Studies that account for this factor consequently observe no strong link between the two.

Another concern is that artificial sweeteners might positively influence appetite. The idea is that the body “wants” to make up for the sugar that it didn’t get. So even if they don’t contribute directly to weight gain, it is possible that their influence may be more subtle.

Experiments on animal subjects (i.e. pigs, cows) seem to support this. When fed with artificial sweeteners, their overall food intake compared to controls is higher.

However, a number of studies on human participants have found the opposite. A brief 2012 study by Maersk et al comparing participants who had consumed diet drinks prior to a meal with those who had not found that the latter tended to eat less. This is complemented by another study comparing energy intake in individuals who regularly consumed sweeteners and those who didn’t over a period of ten weeks. The authors of that study, Raben et al, found similar results. So even if they are known to impact animals, we can’t be so quick to say that they’ll have the same effects on humans.

So even if they are known to impact animals, we can’t be so quick to say that they’ll have the same effects on humans.

The specific kind of artificial sweetener may matter too. A study published in 2019 comparing the effects of different sweeteners on weight gain found that they each influence it differently. The participants in the study who were given sucralose and saccharin on average gained about 1.85 and 1.18 kg over a four week period. In contrast, the other sweeteners tested had no significant influence. Therefore, the authors suggest that these artificial sweeteners should be categorized as separate entities due to their potentially differing effects on body weight.

So it’s complicated. But even if some sweeteners may influence weight gain to an extent, the overall consensus is that their effect is more or less negligible. I think most of my diet-drinkers can breathe easy here.


Alright, let’s look at our next topic: diabetes. Individuals who consume excess amounts of sugar in their day-to-day life are at a high risk for developing it. Because of this, many people turn to artificial sweeteners as a form of prevention.

But does it work?

In vitro research has shown that artificial sweeteners can stimulate the secretion of gastro-intestinal peptides (e.g. GLP-1). These molecules play a role in regulating the release of insulin into the bloodstream. Therefore, it’s been suggested that they might contribute to insulin insensitivity.

In light of this, several reviews have indeed found a positive correlation between the sweeteners and diabetes. So should we treat these drinks with caution? Well, not so fast. There’s probably multiple factors at play here. For one, let’s keep in mind that obesity itself is a risk factor for developing diabetes. Since many frequent consumers of diet drinks are obese, it follows that studies failing to account for this factor will observe a positive correlation.

This was pointed out in a meta-analysis by Immamura et al from 2015 comparing the influence of soft drinks, diet drinks and fruit drinks on diabetes. Upon correcting for this factor, the increased risk of developing diabetes from diet drinks (per their study) dropped from 25% to 8%. Likewise, another review conducted by the InterAct consortium in Europe found similar results. Risks decreased from 52% all the way down to 11% when obesity was accounted for. Based on these observations, it doesn’t seem like artificial sweeteners really influence diabetes.

Correcting for the influence that obesity may play in studies investigating the link between artificial sweeteners and diabetes.

Yet there may still be reasons to raise alarm.

In a 2016 study, the researchers Kuk & Brown compared the effects of real and artificial sugars on blood glucose levels in both healthy and overweight adults. They found a connection between aspartame intake and increased glucose intolerance in overweight individuals. This link was not observed in leaner participants. From these results, the authors warn that drinking aspartame may be a risk factor for diabetes in those who are already obese.

So maybe there’s more to this issue than reverse causality. As of now, more research is needed to investigate the more subtle effects of these artificial sweeteners.


In the interim though, I suppose we can say that diet drinks aren’t really all that bad. There is no solid link between them and weight gain or diabetes in most individuals. Many of the misconceptions that surround them, such as the idea that they increase appetite or promote the development of diabetes are largely bunk. Of course though, there are studies that suggest that this issue may be more complicated. Perhaps the impacts artificial sweeteners have on health are more subtle.

Perhaps the impacts artificial sweeteners have on health are more subtle.

Moreover, they might potentially influence other conditions beyond weight and diabetes. I suppose, at the risk of sounding cliche, that the best way to negate any potential issues is to drink responsibly. Problems are less likely to arise from the occasional sip every now and then verses chugging a gallon’s worth of diet everyday.

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