Everything you never wanted to know about artificial sweeteners

Your diet soda might just be worse than a regular one.

There are a lot of myths about artificial sweeteners. The main one is that they’re actually better for you than regular sugar. Low-calorie sweeteners have been around for decades now, and we’re finally at a point where we’ve studied them enough to understand roughly how they work and what effect they have on our bodies.

A new study presented at the 2018 Experimental Biology meeting has re-raised all these issues and also re-confirmed what researchers have been thinking for years: artificial sweeteners might actually cause obesity, not prevent it.

We’ll get more into that issue in a moment, but first let’s back up a bit because despite how long we’ve had diet versions of our favorite soft drinks, plenty of people still aren’t clear on the facts. Misunderstandings left over from the early days are still widespread. For example…

Erm… is that whole cancer thing true?

Let’s get this one out of the way. While it is true that some rodent studies found increased rates of certain kinds of cancer, like leukemia, after eating artificial sweeteners, subsequent testing has shown that you don’t need to worry about getting cancer from your diet soda. You’d have to regularly consume astronomical doses of the stuff. On the other hand, we do know that obesity is a major risk factor for many kinds of cancer, so maybe focus on that instead of sucralose.

So I should pick diet soda over regular to lose weight then, right?

We hate to be that guy, but “well, actually…” a lot of the evidence suggests you’d be better off just trying to cut back on the regular soda. It does seem like having fewer calories should help you lose weight, but studies indicate that weight loss isn’t as simple as calories in versus out. You can trick your tastebuds (sort of) into thinking that aspartame or saccharin is the sugar you crave, but your brain isn’t so simple.

More and more evidence is piling up that suggests the diet drink trend is misguided. Or as one 2008 study on obesity and artificial sweeteners asked in its conclusion: “are [artificial sweeteners] fueling—rather than fighting—the very epidemic they were designed to block?”

A few recent studies suggest that consuming fake sugar actually trains your insulin response to store more fat, not less. Basically when you consume real sugar, your tastebuds send an alert to your pancreas that says, “Hey, calories are on the way! Prepare to produce insulin!” The insulin then helps break down the sugars, which either provide immediate energy or go into fat cells for storage. If your body interprets something as sweet when there’s not really sugar on the table, though, it may end up producing that same insulin response. So that diet soda is still prompting your pancreas to store fat, even though you’re not getting to enjoy real sugar—your brain can tell the difference. Artificial sweeteners don’t trigger our reward circuits the same way, so you don’t get the satisfaction of ingesting sugar.

And on top of that, constantly pumping up your insulin response eventually leads it to malfunction. This is essentially what happens in type 2 diabetes, but can occur to a lesser—but still harmful—extent in otherwise healthy people. Eventually your pancreas starts producing too much insulin in response to all food, making you pack on the pounds.

This whole theory is still being tested, but it’s in line with what we observe in people who drink diet beverages: they tend to gain weight. In observational studies you can’t tell whether that’s causative or if it’s just that overweight people tend to drink more diet soda than people at a healthy weight. One clue is that scientists observe what’s known as a dose response. The more artificial sweeteners people consume, the more weight they seem to put on. That suggests it might be the fake sugars themselves that prompt the gain in poundage, not just an association.

Okay, fine. I can totally give this up

There’s some bad news here: it’s hard to quit any kind of sugar, even the artificial stuff. Sugars activate our reward circuits—they give us a hit of feel-good neurochemicals that prompt us to continue craving them. The more sugar you eat, the more you want it.

Since artificial sweeteners don’t satisfy your brain the way real sugar does, though, you don’t sate the craving. You’ll keep hankering after sweet foods and will probably end up eating more calories overall. That adds up to more pounds than you would’ve gained just by eating that cupcake in the first place.

And if you need a more compelling reason, let us all remember the infamous story of the cocaine-addicted rats who preferred sweets over drugs. A 2007 study got a bunch of rats hooked on cocaine and saccharin, then given a choice—cocaine or fake sugar?—most chose the sugar substitute. They were so addicted to saccharin that the researchers wrote they couldn’t give the rats enough cocaine to overcome their desire for a hit of sweetness. The same was true for real sugar.

That’s a powerful addiction, and it shouldn’t be underestimated. You can absolutely quit sugar, real or fake, just like people can absolutely quit cocaine. You just need to take it seriously as an addiction. Don’t think it’ll be easy.

What if I’m just using it to bridge the gap while I quit sugar altogether?

Lots of people switch to diet soda as they’re trying to lose weight, in the hope that the fake stuff will be a satisfactory substitute for real sugar. As we’ve already mentioned, it’s not actually satisfying, and what’s more you’ll probably end up handicapping yourself by trying to trick your brain.

Like people who start exercising, people who drink diet beverages start thinking about how they’re now down on their calorie-count, and whether consciously or subconsciously they often compensate by eating more overall. More calories on average can end up causing more harm to your weight loss goals than the occasional candy bar would have.

You’ll also probably start losing your ability to appreciate more subtle flavors. David Ludwig, a weight-loss specialist at Boston Children’s Hospital, told Harvard Health this about how our tastes can change: “Non-nutritive sweeteners are far more potent than table sugar and high-fructose corn syrup. A miniscule amount produces a sweet taste comparable to that of sugar, without comparable calories. Overstimulation of sugar receptors from frequent use of these hyper-intense sweeteners may limit tolerance for more complex tastes.” That means naturally sweet foods like peaches won’t taste nearly as good, and anything without that hint of sweetness might end up seemingly completely gross.

Ludwig notes too that natural sources of sugar, like fruit, often don’t have the same effect on our insulin responses that candy and cake do. Fiber and other nutrients in fruit help keep your blood sugar levels lower, rather than spiking suddenly, and thus prevents your body from storing all those calories as fat.

So what the heck am I supposed to do when I’m craving sweets!?

Here’s the good news: you can eat real sugar! You should eat real sugar. Just eat it in moderation. Satisfy the craving with a mini candy bar (or heck, even a whole piece of cake). Just try to make your overall eating habits as healthy as possible. Occasional sugar won’t make you pack on the pounds. It’s the constant insulin spikes and misleading artificial sweeteners that get you. Have your cake and eat it too—just don’t eat it every day.