Everyone likes sweets. It’s an evolved response to make us seek energy-dense sugars in the wild and eat as much as possible of it. But we’ve also learned that too much sugar can be bad for you, so we’ve developed a hack: sweets our bodies can’t metabolize. All the taste, none of the calories. Which is quite amazing.

So today, let’s take a look at how we’ve managed to hijack one of the most central drives of any living thing, that of feeding themselves, to give ourselves a whole lot of enjoyment while doing almost no ‘feeding’ at all. One very good example of this is sucralose.

Sugarless sweet

So how exactly do you make something sweet that contains zero calories? The wording here is key: it’s not that sucralose doesn’t have any calories — it’s just that you can’t have them. Not most of them, anyway.

Our bodies obtain energy from food by breaking down the chemical bonds which hold it together. Part of what we eat is excreted through the process of digestion, however, because there’s a limit to what our metabolism can process. Certain bonds are either too energy-poor to warrant processing, or just beyond our metabolism’s ability.

Sucralose starts its life as sucrose (sugar) but is transformed through a chemical process. Three oxygen-hydrogen pairs in the sugar molecule are replaced with chlorine atoms. This tiny change makes sucralose pass unprocessed and unabsorbed through our body, essentially locking away the calories it contains. According to the US Food and Drug Administration (FDA), sucralose is actually 600 times as sweet as sugar, and that it can be used “virtually anywhere sugar is used, including cooking and baking” due to its chemical stability.

While its lack of caloric content makes sucralose useful as a sweetener in ‘diet’ items such as gum, cakes, or sodas, arguably its most important use is for diabetics. Sucralose has no effect on a consumer’s carbohydrate metabolism, insulin secretion, or blood glucose levels, so it can be safely consumed by such individuals without health risks (unlike sugar). Due to its high chemical stability, it can be used for alternatives to a wide range of products. Because it doesn’t actually do much in the body, it’s also safe to use as a sweetener for medicine. The commercial name for sucralose is “Splenda”.

Now do note: sucralose is calorie-free, but in its final form, it still contains some calories. This comes down to the fillers used to give it a sugar-like texture and appearance (usually these additives are maltodextrin or dextrose).

How did we get it?

Sucralose was first discovered in 1976 through a cooperation between Queen Elizabeth College and Tate & Lyle, PLC. Folk wisdom has it that it was actually an accident, as a researcher misread the word ‘test’ for ‘taste’ and actually tasted the compound. Which you should never do lightly in a lab setting.

The FDA approved its use for 15 food categories in 1998 and as a wide-range sweetener back in 1999.

Is it safe?

“Sucralose has been extensively studied and more than 110 safety studies were reviewed by FDA in approving the use of sucralose as a general-purpose sweetener for food,” the FDA explains.

Furthermore, the FDA determined that the acceptable daily intake (ADI) level for sucralose and four other “high-intensity sweeteners” would not be exceeded even by “high consumers”, meaning you’re extremely unlikely to go over this limit. This ADI is the quantity of a substance that is deemed safe even for an individual that would consume it every day over the course of their entire lifetime, and it takes into account pregnant or lactating women.

For sucralose, this ADI is 5 mg/kg of body weight/day, roughly translating to 165 packets per day for your average person.

That being said, there is (still limited) evidence that sucralose can negatively impact the microbial communities living in the gut, at least in mice, leading to increased inflammation in the intestines and liver. This doesn’t necessarily mean that humans will see the same effect (not every biological process translates well between species), but it isn’t the most encouraging finding, either.

Long-term inflammation can promote obesity and other health issues. At the same time, while sucralose is used in ‘diet’ food items, some critics have raised the concern that in some cases it may end up making us put on more weight than regular sugar, as individuals might learn to worry less about their sugar intake and thus consume more calories overall.

Finally, while sucralose doesn’t influence blood sugar levels in the general population, at least one study found that obese people who don’t normally consume artificial sweeteners reacted differently. For them, sucralose consumption did lead to elevated blood sugar and insulin levels. However, I haven’t been able to find any follow-up research on this topic.

One area, at least, where we know that sucralose is hands-down better than regular sugar is tooth health. The bacteria in our mouths have as hard a time processing it as our own bodies, so it does ‘starve them out’ to an extent and limit tooth decay. That doesn’t mean you can chow down on endless sucralose cupcakes and have perfect teeth, there are other ingredients in there that still promote tooth decay and you still need to care for them. But it’s less of an impact than that of regular sugar. Sucralose is often used as a sweetener in toothpaste because of this.

For now, while we don’t have everything tied down, we’re very confident that most people can consume sucralose over the long term without any adverse effects. Still, public health institutions around the world strongly advise that if you believe consumption of such sweeteners affects your health you should stop your intake and talk to a doctor. It pays to be safe.