Sucralose, acesulfame, aspartame — the artificial sweeteners hiding behind 'sugar-free'

'Sugar-free' looks like a win. Then you read the ingredient list and find these things you can't pronounce.

The four you'll find on almost every shake

Sucralose. Marketed as Splenda. Made by treating sucrose with chlorine compounds. 600 times sweeter than sugar. Heat-stable, cheap, almost universal in protein products.

Acesulfame potassium (ace-K). 200 times sweeter than sugar. Synthesised in a lab from acetoacetic acid. Often blended with sucralose because each one tastes slightly metallic on its own.

Aspartame. The original artificial sweetener. Banned and unbanned across various jurisdictions over the years, currently classified by the WHO as a possible carcinogen. Still legal in most countries. Still widely used.

Stevia extract / steviol glycosides. Sold as the 'natural' alternative. Technically derived from a plant. Practically, the version on your label has been heavily processed through chemical isolation steps — it bears about as much resemblance to the stevia leaf as high-fructose corn syrup does to corn on the cob.

Why brands love them

Three reasons.

One: cost. Synthetic sweeteners are dramatically cheaper than real sugar per unit of sweetness. A pinch sweetens an entire batch.

Two: macros. The big marketing claim is '0g sugar' and 'low calorie.' Artificial sweeteners deliver both because the body can't use them as fuel. You taste sweetness, you don't gain calories, the math on the front of the bottle works.

Three: shelf stability. Real sugar caramelises, browns, ferments. Synthetic sweeteners sit in a bottle for two years and taste exactly the same on day 730 as day one. Convenient for the manufacturer. Less convenient for your gut.

The research case is getting harder to ignore

A 2022 study in Cell found that artificial sweeteners changed the balance of gut bacteria within two weeks of regular use.

A 2023 BMJ review linked long-term aspartame intake to heart health concerns.

The WHO's 2023 guidance recommends against using artificial sweeteners for weight loss, citing limited evidence they work and growing evidence they don't.

Not all of this is settled science. Some of it is. The trajectory of the evidence is consistent: the further we look, the less these compounds look like a harmless substitute.

And then there's the taste

Artificial sweeteners hijack the sweetness receptors. They train the palate to expect a level of sweetness that real food can't deliver. After a few weeks of drinking them daily, normal fruit tastes bland.

That's not a moral problem. It's a flavour problem that compounds over years. Once your sweet baseline is calibrated to sucralose, you're never going back to enjoying real food without effort.

Real sugar, used properly

We use unrefined raw cane sugar. About as much as an apple, less than a glass of orange juice, considerably less than most flavoured yoghurts.

The body recognises it. Insulin responds to it the way it evolved to. The taste is short, soft, caramel-edged — and crucially, it stops. Real sugar doesn't leave the metallic aftertaste that synthetics do.

That's the trade-off we made when we built the recipe. A small amount of real sugar in exchange for not putting your body on the receiving end of a chemistry experiment three times a week.

What to look for on the label

If the front says 'sugar-free,' check the back. If you see sucralose, acesulfame, aspartame, or sugar alcohols ending in '-ol' (erythritol, xylitol, sorbitol), it's not sweetened with food.

A short ingredient list doesn't lie. Look for sugar, honey, or fruit. If a brand can hit a balanced macro profile without resorting to lab-made sweeteners, they probably built the product to be drunk, not just sold.

See the full Grounded ingredient list, or shop the range.