Keto Sweeteners: Which Are Fine, and the Erythritol Question

Sweeteners are how keto keeps dessert, sweet coffee and the occasional treat on the menu without the sugar. They are useful, and for the most part they let you have sweetness without raising blood sugar or knocking you out of ketosis. But they are not all the same, they are not all problem-free, and one of the most popular has recently picked up a cardiovascular question mark worth taking seriously. Here is the honest rundown.

The main keto sweeteners

The sweeteners you will meet on keto fall into a few groups. The natural non-nutritive ones, stevia and monk fruit, come from plants, add no usable carbohydrate and do not raise blood sugar. The sugar alcohols, chiefly erythritol but also xylitol and the best-avoided maltitol, occur in or are derived from plant sugars and vary a lot in how they behave. The rare sugar allulose is newer, tastes very like sugar, and is barely metabolised. And the older artificial sweeteners, sucralose and aspartame, are intensely sweet synthetics used in tiny amounts. Most of these have little or no effect on blood sugar or ketosis, which is the whole point of using them.

The erythritol question

Erythritol deserves its own section, because it is the workhorse of keto baking and the bulk of most granulated keto sweeteners, and because a 2023 study gave reason for pause. Researchers led by Witkowski, publishing in Nature Medicine, measured blood erythritol in people undergoing cardiac assessment and found that higher levels were associated with a greater three-year risk of major cardiovascular events, meaning heart attack, stroke and death. They reproduced the association across cohorts in the United States and Europe totalling around four thousand people, and then showed in laboratory work that erythritol made platelets more prone to clotting, offering a plausible mechanism.

That sounds alarming, and it is worth weighing rather than either ignoring or panicking over. The important caveats are that this was largely observational, so it shows association rather than proof of cause, and that the body actually makes some erythritol itself, so blood levels are not purely a reflection of what you ate. So it does not prove that the erythritol in your dessert will harm your heart. But it is a genuine signal in a large study, with a believable mechanism, about the single most common keto sweetener, and a similar signal has since appeared for the related sugar alcohol xylitol. A reasonable person might respond by moderating their erythritol rather than pouring it on daily, and by keeping an eye on where the research goes.

The gut effects

Sugar alcohols share another, milder issue: in quantity they can cause bloating, wind and a laxative effect, because they are not fully absorbed and get fermented in the gut. Erythritol is the best tolerated of them, which is part of why it became popular. Maltitol is the worst on both counts, since it also raises blood sugar significantly, so it is the one sugar alcohol genuinely worth avoiding, and it turns up in many cheap “sugar-free” sweets. Xylitol sits in between, and is famously toxic to dogs, so keep it away from pets.

The ones that look cleanest

If you want the least-baggage options, stevia and monk fruit are the safest bets: plant-derived, no effect on blood sugar, no carbohydrate, and no cardiovascular flags of the kind raised for the sugar alcohols. Some people dislike stevia’s slight bitter aftertaste, which monk fruit largely avoids, and the two are often blended. Allulose is the other strong option, tasting and behaving remarkably like sugar in cooking, barely raising blood sugar, and some research even suggests it may modestly help glucose control, though it can cause gut upset in large amounts. Between these, most people can sweeten their keto food without leaning on the sugar alcohols at all.

The point most sweetener articles miss

There is a bigger picture worth naming. For many people, a major prize of keto is that sweet cravings fade and the tyranny of the sweet tooth loosens. Leaning hard on sweeteners, however zero-carb, keeps that craving alive and trains you to expect sweetness in everything. Used as an occasional bridge, to make the transition bearable or to enjoy a genuine treat, sweeteners are fine. Used as a daily crutch in coffee, snacks and dessert, they can quietly hold back one of the diet’s better effects. The aim, over time, is to need them less, not more.

The bottom line

Most keto sweeteners do their job of adding sweetness without sugar, but they are not interchangeable. Stevia, monk fruit and allulose look like the cleanest choices. Erythritol carries a real, if not yet settled, cardiovascular question from 2023 research and is worth moderating rather than overusing, xylitol carries a similar newer signal and is dangerous to dogs, and maltitol is the one to avoid because it raises blood sugar and upsets the gut. Above all, treat sweeteners as an occasional helper rather than a daily habit, so the craving they satisfy has a chance to fade.

This is general information about the ketogenic diet, not medical advice. If you have cardiovascular disease or other health conditions, discuss your diet with a doctor. If you are pregnant, on medication, or managing a condition, seek professional advice before making changes.

Source: Witkowski M, Nemet I, et al. The artificial sweetener erythritol and cardiovascular event risk. Nature Medicine. 2023;29:710-718. Read it here.