Sweeteners and the glycemic index
The glycemic index ranks how fast a carbohydrate raises blood glucose. It explains why table sugar and honey behave one way, and why the high-intensity sweeteners, most sugar alcohols and allulose behave very differently. A plain, sourced guide.
At a glance
What GI and GL mean
Two related measures: the glycemic index rates the quality of a carbohydrate; the glycemic load adjusts for how much of it is in a serving.
The glycemic index (GI) is a number from 0 to 100 that ranks a food by how much it raises blood glucose over the two hours after eating, measured against a reference of pure glucose, which is set at 100. It is built from the response to a 50 gram portion of available carbohydrate. By convention, a GI of 55 or below is low, 56–69 is medium, and 70 or above is high. The concept was introduced in 1981 by David Jenkins and colleagues at the University of Toronto.
The glycemic load (GL) takes the next step: it multiplies a food's GI by the grams of available carbohydrate in an actual serving, then divides by 100. A food can have a high GI but a low GL if a normal portion contains little carbohydrate. GI describes the carbohydrate; GL describes the portion in front of you.
Why most sweeteners aren't on the scale
The glycemic index only applies to available carbohydrate. The high-intensity sweeteners — aspartame, sucralose, acesulfame potassium, saccharin, neotame — and the plant-derived steviol glycosides and monk fruit add sweetness without contributing meaningful carbohydrate, so they have essentially no GI. The FDA notes that high-intensity sweeteners generally do not raise blood sugar. Sugar alcohols and allulose are absorbed differently from sugar, which is why their glycemic impact runs from low to near zero.
Where sweeteners fall
Grouped by glycemic impact. GI values are approximate and vary by source, ripeness and testing method; treat them as ranges, not fixed points. Sweeteners with a page here are linked.
Raise blood glucose — the caloric sugars
These are sugars or syrups, so they carry available carbohydrate and register on the GI scale.
| Sweetener | Approx. GI | Note |
|---|---|---|
| Glucose | 100 | The reference point the scale is built on. |
| Sucrose (table sugar) | ~60–65 | Half glucose, half fructose; the everyday benchmark. |
| High-fructose corn syrup | ~55–65 | Similar to table sugar; the ratio of glucose to fructose is close. |
| Honey | ~45–64 | Varies widely with floral source. |
| Fructose | ~15–25 | Low GI, but handled mainly by the liver — low GI is not the whole story. |
| Agave nectar | ~10–20 | Low GI because it is high in fructose, not because it is sugar-free. |
| Lactose | ~45 | The sugar in milk; less sweet than table sugar. |
Little to no effect
These add sweetness with little or no available carbohydrate, so their effect on blood glucose is small to negligible.
| Sweetener | Glycemic impact | Note |
|---|---|---|
| Allulose | Near zero | Absorbed but largely not metabolized; excreted unchanged. |
| Erythritol | Negligible | Mostly absorbed, then excreted unchanged. |
| Other sugar alcohols | Low (varies) | Xylitol and sorbitol low; maltitol higher than the rest. |
| Stevia · monk fruit | Essentially none | Plant-derived high-intensity sweeteners; no available carbohydrate. |
| Aspartame · sucralose · ace-K · saccharin · neotame | Essentially none | Artificial high-intensity sweeteners; calorie-free or near it. |
The near-zero group, in a little more detail
Allulose and the polyols reach a low glycemic impact by different routes — worth a closer look, framed by what the evidence actually shows.
Allulose. A rare sugar that the body absorbs but largely does not metabolize for energy, excreting most of it unchanged. In controlled human trials, replacing sugar with allulose produced little to no rise in post-meal blood glucose; a systematic review and meta-analysis found significantly lower post-meal glucose with allulose versus control. The FDA labels it at 0.4 kcal/g and excludes it from the Added Sugars line. The WHO's 2023 guidance on non-sugar sweeteners does not apply to allulose, because allulose is classed as a sugar rather than a non-sugar sweetener.
Sugar alcohols. Their glycemic impact is low and varies by polyol — erythritol is close to zero, while maltitol sits higher than the others. The sugar alcohols page covers how they are absorbed.
The glycemic index describes one thing — the blood-glucose response to a carbohydrate — and nothing else about a food. Fructose is the clearest example: a low GI, but still a sugar handled mainly by the liver. The ingredient list, the Added Sugars line and total intake still matter.
Common questions
Do artificial sweeteners raise blood sugar?
Essentially no. High-intensity sweeteners carry no meaningful available carbohydrate, and the FDA notes they generally do not raise blood sugar. The WHO has separately advised against using non-sugar sweeteners for long-term weight control — a different question from their short-term glycemic effect.
Does allulose spike blood sugar?
Controlled trials show little to no rise in post-meal blood glucose when allulose replaces sugar, and a meta-analysis found a significant reduction in post-meal glucose versus control. Its glycemic impact is near zero.
Is a low-GI sweetener automatically better?
Not on its own. GI measures only the blood-glucose response, not calories or overall nutrition. Fructose and agave have a low GI yet are still sugars, and portion size — captured by glycemic load — also matters.
What's the difference between glycemic index and glycemic load?
Glycemic index rates the carbohydrate itself; glycemic load adjusts that figure for the amount in a serving. A food can be high-GI but low-GL if a normal portion contains little carbohydrate.
Selected sources
- Jenkins DJ, Wolever TM, Taylor RH, et al. — "Glycemic index of foods: a physiological basis for carbohydrate exchange." Am J Clin Nutr, 1981 — the paper that introduced the GI.
- University of Sydney / Glycemic Index Foundation — GI methodology and food database.
- US Food & Drug Administration — high-intensity sweeteners generally do not raise blood sugar; allulose labeling at 0.4 kcal/g and exclusion from Added Sugars.
- Izumori K., PLOS ONE (2023) — systematic review and meta-analysis of allulose and post-meal blood glucose in healthy adults.
- World Health Organization — 2023 guideline on the use of non-sugar sweeteners.
See how the sweeteners compare
Glycemic impact is one column among several. See how all twenty-one sweeteners line up on calories, sweetness, glycemic impact and baking — side by side.
Open the comparison hub →