Postprandial glucose levels have received increasing attention as an important marker of metabolic health, providing information beyond fasting glucose. Repeated, high-amplitude glucose spikes after meals have been associated with oxidative stress and endothelial dysfunction, and glycemic variability has become a useful metric to track. Continuous glucose monitoring (CGM) is particularly useful for capturing these changes because it allows glucose patterns to be observed continuously throughout the day rather than at isolated time points.
Much of the research looking at nutrients that may help blunt postprandial glucose spikes has been conducted in controlled settings, where participants are given a fixed amount of carbohydrate, often a standard glucose or sugar drink, and their glucose response is measured. While these types of studies are useful for understanding whether an intervention can work under controlled conditions, they do not give insight into the effects of everyday behavior, when meal composition, timing, activity, and other factors are constantly changing.
One sweetener that has received increasing interest within this field of study is allulose. Allulose is a rare functional monosaccharide and structural isomer of fructose, also known as D-psicose. It occurs naturally in small amounts in foods such as figs, raisins, and jackfruit and is metabolized differently from conventional sugars. While allulose provides about 70% of the sweetness of sucrose (i.e., table sugar), it contributes very little energy, which has made it an interesting alternative for reducing the glycemic impact of carbohydrate-containing meals. Approximately 70% of ingested allulose is absorbed in the small intestine and enters circulation, but more than 99% of the absorbed fraction is excreted unchanged in the urine. The portion that reaches the colon also appears to undergo relatively little microbial fermentation.
A recent case series published in the Biomedical Journal of Scientific & Technical Research looked at whether these effects could also be observed under free-living conditions using CGM. Fifteen generally healthy adults without diabetes and not taking glucose-lowering medication participated in a six-day alternating-exposure protocol. Participants wore consumer-grade CGMs that measured glucose every five minutes and logged their meals through a tracking platform. On odd-numbered days, participants followed their usual diet without supplementation. On even-numbered days, they consumed three allulose-containing gummies with each main meal (a maximum of 9 gummies per day). Each three-gummy serving provided 5.7 g of allulose, along with 3 g of prebiotic resistant starch and 15 mg of a heat-treated Lactobacillus casei postbiotic.
Because the completeness of the CGM and meal data varied between participants, the investigators used a three-tier classification system and limited the primary analysis to the eight participants who had complete six-day records. This resulted in approximately 17,500 total CGM readings across all included participants, though the primary analysis was limited to the eight Tier 1 participants with complete records.
The researchers evaluated three metrics: 24-hour mean glucose, within-day glycemic variability, and postprandial glucose following breakfast, lunch, and dinner. Among the eight participants included in the primary analysis, postprandial glucose was significantly lower on gummy days in 69% of the 48 meal comparisons, with an average reduction of 6.9 mg/dL (p = 0.006). These reductions were greatest at breakfast and dinner, with mean decreases of 9.1 and 9.8 mg/dL, respectively, while no reliable effect was observed at lunch. Glycemic variability was also significantly lower on gummy days, decreasing by an average of 1.35 mg/dL (p = 0.019). In comparison, 24-hour mean glucose decreased by 1.4 mg/dL, but this difference did not reach statistical significance (p = 0.066). These findings suggest that the gummy was associated with lower postprandial glucose and reduced glycemic variability, while changes in overall 24-hour glucose were more modest.
Several mechanisms have been proposed to explain how allulose influences postprandial glucose. One is inhibition of intestinal α-glucosidase activity, an enzyme that breaks complex carbohydrates into absorbable glucose, which slows how quickly glucose enters circulation after a meal. Allulose may also reduce glucose absorption by competing for intestinal transport, since glucose enters intestinal cells through SGLT1, whereas fructose and allulose share the GLUT5 pathway. It has additionally been shown to affect hormones involved in glucose regulation and satiety, including GLP-1, CCK, and PYY. These mechanisms may help explain why allulose helps blunt the rise of glucose that follows the consumption of a carbohydrate-containing meal.
A number of limitations should be kept in mind when interpreting these results. The sample size was small with no placebo control or blinding, participants followed their usual diets rather than standardized meals, and activity levels and exercise were not standardized across study days. Additionally, the gummy paired allulose with resistant starch and a heat-treated Lactobacillus casei postbiotic, meaning the glucose effects may not be attributable to allulose alone. In terms of tolerability, no gastrointestinal or other adverse effects were reported during the study, consistent with the generally favorable tolerance of allulose at similar amounts.
Overall, this case series provides an interesting look at the potential effects of an allulose-containing gummy on glucose patterns during everyday eating. The reductions in postprandial glucose and glycemic variability are consistent with findings from controlled studies of allulose, while the use of CGM provides a different perspective by capturing glucose responses throughout normal daily routines. However, the findings should be considered preliminary, and larger randomized controlled trials are needed.
Learn more about healthy glucose regulation:
Allulose: A Rare Sugar That Supports Postprandial Glycemic Control and Metabolic Flexibility
Foundations of GLP-1 Support: Nutritional and Lifestyle Strategies for Healthy Glucose Metabolism
Reduced-Carb, High-Protein Diet May Improve Glycemic Variability
By Jesse Martin, MS