In terms of sugar substitutes, allulose appears to be the safest and best option available right now. I cannot predict what the scientific research will reveal in 5 or 10 years time.
I personally avoid aspartame/NutraSweet (an excitotoxin like MSG), Splenda/sucralose (genotoxic at higher doses), and monk fruit (because it's almost always bundled with erythritol). If you can find a pure monk fruit sweetener, it's probably okay and likely better than stevia. Allulose tastes like regular sugar and I do not detect any aftertaste although some people can detect a slight aftertaste.
Allulose has been studied for a number of years and to find the older studies, you'll need to search for it by its alternate name, d-psicose. In animal studies, allulose has been shown to trigger the release of natural GLP-1 (i.e. part Ozempic-like effect) which slows down gastric emptying and creates a sense of satiety. It's presumed that this also happens in humans but there exists NO studies to prove this yet.
A 12 week randomized controlled trial of healthy Koreans (doi: 10.3390/nu10020160) published in 2018 showed a dose of 4g allulose, twice daily resulted in a slight decrease in body fat mass and percentage body fat. In another arm of the study, a larger dose of 7g (or ~1.5 tsp) allulose twice per day, resulted in small decreases in these additional parameters: abdominal fat, subcutaneous fat, and BMI.
Allulose can be made from a number of sources but the most common is corn stover or the throw-away parts of the corn plant. I like this particular product because it's certified USDA organic, which hopefully means it is glyphosate-free.
