The term “low-Calorie sweetener” describes a group of diverse sweetening agents that have one thing in common: they can deliver the same sweetness as a typical sugar dose, while contributing fewer Calories. You could lump sugar alcohols in here if you want to, but some of the low-Calorie sweeteners are so low in energy that they’re virtually Calorie-free. Examples include stevia, sucralose, aspartame, and many more.
There’s a lot of fear-mongering that seems to be predicated on the assumption that low-Calorie sweeteners are simply too good to be true. If you check out lay press articles, you might run into concerns about cancer risk, impaired glycemic control, out-of-control sugar cravings, paradoxical weight gain, gut microbiome disruption, and so on.
While these various low-Calorie sweeteners are all truly distinct food ingredients that require distinct lines of research, it’s appropriate to collectively summarize the literature by stating that to this point, research has not validated the fear-mongering.
Low-Calorie sweeteners seem to be quite benign within the range of common daily doses, with neutral to positive effects on weight management.
However, if you consider sugar alcohols to be part of this group of sweeteners, it's important to note that high doses of some sugar alcohols can lead to unpleasant gastrointestinal side effects, such as bloating, discomfort, and diarrhea.