An article by Healthline states:
1. Artificial sweeteners affect the gut microbiome in mice.
2. The affected gut microbiome raises your blood sugar level.

This topic is important to me, because of my hack to drink milkshakes with fiber supplement pills, which I hope reduces the glycemic response. Assuming the healthiest insulin and glucose profiles are closer to steady state, I seek to learn the magnitude of the insulin spike on the timeline chart, upon lingual stimulation with a sweet taste.

Unfortunately, one conclusion in the Healthline article above, regarding insulin response after consumption of sucralose, may be incorrect. The article states: “However, results are mixed and other human studies have shown no effect (10).” The article referenced to support the claim that the research is mixed, used intragastric infusion. With intragastric infusion, a catheter is used to deliver the sucralose, thus bypassing the taste buds. Although, it is true that there are “taste buds” throughout the body, not just on the tongue 1

Insulin level rises when taste buds on the tongue sense anything sweet, regardless of the calorie content.
Relationship Between Insulin and Taste, 2007
Cephalic phase insulin release in healthy humans after taste stimulation?, 2008

However, this may not be the case, if the sweetness is in liquid form.
Sweet taste: effect on cephalic phase insulin release in men, 1995

In the case of adding fiber in pill form, with the consumption of a high glycemic food, the blood sugar should not rise as quickly as the body expects based on lingual signaling. So in this case, the body is over-prepared for the incoming meal.

Israel Ramirez on Quora suggested that while the answer is not known, it appears the insulin response to a sweet taste on the tongue is small.

The study Relationship Between Insulin and Taste, 2007 shows that there is a significant transient response: “3 min after the sucrose stimulation, there was a 3 to 4 times increase in plasma insulin concentration compared to levels prior to stimulation. … The rise of the plasma insulin concentration was transient, and declined within 7 min.”

I am still seeking clarification on the matter.

Stevia appears to not have the insulin response, and even reduces it:
https://examine.com/supplements/stevia