Artificial sweeteners do not spike insulin levels
Claims that sweeteners cause an spike in insulin without consumption of sugar are mistaken! This study looked at blood insulin levels after consumption of glucose, fructose, aspartame and water. It found that only glucose and fructose caused rises in insulin.
Aspartame is one of the most studied substances in the world. We present the evidence for the safety of aspartame as an artificial sweetener because the alternative usually is to consume foods/drinks sweetened with refined sugars. It is very possible that long term studies may one day show harmful effects of artificial sweeteners like aspartame. Make no mistake: the evidence for the dangers of refined sugars is undeniably stronger than the evidence for the harmful effects of artificial sweeteners. Refined sugar has the strongest causative connection to making you overweight and even obese. This is largely due to caloric density and limited satiety, easily resulting in a caloric surplus and weight gain over time. Obesity is in turn linked to an array of other diseases, such as type 2 diabetes, heart diseases and certain cancers.
Rodin J. Comparative effects of fructose, aspartame, glucose, and water preloads on calorie and macronutrient intake. Am J Clin Nutr. 1990 Mar;51(3):428-35.