old work, but cant find anything newer or in english
Probl Endokrinol (Mosk). 1984 Jul-Aug;30(4):67-9. Related Articles, Links
[Aspartame--the sweet-tasting dipeptide--does not affect the pancreatic insulin-secreting function]
[Article in Russian]
Sadovnikova NV, Fedotov VP, Aleshina LV, Shvachkin IuP, Girin SK.
The action of a synthetic dipeptide aspartam (150 to 180 times as sweet as glucose) on pancreatic insulin-secretory function of rats was studied in vivo and in vitro. The drug was given orally while drinking (300 mg/kg body weight) or was added to the incubation medium of cultivated pancreatic cells (20 mM). It was shown that insulin content in the rat blood serum remained unchanged 10 and 35 minutes after aspartam administration. The drug did not exert any stimulating effect upon insulin secretion following the addition to the pancreatic cell culture medium. It is concluded that aspartam exhibits no direct or mediated action on pancreatic insulin-secretory function.
There is other work with differetn sweetners showing an effect, but it was injected, rather than oral dosing which is a world apart from reality. Insulin secretion is a tad more complex than "Because they are sweet, the body still releases insulin"
Leucine is not sweet, but it stimulates insulin quite nicely