There's the possibility of using your microbiome to emit GLP-1. The key strain for this appears to be akkermansia.

Peter Attia recently had an interview with biochemist / molecular biologist Colleen Cutcliffe on what's currently understood about the microbiome, particularly the intestinal one - and that was one of the upshots. IMO worth a listen if you have a way to listen to podcasts. Subscribing gets you a few more interviews than the general public and access to really good show notes. I do this, but you don’t have to.

One of the interesting bits was that increasing akkermansia also was associated with better glucose control. But go listen to it yourself.

[edit] looks like I was unclear: that podcast is *free* [/edit]