It's important to remember that the natural GLP 1 you produce is a very very different molecule than GLP 1 agonists. The body uses natural GLP 1 in minutes. These drugs attach a very complex molecule to the GLP 1 site, allowing it to stay active there for hours.

So while your body produces it in a few places, the product gets used up almost immediately.

Keeping that in mind then, what processes do produce the (short lived) GLP 1?

It is produced naturally by the intestine and brain stem when food is present. It happens in response to fats, proteins, and carbs.

Eating high satiety foods

https://www.hsalist.org/tools/satiety-index/

That link is great, but putting jelly beans above peanuts makes zero sense to me, anecdotally. I can’t argue with the numbers/science but peanuts are something I reach for often when I’m looking to feel full, they are really great for that.