Correlation is not causation. Plenty of people theorize there is large selective advantage here, sure. They may even be correct! Others disagree with them on it

Correlation is not causation. Plenty of people theorize there is large selective advantage here, sure. They may even be correct! Others disagree with them on it being a large advantage. But even if there is it doesn't mean that there is any reason whatsoever that increased GLP-1 production would be enough of an advantage to have had significant impact on evolution. We're going from A is true, B is likely true, C might maybe be true, all the way to Z is definitely true.