But you also take up resources, continue to decline physically, etc.

We know that there is strong selection pressure for things that occur during reproductive years. No one debates this.

How much the sort of scenarios you're discussing impact selection pressure is significantly less clear.

But it's also a moot point for this discussion - we haven't been in a world where people can get this fat so easily and in such large quantities for long enough to make significant impact to evolution even if we assumed that selection pressure works the same in said world - and again, we know it doesn't.

Grandparents are a selective advantage well after reproduction. Older members of the tribe can watch the young while fitter members engage in hunting and foraging. They can also teach the young. Most tribes around the world that still exist you see this pattern.

But for an ancient tribe grandparents means 35-50 years old people. Just as health starts to decline in modern humans.

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.

To increase chances of survival of the population you need just an extra 10y after the end of reproduction to grow last child, no more.

> Yet women have a longer lifespan despite shorter reproductive years.

After industrialized nations have reduced both maternal mortality and violent death (warfare) to small fractions of their pre-modern levels. The life tables of 1500, 500, or 5000 BC would look very different than their modern versions.