Humans are vulnerable to heart attacks and strokes. Our modern diet leads to atherosclerosis, this already starts at a young age but it doesn't cause symptoms until an important artery is almost completely blocked or if a piece of plaque ruptures and causes a sudden shutdown of the blood supply to parts of the heart or brain.
However, if people eat like many indigenous people such as the Tsimané do, then they get far less atherosclerosis:
“Most of the Tsimané are able to live their entire life without developing any coronary atherosclerosis. This has never been seen in any prior research. While difficult to achieve in the industrialized world, we can adopt some aspects of their lifestyle to potentially forestall a condition we thought would eventually effect almost all of us.”
Similar results had been found previously, but this then relates to coronary heart disease not merely the presence of atherosclerosis, see e.g. here:
Williams and Jack Davies had shown clinically and pathologically that coronary heart disease was almost non-existent among the African population in Uganda, although Hugh Trowell had reported a single case of coronary heart disease in an African judge. In the Asian community of Uganda, on the other hand, coronary heart disease was extremely common, accounting for almost half of the male deaths in Kampala in 1956–1958.
The question is then how we could have evolved to be almost free of atherosclerosis when sticking to such a lifestyle, given that atherosclerosis doesn't cause symptoms until it has progressed quite a lot, which is typically late in life and that then in the developed world. For indigenous people like the Tsimané it's even less relevant, because they have a much lower life expectancy due to infections.
Nevertheless it does look like our ancestors did evolve such that they didn't get atherosclerosis.