I don't think we can narrow the dates down quite as much as you suggest, as there may have been a delayed reaction to whatever changed. I can think of several p

I don't think we can narrow the dates down quite as much as you suggest, as there may have been a delayed reaction to whatever changed. I can think of several possibilities: increased use of plastics in essentially everything, increased use of seed oils because saturated fat was demonized, and increased carbohydrate consumption because all fats were demonized. Increased consumption of ultraprocessed foods might be a factor too.