One might guess that around 1995, something happened to the US food supply. Maybe the big surge of GMOs (which didn't happen in Europe because they're banned)?
GMOs are not banned in Europe as a whole, but it looks like only Spain have a significant GMO output [1]. Coincidentally Spain has a nice life expectancy, so there doesn't seem to be an obvious correlation (one might argue that Spain might produce but not consume most of it GM crops, which I don't know).