Why is U.S. Life Expectancy Lowest Among Wealthy Nations? Could It Be Food?

Following up on my previous post on food cultures around the world, I was struck by these charts put together by Aaron Caroll at the Incidental Economist that show the life expectancy for 65 year olds in some of the wealthiest nations in the world;

Lifeexpectancy - men
Lifeexectancywomen
Of course, the startling aspect is that we come out last. Our 65 year old women, on average, live around 4 less years than Japanese women. It would be easy to blame healthcare but we have high quality universal healthcare in the US for people over 65 so it seems other factors are at play. It's pure speculation, but could it be the cumulative effect of the American diet? Could this chart comparing worldwide consumption of processed foods be relevant to these life expectancy charts? And to go even further out on a speculative limb, could reinvigorating vital food cultures (American equivalents of bathtubs full of kimchi cabbage) be a key to improving health in the U.S.?