5 years life expectancy difference is a lot. As a man, it is frustrating and I want to make sure I get the most out of my life (which I enjoy)
It seems evident that the taller you are, the less life expectancy you have from the simple fact that the heart has to work harder.
Hence, since men are usually taller than women, it might also be expected for men to die younger.
I am making the following scenario up, but what if a difference in men and women's bodies causes men to process cholesterol differently, and increases the probability of atherosclerosis and/or arteriosclerosis. Perhaps it happens simply because men eat more than women, and this compounds over decades of life, eventually resulting in the difference in average age at death.
We also observe that larger animals tend to live longer than smaller animals, but intra-species it tends to be the opposite (e.g. small dogs tend to live slightly longer than large dogs). It also makes some sense biologically speaking, as we now know that most genetic mutations and errors happen during cellular reproduction when DNA is copied, and cellular reproduction rates correlate with nutrient uptake, alongside mutations with age.
Of course too much caloric restriction can be detrimental, but seems to me this could explain much of the difference in life expectancy between men and women. That and perhaps the genetic advantages from having two X chromosomes.