The reason is that older people right now were born before the obesity epidemic. They were thin in their youth and don't have as many built up years of destruction upon their body. But now we have fats that hve been fat since childhood, whose bodies are destroyed by the time they're 20, they won't last beyond 50. In a couple years when the youngest who were born before 1980 start getting into their 70s/80s we're gonna start seeing those of the younger generations dropping about the same time. The decreasing life expectancy is already happening, but soon it's gonna plummet.