What evidence is that? The average lifespan is on the increase, not the decrease.
Or are you using some other metric to measure what you call "healthier"?
Or are you using some other metric to measure what you call "healthier"?
http://en.wikipedia.org/wiki/Life_expectancy
The first subsection is "variation over time". The drop between the paleolithic and neolithic coincides with the development of agriculture.
This is a pretty contentious issue. The idea that humanity's single most (evolutionarily) successful technology caused a massive decline in individual quality of life is pretty disturbing, and some of the evidence is contradictory. It seems like a debate best left to experts, but I thought it was worth mentioning.
I still agree with the original post -- we're very lucky to be alive now.
Looks like the article you linked to covers the same material.
http://news.ycombinator.com/item?id=533743
"We know roughly when and where farming began, because of the archæological evidence: domestication is a shock to the physiology of man and beast. The skeletons of people change, they temporarily grow smaller and less healthy, as the human body adapts to a protein-poorer diet and a more arduous lifestyle. Likewise, newly domesticated animals get scrawnier at first."
I'm sure some google wizardry could find a real source.
When we look at how the average lifespan is increasing, we're only looking at the lifespan since the start of civilization as we know it - allowed by agriculture. It's possible that our quality of life is only now catching up to what our hunter-gathered ancestors had.