Member-only story
Weight Loss And Longevity
Are we really on the cusp of effort-free rapid weight loss and longer lives?
Depending on your definition of the word human, our species goes back several million years. If you prefer a more restrictive view on the matter and decide only to accept homo sapiens rather than all the other branches of homo that have come and gone over the ages, then our species has been around for approximately 300,000 years. For nearly all of that time we died young: few of our ancestors lived beyond the age of thirty. Death came in a variety of forms: inter-group warfare, disease, accidents, and predators were the most notable causes but death during childbirth, starvation, and exposure also carried off a significant proportion of our hapless forebears.
After the glaciers retreated at the end of the last ice-age around 13,000 years ago, our prospects changed radically. Due to genetic mutations in various forms of grass that accompanied the warming and moistening of the global climate, in a few particularly benevolent places humans slowly (and probably mostly accidentally) developed the first rudiments of agriculture. As the centuries passed and gradual improvements accumulated, calories became less uncertain — albeit also less varied and less nutritious. Our distant hunter-gatherer ancestors ate berries, roots, seeds, and flesh as well as anything else they could find. Consequently, although starvation was always just a day or two away, they obtained on average a somewhat adequate range of nutrients. With an increased reliance on agriculture the diet of our ancestors became centered around carbohydrates, leading to an overall stunting. Based on the evidence of human remains, it appears that after agriculture took hold, humans became on average 3.25cm shorter than their hunter-gatherer forebears. Life expectancy also fell. One study indicates that whereas hunter-gatherers in southern Europe had an average life expectancy of twenty-six years, this fell precipitously to only nineteen years as agriculture took hold. Poor nutrition weakens the body’s immune system, making us more vulnerable to a wide range of stressors.
As we all know, however, our ancestors didn’t abandon agriculture. Instead, over the course of many thousands of years the slow accumulation of hard-won knowledge permitted a gradual…
