Indeed, and such a mechanism was proposed as possibly ancillary, not ruled out.
Okay, but I understood your question (“Have humans not been getting taller?”) to mean that you were suggesting the evolutionary trend was actually opposite to that reported in the Framingham study. The linked-to article in the OP does indicate that the study was controlled for nutritional factors. It may thus be that in reality tallness/slenderness is in modern times being genetically more fully expressed due to improved living conditions, but that is also being selected against, rather than shortness/plumpness being selected for. The important question to ask is what factor(s) may be propelling the selection because the background genetic material was drawn from essentially the same population. As such, the variations therein would be within statistical expectation.
Sure, but it wasn’t asserted that evolution, or genetics for that matter, plays no role.
It could be argued that fashion plays a role in the selection of a sex partner. If tall, slim partners are in vogue, there would be social status associated with partnering with such a person. Such social status might overrule more hereditary preferences in partner selection. Considering that fashions change and can be quite whimsical, the distinction between natural and artificial selection becomes blurred in such a situation.
The health of the parents and the food the parents consume, before and during the pregnancy determines how healthy you are later in life. Wouldn’t the food they eat determine aswell how much weight you carry during your life time? If you were to imagine a mother not having enough food to eat, wouldn’t the child be underdeveloped. And then also a child being born premature has a effect to.
So I think there is various factors that can determine this, both internal and external.
Maybe lactose tolerance and tallness are linked - it is very difficult to find dairy products being sold in countries such as China and Thailand and indigenous people of these countries are noticeably more vertically challenged.(Apart from Bao Xishun one of the tallest men in the world) Of course many people now also include Western junk food in their diets, but on the whole it has been the same for generations. Short breeding short.
Just an observation on my travels.
And what a challenging observation, beLIEf! (+1)
Now figure this out: If lactose tolerance is driven by natural selection and tallness is linked to lactose tolerance, would that (necessarily) imply that tallness is driven by natural selection?
In that case Hermes, then yes I believe it would. Perhaps a combination of natural selection and slight mutation since lactose intolerance still exists in individuals in otherwise lactose tolerant nations. I think people are significantly more likely to choose their partners based on their height rather than their love of dairy products - but then the tall ones might only be tall because of their ability to digest moo juice… a conundrum indeed. Which came first tall people or dairy farming? ???
Most southern African indigenous ethnic groups have been nomadic cattle herders for several centuries, living off dairy in addition to beef. Their lactose tolerance is hardly in question. Yet, they are on average short and slight peoples by European/US standards with the Kenyan/Tanzanian Maasai being one exception in the tallness department. This seems to run counter to any simple link between lactose tolerance and tallness.
Of course there’s a strong genetic component in this. It applies within ethnic groups as much as between them, but the question is how increasing tallness in recent human history is best explained: evolution or improved living standards?
Does that mean all you hero members have apostrophilia??
I wasn’t implying the link was simple, just interestingly observable and of course nutritionally speaking would linked to a myriad of factors other than lactose. I think tallness is rather a result of both evolution and improved living standards, maybe the thing that needs clarification and is more difficult to determine is which factor has had the greatest influence.
One could also look at it from the opposite side and argue that in situations where food is scarce, such as among the hunter-gatherers, there is a competitive advantage to being small and able to survive on less food.
Yes that would totally make sense as not only would people be smaller because of less food, but having a smaller body mass also requires less calories to sustain. Isn’t nature clever?!
The surviving on less food idea is an interesting one and opens up some other avenues of discussion. Lewis Wolpert discusses this briefly in his recent book “How we live and why we die”. Simplistically, one might think that more food = better growth, healthier bodies, better reproductive ability, better survival, better propagation of genetic material. However, there is evidence from animal studies that eating less (a lot less!) can significantly extend the lifespans and reproductive age in a variety of animals.
In rats, the studies showed that a 50% reduction in food led to life spans that were 40% longer than the well fed rats. More relevant to this discussion is that the max reproductive age of female rats almost doubled. Sufficient vitamin and mineral intake was important but it didn’t matter whether the calories came from fat, protein or carbs.
Alarmingly, if the restricted feeding regime was stopped, the aging process then actually seems to be accelerated.
Yes there are loads of articles about the benefits of having a lower calorific intake and obviously eating less of certain foods. Longevity being the most widely claimed benefit. Even if the reduction is for a limited period of time.
So could it be that religions - most of which have periods of fasting or abstinence from certain foods have also contributed to people in certain nations living longer and healthier lives? (or at least offset some of the lives lost in holy war or the counter- health benefits of being wracked with guilt
I wonder. Is religion equivalent to fad diets? For example, the sort where you only eat cabbage and lemons for a month and hope to morph into Kate Moss.
Are you aware of instances where populations have gone into natural decline because of an abundance of food? I don’t mean soil that is too rich for certain plants.
LOL! If Pikkiwoki keeps on making unreasonable demands, he’s destined for the great divine scrap-heap, along with Yahweh, Ra, Thor and countless others. These gods need to keep in touch with their markets.
Anyway, sorry for the derailment - temporary I hope.
