Bones and Standard of Living

[Nathan Ross]

Walter Scheidel... "mean stature in the Roman period was lower than both before (during the Iron Age) and after (in the Middle Ages)... a strong increase in body height in the late Roman and early medieval periods. An unpublished survey of 1,867 skeletons from sixty-one sites in Britain likewise documents an increase in body height after the end of Roman rule."

Scheidel's quite interesting (even if, as I've said before, bioarchaeology doesn't tend to grab me) - I cited some of his work before in this thread about plagues.

Also in that thread I quoted D.S. Potter's idea that the Roman empire was constantly at the limit of its 'carrying capacity': this overpopulation was caused in part by a decline in infant mortality. When plague increased mortality, quality of life for the survivors increased with it.

We might also consider the wastage of arable lands caused by Roman-era intensive farming, which might have led to the creation of 'agri deserti' in the west (large tracts of arable land in Belgica and northern Gaul appear to have been abandoned to wasteland and scrub forest by the late 2nd century). This in turn would have put even more pressure on a population forced to subsist on dwindling resources. Much of this agriculture was also cash-crop farming, which enriches landowners but reduces the amount and diversity of food 'trickling down' to the lower levels of population (a problem that recurred into the 19th century...)
 
But it's interesting that Scheidel says the situation changed 'in the late Roman... period' (in your quote above), or in 'the fourth century CE when this trend [of declining bodily height] was largely reversed'. Why might this be?

One suggestion might be a change of population - settlement of Germanic, Gothic or Sarmatian people in Italy, either an laeti or as migrants, perhaps? - raising the average height, or just bringing a different sort of diet: more meat and dairy, maybe?

Alternatively, the population might have been thinning out, due to disease, increasing infant mortality or increasing violence (brigandage, invasion?), and the surviving population would therefore have had access to greater resources. I think this is what Scheidel refers to as the 'Malthusian' explanation!