It could be argued that people are just reclaiming old meanings. At least for 'meat' and 'milk'.
1,000 years ago, 'meat' just meant food. It wasn't until the late 16th century that it started to become mainly used to denote animal flesh. Shakespeare's time.
Its use to refer to the 'flesh' of fruit nuts or eggs etc goes back to the 15th century.
As for 'milk', it was used in 1398 to describe the "mylke of the fygge tree".
Nothing new here.
I'll give you mayo (the abbreviation appeared in the 1930s whereas the first written example of "mayonnaise' is from the Victorian novelist Thackeray in 1841,)
