Funny that. The edition of Dr Spock which I used said that the idea came from incompletely or inadequately controlled clinical trials on human babies.
Gastro-enteritis etc used to be major killers, evn in the developed world. Trials of methods which involved scrupulous sterilisation somehow also introduced a rigid time table. The death rate was cut dramatically
I suppose that makes sense in a way - if feeding times are erratic & unpredictable it gets harder to ensure sterilisation
It took time to establish that a rigid feeding timetable in itself had no independent effect on the risk of disease
There are eternal lessons here. Make sure that you have thought about all the confounding variables.
And why do we have to keep on re-learning the message about cleanliness?
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