I'm actually having trouble finding the original source from WHO (as in site:who.int or just keywords on google) or on this forum stating "the WHO considers anything under 1500 calories per day as starvation".
The reference to this claim is kind of omnipresent on 30bad and health and diet articles on the blogosphere and such.
All I find from who.int is an old pdf scan of a document from the 70s stating is should be safe to increase calories per day by 50% if established that an emaciated patient was eating 1000 - 1500 calories per day prior to being admitted to a hospital...
I found this "An infant’s caloric needs (1000 to 1500 calories
per day) could usually be supplied with little effort by household food, supplemented by
mother’s breast milk." which is interesting for measure if you want to argue for an adult needing more than 1500 kcals per day to help someone out but not quite the same.
Someone must have the source? "THE source?" or any new rewording referencable to WHO?