It is perhaps implicit in some of the previous responses, but I just want to point out that there is both a specific and a general meaning to this expression.
The original specific meaning is literally that for someone who converted at one of the evangelical soup kitchens, which were not confined to the time of the Great Famine.
By extension, however, it was applied to **anyone** who converted, whether they had anything to do with a soup kitchen, or not, and was used for many generations after the actual original events.
