Fudge: is it devoured by old social workers to give weight conditions? (9)

'weight conditions?' is the definition.
(obesity is a weight condition)

'fudge is it devoured by old social workers' is the wordplay.
'fudge' indicates anagramming the letters.
'devoured by' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'social workers' becomes 'bees' (bees are social insects).
'is'+'it'='isit'
'isit' with letters rearranged gives 'siti'.
'o'+'bees'='obees'
'siti' inserted into 'obees' is 'OBESITIES'.

'to give' acts as a link.