Regularly train chef to provide food (4)
I believe the answer is:
rice
'food' is the definition.
(rice is a kind of food)
'regularly train chef' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'train'+'chef'='trainchef'
The alternating letters of 'trainchef' are 'RICE'.
'to provide' acts as a link.
(Other definitions for rice that I've seen before include "Edible grains of grass" , "Basmati, for example" , "Food crop" , "Cereal grass" , "... his librettist - cereal" .)