Conversation so far:
Did Donnie Yen work with a trainer ?
Donnie Yen later went on to study the art of Parkour, Wrestling, Muay Thai, Kickboxing and Boxing under various trainers.
What kind of exercise did Donnie Yen do to bodybuild ?
Donnie Yen had to regain his muscular physique for the role and took 6 months through a very delicate and dedicated diet routine.

Question: Was that to gain weight or lose weight ?
Self-contained rewrite: Was the diet for Legend of the Fist: The Return of Chen Zhen to gain weight or lose weight ?