Love on a Diet is a 2001 Hong Kong romantic comedy film produced and directed by Johnnie To and Wai Ka-fai, starring Andy Lau and Sammi Cheng.

Wai Ka-fai is a Hong Kong filmmaker. Best known for his frequent collaborations with Johnnie To, he co-formed Milkyway Image in 1996, which is now one of the most successful independent film studios in Hong Kong.