In Bittersweet, an offering at the ongoing Japanese Film Festival, the vegetable-hating Maki is tempted by the delicious-looking vegetarian dishes whipped up by her housemate Nagisa. And why not? The food looks invitingly fresh and colourful and the audience can almost smell the aromas wafting from the screen.

Director Shogo Kusano says that what makes food shine best on screen is when they are oily and glossy. "The small reflections on the water and oil are important," he says in an e-mail interview with The Straits Times.

However, vegetarian dishes tend to contain less fat. The solution was to pay a lot of attention to the lighting and camera angles.

Kusano, 32, adds: "Since the reaction of the person who eats is important to make the food 'look tasty', I also focus on the direction for how to eat."

Bittersweet, rated M18, will be screened at the National Museum tonight at 7.30pm and tomorrow at 4.30pm as part of the Japanese Film Festival, which runs till tomorrow.

The film is adapted from a manga of the same name, which is about a vegetable-hating woman who works at an advertising agency and her gay vegetarian teacher housemate.

Kusano, who had directed the teen sci-fi drama Karappo (Empty, 2012), points to a key challenge of adapting a manga work.

"If we find some actors who just look like the manga characters, it would be just a cosplay."

Instead, he wanted to focus on the characters themselves and yet still have the film win over fans of the manga.

He says of actress Haruna Kawaguchi: "I think she played Maki perfectly and cutely, a character who has maturity and a childish side."

The bigger directing challenge was Nagisa and he says that actor Kento Hayashi helped bring the role to life. Even though Hayashi does not cook in real life, he learnt to handle knives and was so dedicated that all the close-up shots of the hands during cooking were actually his.

While Maki is won over by vegetables in the film, the director says that he has no intentions of proselytising with his work.

"Maki doesn't become vegetarian, but she just likes the dishes cooked by someone she likes. And she realises that dishes cooked with affection and a careful diet are much better than her previous diet of fast food and supplements."

Kusano himself is not vegetarian, though he does try to eat healthily.

"I didn't like vegetables when I was a kid. However, I realised how important vegetables are for my health a few years ago and now I try to eat well-balanced meals."

Bittersweet was released in Japan on Sept 10. Its inclusion in the Japanese Film Festival marks the international premiere of the title in a country where people are passionate about food - a fact which makes Kusano happy.

"It would be wonderful if people in Singapore watch this film and wish to eat the food in the film or even cook them. I cook Hainanese chicken rice at home."