HONG KONG (Reuters) - Mooncake sellers in Hong Kong are offering healthier choices this festive season to attract a customer base that is growing ever more wary about its calorie intake.

A culinary staple of the Mid-Autumn Festival, mooncakes are traditionally filled with lotus or sweet bean paste, contain an egg yolk and are made with lard. These ingredients make for a high sugar and fat content.

At vegan-inspired Sesame Kitchen, chef Shina Shimizu is swopping out those ingredients in her own version of the mooncake, incorporating instead coconut milk, sesame seeds and matcha green tea powder.

"People are definitely looking for healthier options," she said. "Also some people want to enjoy mooncakes but cannot, because of dietary restrictions on pork, and more and more people have allergies."

Upscale cake shop The Cakery advertises mooncakes in sesame, gojiberries and fig flavours, and says they are free of gluten, dairy, eggs and refined sugar.

Health-conscious customers appear to be won over, although Hong Kong resident Helen Hung said she also buys a traditional mooncake and only eats a tiny portion. "I know that it is not healthy, too much sugar," added Ms Hung.

"But I have to buy because that is my traditional culture."

The Mid-Autumn Festival is a harvest festival celebrated on the full-moon day in September, when families get together to give thanks and feast.