'Once the clothing starts to feel tight, people become more ready to come into the gym,' said Kent Richards, Hong Kong managing director for the health chain Fitness First.

He said daily visits to its seven branches had increased as much as 25 per cent this month.

More importantly, he adds, about half of this rise in gym traffic comes from a mix of more frequent visits by existing members and returning members who had turned in their gym cards.

Bargain-end rival Physical reported a similar rise in gym traffic, while California Fitness - another popular chain - said visits by members had risen by 20 per cent last month.

Peter Prickett, chief operating officer of newcomer Pure Fitness, said: 'No one actually enjoys gaining weight. But many individuals allow their physical condition to deteriorate over the winter months.'

Come summer, and the prospect of exposing oneself in a swimming costume gave people extra motivation, said Andrew Ward, regional operations manager of California Fitness.

Fiona Chan, an assistant lecturer at the University of Hong Kong's department of psychology, blames the annual rush to the gym on the idealised body images projected by advertising.

'Our society so very focused on how a person looks,' said Ms Chan. 'If people feel that their bodies are far from what the ideal concept should be then they will be motivated to do something.'

Still, the main question remains whether it is too late to start taking off weight so easily put on just a couple of months ago.

According to Ms Chan, that depends on how realistic people set their goals before they head for a work-out.

'Everybody starts from a set point and they try to work towards an ideal body. If this ideal is far from where they are at, then even though they are making progress, it's hard for them to feel motivated and keep going.

'Personally, I think nowadays people in Hong Kong are trying to set unrealistic goals.'