While the focus of Korean entertainment articles centered on weight loss and fitness is often centered on female stars, their male co-stars often endure rigorous routines to better suit their characters.

A recent article published by Yonhap News examined So Ji Sub and other notable actors who go to great lengths to maintain muscular bodies for their acting roles.

In the report, Yonhap News outlined the constraints faced by actors, who often have to drop significant amounts of weight, while building muscle mass, if they are appearing in a role that requires shirtless shots.

So Ji Sub currently portrays Kim Young Ho, a renown Hollywood personal trainer, who whips Shin Min Ah into shape in the KBS2 romantic comedy, "Oh My Venus."

The 38-year-old actor, whose last major television role was in the hit SBS series, "Master's Sun," eliminated rice and salt, in order to portray the fitness guru.

"I'll show a tighter and more muscular body," said So, during a statement obtained two months prior to the premiere of 'Oh My Venus.'

According to his agency, 51K, the actor lost 15 pounds (7kg), over a two month period, to prepare for the role. During his diet, he eliminated rice, sweet potatoes, and salt. He increased his fitness regimen to include three to four hours of training per day with an emphasis on working out his muscles.

"When carbohydrates are cut, the size of the muscle [muscle mass] increases," said the spokesperson for 51K.

The "Oh My Venus" star traded out rice cakes and other treats for seemingly unappealing foods like onions soaked in water, even as the program started filming.

As a result, he has a jaw-dropping body, with well-defined upper body muscles, that turned heads while he was shooting his tub scene.