Rebel Wilson has shed off a whopping 18 kilograms since she started her fitness journey earlier this year. Her trainer, Jono Castano, revealed what it is like to embark on a body transformation and the secret to success behind it.

In an interview with Yahoo! Lifestyle, the Australia-based fitness guru said fitness is a journey and not a race. The biggest keys to attain the desired weight are to set "realistic goals and timelines."

Castano continued that people should never opt for the easiest option when undergoing any types of transformation. Two months will never be enough to change someone's body.

The transformation process is never-ending. It will always continue, so they should never give themselves 10 or 12 weeks. Once they reach their goals, it is still not a reason to stop.

Castano advised it should become a lifestyle that they need to continue to help them become the best versions of themselves. Hence, he called Wilson's one-year wellness goal an excellent place to start.

Her fitness journey can be considered a lifestyle change. She is not mostly focusing on weight loss. Castano added nutrition is as important as exercise in the fitness journey.

One should drink three to four liters of water a day and eat to be satisfied and not full. They should also stay active, whether it is taking a walk or intense training, which also plays a major role in this journey.

According to Daily Mail, Wilson has displayed a significant weight loss since she started her "year of health" in January. She often flaunts her body transformation on Instagram.

She, recently, showed her impressive slimmed-down frame while wearing a little black dress by Alexander McQueen.

Wilson announced at the beginning of the year that she was embarking on a healthy journey. Since then, she has been strictly following a strict diet and exercise plan.

According to People, she began her lifestyle transformation when she visited a medical and wellness center in Australia, called VivaMayr, last year. She had been showing impressive results after following the Mayr Method diet plan, which mostly focused on "eating slowly and mindfully" to help digestion.

In an Instagram post, she called 2020 "The Year of Health," revealing she donned athleisure and went for a walk to begin her journey. She, also, started to hydrate herself and avoided sugar and junk food. In May, she revealed her ultimate weight goal was to be down to 75 kilograms.