Filipino Eugene Ranada was detained at immigration when he tried to enter South Korea for a business trip last month.

His passport photo looked nothing like the person he is today after the 45-year-old software developer lost 40kg in 11/2 years.

Said Ranada, who was questioned at Seoul's Incheon airport for 15 minutes: "I had to show them my IC too and the officer kept tapping my card on the table to check if it was real."

The Singapore permanent resident, who once tipped the scales at 120kg, is training for the 42km Sportive Ride at the May 5-6 OCBC Cycle.

Growing up, the 1.73m Ranada was never obese, but the weight started to pile on when he entered the workforce, due to his sedentary lifestyle. Weighing 115kg in 2012, he decided to pick up cycling to lose weight.

"I chose cycling because I've always liked it. I couldn't run, I was heavy, my knees totally didn't allow me to run. I didn't know how to swim either," said Ranada.

He started riding for leisure and even took part in the OCBC Cycle later that year. But he barely made it up the Benjamin Sheares bridge and had to get off his bike and push it up the steep slope.

Calling the incident a "shameful moment", he vowed to come back stronger in 2013.

But a cycling accident at Bishan Park a day before the 2013 OCBC Cycle saw him suffer two broken ribs and a shattered collarbone.

He was out for three months and completely avoided physical activity as he developed a phobia of cycling. "I stopped cycling, sold my two bicycles and completely gave up," he said.

His weight started to increase again and he was diagnosed with a heart condition which caused his heart rate to double without warning.

Said Ranada, who weighed 120kg at his heaviest: "I was just reading and writing some notes one day and suddenly my heart rate just doubled.

"I panicked and measured my blood pressure and it was 190 over 150, which was really high."

A healthy blood pressure reading is typically less than 120 over 80.

His health and quality of life declined until a stark reality hit him: His wife and eight-year-old son needed him.

Said Ranada:"I don't want to leave them suddenly because of my bad health."

He started walking in late 2014 and soon progressed to light running and cycling on the stationary bike at the gym.

In 2015, he decided to overcome his fear of cycling as he had missed riding outdoors. He bought a foldable bike and started with 10-minute sessions at the park.

He gradually increased his distance and now cycles three times a week - 36km on Monday and Wednesday and 80km on Saturday - with some friends from Joyriders, a local cycling group with more than 100 active members. He also learnt how to swim in 2016.

With an active lifestyle and a healthier diet, Ranada lost 40kg between the end of 2014 and early 2016.

"After I started cycling again, I noticed changes to my weight. Every month I lost about 4kg," he said.

He weighs a healthy 75kg now and no longer suffers from heart problems.

This time round, he aims to conquer the Benjamin Sheares bridge at the OCBC Cycle.

"The first time (2012) I had to get off and push my bike, in 2013 I couldn't take part because of the accident, so this year I really want to do it," said Ranada.

On his transformation, he said: "It starts with motivation. If you don't have it, you won't even begin to think about losing weight."

•Today is the last day to register for The Sportive Ride. For more information, visit www.ocbccycle.com