Last June, Mr Chan Eng Suan, 59, switched to a plant-based diet with as little processed or refined foods as possible.
And he saw an improvement in his diabetic condition, despite having had the disease for over 20 years.
He gave up all dairy products such as milk and cheese, and, within a month, saw a big drop in his blood sugar level, so much so that he felt he could reduce his medication by half.
In another month, he did without his diabetes medication completely, despite his doctors advising against it.
Doctors say using the diet to control diabetes may not be suitable for those who have had diabetes for many years as the insulin reserves of these patients would have diminished over the years.
But Mr Chan went ahead anyway.
"I think giving up dairy products played a very important role in helping me to get better. As soon as I stopped drinking milk and eating cheese, all the problems went away,"said Mr Chan, who discovered he was diabetic in 1993, and measures his blood sugar levels at home every day.
He said he also ate more complex carbohydrates, such as brown rice, millet and buckwheat, which helped.
The polytechnic lecturer's wife, Madam Janice Ong, 52, was the one who did research on the benefits of a plant-based diet, and convinced him to try it. She also cooks dinner for him every day.
Their elder son was the one who started the ball rolling.
"He read articles and also watched a show on how people became vegan and cured their chronic diseases. And he told me he wanted to go vegan," said Madam Ong. "Then I also did some research on my own."
She is now on the vegan diet that her son is on. Mr Chan now sees his doctor every three to four months for blood tests.
He said he feels better now, with a healthy diet to control his condition.