During their courtship, when they were doctoral students at the University of Hawaii in Honolulu in the late 1980s, they would look for Japanese and Chinese restaurants which had vegetarian options.
Dr Jacobs adds that having different diets has helped keep things interesting in their relationship.
The oldest of three children says: "It helps that I understand the perspective of meat-eaters and it challenges me to make vegan-friendly dishes and smoothies that my wife will find tasty."
The learning adviser at James Cook University here is from the United States. He and his Malaysia- born wife, who works in a bank, moved here in 1993 when she got a job here. They have become Singapore citizens and have no children.
Dr Jacobs has been heading the 16-year-old society for more than a decade. It has 600 members and organises activities, which encourage the public to include more plants in their diet.
These days, he dines mostly in non-vegetarian restaurants with his wife and does not find it difficult to eat vegan, as a growing number of restaurants are catering to people like him.
Have you tried convincing your wife to become a vegetarian?
I do not impose my beliefs on her. She believes in the benefits of going vegetarian, but she finds it difficult to give up the flavours and comfort derived from local food.
Why did you become a vegetarian?
I was 27 when I read the book Diet For A Small Planet by Frances Moore Lappe, which talks about how meat consumption contributes to food scarcity. We have sufficient food, but are feeding them to animals. I felt that it wasn't fair and wanted to do something. I was also influenced by my cousin, who was a hippie and thought it was cool.
I watched a video, Meet Your Meat by the People for the Ethical Treatment of Animals, and saw horrific scenes in factory farms where as soon as the hens and cows produced less eggs or milk, they were slaughtered for meat.
What was it like being a vegetarian?
Being a vegetarian in Ohio was a lonely journey. I had few cooking skills and little nutrition knowledge. My diet wasn't healthy, as it consisted of grilled cheese or peanut butter sandwiches. Initially, I missed the burger treats and seafood. My family wasn't thrilled but they catered to my diet.
What's the biggest misconception people have about vegetarianism?
That one cannot be healthy. Most people are brought up to think that protein and calcium can come only from meat and milk but there are alternatives such as beans, lentils and nuts.
For nutrients lacking in a vegan diet such as vitamin B12, there are fortified foods such as cereals and supplements.
How is your cholesterol level?
My cholesterol level is not in the bad range, but it is not as low as one might think it would be. My mother had problems with her cholesterol level. Being a vegetarian lowers the risk of conditions such as diabetes and heart disease, but it does not guarantee immunity from these diseases.
What are your favourite vegetarian eateries in Singapore?
I like Genesis Vegetarian Health Food Restaurant in Boat Quay for its vegan lasagne, and vegetable and mushroom dumpling soup; New Green Pasture Cafe in Fortune Centre in Middle Road for assam laksa and herbal soup; and Eco Harmony Kitchen in Aljunied Crescent for popiah and "bak kut" teh.
What would you do if the only vegetarian food stall in the hawker centre is closed?
https://youtu.be/KqtIlaU9IHU
I would look for an Indian Muslim stall for briyani rice and dosai with dhal curry or a Malay food stall for tempeh goreng, or have Hakka thunder tea rice without the anchovies. I can look around for fruit or order fried rice without eggs and meat. I am not worried about going hungry.
What food quirks do you have?
I feel disgusted at barbecues and walk in a certain way to avoid the wet section of a market as I visualise animals getting killed.
If you could choose anyone to have a meal with, who would it be?
My late parents, who were social workers.
My mother died from cancer more than 10 years ago, when she was 75, and my father died from heart disease more than 40 years ago when he was 50.
I was a typical uncommunicative teenager and would like to share more with my father about how my life turned out.
WHAT WOULD YOUR LAST MEAL BE?
A big fruit salad filled with grapes, coconut, apple, watermelon, mango, jackfruit and durian, topped with almonds, sunflower seeds and raisins.
A version of this article appeared in the print edition of The Sunday Times on July 19, 2015, with the headline 'Going green for life Foodie Confidential'.
