His secret? Not overeating.
He tells The Sunday Times about a recent study which found feeding monkeys a low-calorie diet led to a longer lifespan.
“Maybe, I am like a monkey,” he says. “I am not completely healthy. I had heart problems, I had some pneumonia at one time and I have periods when I get bad coughs when the lungs get infected.”
The former premier points out: “I don’t smoke, I don’t drink, I don’t overeat. I eat just enough food to keep me going.
“There is a tendency for people over a certain age to become obese. They have a big stomach and to satisfy themselves, they drink and they overeat, which places a burden on their heart.
“I have been about 62-64 (kg) for years. I can wear my clothing made 30 years ago.”
Although he left active politics some 13 years ago, he still goes to the office every day.
“I happen to be healthy, I can do this work.
“For me, to say I want to go to sleep and retire and prepare for my afterlife, I think that is very selfish,” Dr Mahathir added.