Aged 40 but barely slowing down, Gebrselassie says his enduring presence in international athletics has nothing to do with fancy foods or the latest gizmos.
The key ingredient, he said, is in the mind.
"You have to have three things: discipline, commitment and hard work," said Gebrselassie, a double Olympic gold medallist in the 10,000 metres, four-time World Champion over the same distance and two-time world record-breaker in the marathon.
It is this discipline which drives Gebrselassie to train twice a day and clock a daily average of 35 kilometres (22 miles). Preparing for a race provides a goal to commit to, and he said some of his best training comes ahead of a big event.
He admits that the workload is not getting any easier, with middle-aged aches and pains ever-present. So fighting through physical pain and mental laziness is important too, he said.
"One of the secrets, thank you for reminding me, is to accept the pain. Without pain, no gain," he told AFP.
Despite his relative wealth -- built up from his illustrious running career plus his expanding business empire -- he insisted he still eats "what the people eat" and shuns Western, processed foods.
The "Haile diet" is no fad, being made up of Ethiopia's staple injera -- an iron-rich, fermented pancake -- plus lots of lean, raw meat. His home country also provides him with an ideal location to train, he said, with its temperate weather and high altitude.
"The best place for training of course is Ethiopia, for me I don't see any place like Ethiopia, I'm serious," said Gebrselassie, who still starts most mornings by running in the lush green hills surrounding the capital, Addis Ababa.
'Age is just a number'
Gebrselassie is widely considered one of the world's greatest-ever athletes, and back home his legendary status is rivalled only by Abebe Bikila, the "barefoot runner" who won gold in the marathon at the 1960 Rome Olympics.
In his storied career that has spanned over two decades, Gebrselassie has won multiple Olympic and World Championship medals, setting 27 world records along the way.
Like scores of other Ethiopian champions, he started running as a child when he travelled barefoot from his humble rural home to school, a 20-kilometre round-trip. He said the 10,000-metre race is still his favourite, because it reminds him of his daily journeys to school.
Despite nearing retirement age, he continues to run competitively, racing alongside much younger competitors, including last month when he finished a close third behind his compatriot Kenenisa Bekele and Britain's Mo Farah in the Great North Run, a half marathon in northern England.
Continuing to break masters records in the over-40's category, Gebrselassie is showing no signs of wanting to hang up his shoes: he will run the "seven hills" 15-kilometre race in the Netherlands in November followed by a half marathon in the coming months.
"It's very hard to break the world record (now), but we'll see, I don't want to be very far from the others," he said.
"I want to show the youngsters what running means, I want to tell them 'age is just a number'. If you think you're old, if you tell to yourself you're old, if you're old mentally, then you're old automatically physically," he said, flashing his characteristic wide grin.
As for the years ahead, Gebrselassie said he is eyeing running for parliament in 2015 as an independent candidate as a chance for him "to give back" to his country.
Although Ethiopia is developing rapidly, he said growth is not happening fast enough and that he would like to see progress at "Usain Bolt" speed.
"I'd like to see my country like Europe and America. We're doing good, but it's just the pace, the pace is not good enough," he said.
But regardless of what the future holds, he said he won't be sitting back and gaining a middle-aged spread.
"I cannot stop running, running is just a part of my life," he said.