However, it was not until late in his record-breaking career that the South African speedster stumbled onto a shocking truth, when he agreed to have his DNA tested.
"It was something I wasn't expecting and I was pretty flabbergasted about it. My wife has been complaining about wind since we've been married, and now I probably know the main reason!"
"Now I sort of understand why I might need to go to the toilet a bit more or why I'm a little bit more gassier than a normal person when I drink milk," he says.
"It hasn't meant I've stopped dairy, but I've changed the way I consume it."
Power or endurance?
Lactose intolerance is just one of the things Habana has discovered since starting a partnership with DNAFit
, a company that uses algorithms to determine people's genetic dispositions in regard to fitness and diet.
Habana, the Springboks' all-time leading try scorer, was also surprised to find he has greater potential for increasing the endurance side of his training than past experience indicated.
"From a mental point of view, I absolutely hate running long distances and maybe found my body got a lot more tired quicker doing them," says the winger, who has publicly released his DNA results.
"I was like, anything more than 100 meters is not my game training program. Maybe I could've responded better in terms of mentally pushing myself a bit harder. My body would've benefited a little bit more from that."
Along with power/endurance response -- which indicates what type of training intensity suits you best -- the DNAFit fitness test also provides guidelines for V02 max aerobic potential, post-exercise recovery, recovery nutrition and injury risk.
Habana teamed up with the company last year, and aims to build a DNA database of 1,000 professional rugby players by 2019.
However, he believes the test results can be just as beneficial for non-athletes as those at the elite level.
"It was very exciting to be part of a pioneering process where we're collecting as much data as possible, to be able to lay bases, to be able to find out more about the science," Habana says.
"Hopefully it'll have a big impact in making a difference in the sport, whether it be 1% for those at the elite level or 50-60% for those who are starting out in their careers and wanting to get to know their bodies better.
"What we'd like is for people to not only compare themselves to the likes of myself and hopefully a lot of other leading players in world rugby, but also to the normal person in the streets."
So how does it work?
While other DNA testing services such as 23 And Me
provide general health and genealogy traits, DNAFit focuses on diet and sports performance.
Like the other tests, it requires a simple saliva swab, which you send back to the lab. Then you receive a detailed report breaking down the results and making recommendations.
Kits cost from £99-£249 ($120-$310).
DNAFit says its Peak Performance Algorithm is based on "validated genetic variant scoring methods."
"There are genome-wide association studies," the company's special projects manager Sebastian Corpe told CNN.
"They look at elite performers in particular sports -- for example elite power athletes, elite sprinters -- and they look for gene variations that appear in them more than the average population.
"Everything about who we are is the result of an interaction between how we were born and the things that we do. Genetics just shines a light on the static part of that equation, your DNA, so you can tailor your nutrition and training strategies to what will work for you."
Which sports is it best suited to?
Corpe says DNAFit has a rugby training plan specific to players' positions on the field -- front-five forwards, back-row forwards, inside backs and outside backs.
However, the company started out testing athletes such as sprinter Craig Pickering, and employs his fellow British Olympian Tom Lancashire among its consultants.
It has also worked with English Premier League clubs and football academies. Corpe says one peer-review study with youth players
found that training according to your genetics led to almost three times the level of improvement compared to unguided training.
"We want to roll out those sorts of improvements into as many sports as possible to drive research not just in sports science but also in exercise genomics," he says.
What next for rugby legend Habana?
It's almost a decade since Habana won the World Cup with South Africa. Since then he has equaled the tournament's all-time leading try record
, having matched Jonah Lomu's mark of 15 at the 2015 tournament.
Now aged 33, he admits he is reaching the twilight of his career -- though he has prolonged it for at least another season after signing a contract extension with French club Toulon, where he has played since 2013.
He hopes the knowledge he has gained from DNA testing will help him manage his body, in an era where players are getting bigger, faster and stronger.
"Now I might be a little bit smarter in terms of how I train, in terms of my recovery process," Habana says. "I'm not going to change my whole training regime. Adding those elements that could help me train better and smarter could definitely help me over the next year or so of rugby that I have left.
"Getting that knowledge is so more useful now in terms of how I manage my career going forward and making sure that I train smarter to be able to stay at that highest level for as long as possible."
Habana, who is friends with DNAFit's founder, South African entrepreneur Avi Lasarow, says he hopes the company's approach can help take rugby to another level.
"Rugby has given me a huge amount over my career. In a small way, this is me helping to give something back, making a difference and pioneering a way where the next generation can be better, and the next generation after them can keep continually improving," he says.
"Playing a 1-2% part in making the sport grow to levels that it's never seen, I'd really love to do that. It's exciting, it's truly unique and I can't wait for it to start happening."
What else can you learn from your DNA?
CNN's World Rugby show co-host Christina Macfarlane had her DNA tested, and compared her results with Habana's.
Both have the genetic ability to quickly recover between training sessions, meaning they can potentially do hard workouts within 24 hours of the previous one.
They have a low/normal risk of soft-tissue injury -- based on genetic markers for resilience of ligaments, tendons and joints.
However, Macfarlane had a greater response to power training -- a 60/40 split -- meaning she gets more benefit from heavier weights and high intensity levels than volume-based endurance exercise, though both should be included in any program.
On the diet side, Macfarlane has a medium-high sensitivity to carbohydrates, meaning she is more efficient at absorbing calories from such food sources. If weight management was a problem, this would be a key area to address. Her fat sensitivity is low, so this may be a better source of calories.
Her antioxidant and omega-3 requirements are normal, but she needs to increase her vitamin D and calcium intake for bone health.
She is a fast metabolizer of alcohol, meaning it leaves the blood quicker, and can get an increased performance boost from a small caffeine intake prior to training -- but has a gene which means elevated consumption can deplete bone mineral density.