What a DNA test can teach you about diet and fitness

DNAfit has worked with Olympians, tapping into their strengths and weaknesses to help them train and eat accordingly

DNA testing can give a surprising insight into fitness (Getty Images)

There are a couple of things I always suspected were written into my DNA. My tendency to leave the house with wet hair. The innate ability to forget my original mission the second I reach the top of the stairs and the "fat knee syndrome" that forever prohibits those trendy rippedknee skinny jeans. But what if DNA held the secrets to your health, sporting ability and even diet success? DNA testing is not a new phenomenon when it comes to health. Angelina Jolie brought the subject to the fore when she had a double mastectomy after finding out she was carrying the BRCA1 gene, a hereditary gene which massively increases the likelihood of developing breast cancer. For those with a family history, this kind of genetic test can be a lifesaver.

One personal genome company, 23 and Me, tests for 100 different genetic conditions. It was banned in the US amid doubts over accuracy, but has since launched in the UK and was reintroduced Stateside last year with FDA approval for genes related to 36 diseases, including sickle-cell anaemia and cystic fibrosis. Not only could tests be a key to exposing medical predispositions in individuals, the vast genetic database that is being built (more than a million people have signed up) could be used in future research and diagnostics.

From the specific to the broadspectrum and everything in between, it is certainly an area where we can discover a treasure trove of information about our own bodies. Since it launched in 2013, DNAfit has worked with Olympians and other athletes, tapping into their personal strengths and weaknesses and helping them to train and eat accordingly.

In a time when we are increasingly bombarded with conflicting and often bogus information on diet and exercise, this sounded promising. I was sent a relatively foolproof home-testing kit, and sent my DNA winging its way back to the test centre. All it takes is a firm cheek swab to get a good DNA sample - no bodily fluids required. Within a couple of weeks, my results were back, along with some nifty infographics and some potentially life-changing advice. I set up a meeting with Olympic runner Thomas Lancashire to talk me through my results.

Some of it I probably could have guessed, and I ticked off all the right answers instantly. My body doesn't like carbs. Or, well, it does, so much that it powers through them and lays them down as fat (check). So a low-carb diet is the order of the day for me. Happily, though, I'm OK with saturated fat. So break out the butter. Another non-surprise - I metabolise alcohol very slowly. This means I get drunk more quickly (check). Although that's good for my cholesterol - those who metabolise booze quickly don't have it in their bloodstream long enough to take effect. And I have a higher pre-disposition to coeliac disease - a one-in-35 chance rather than onein-a- couple of thousand. (Check. I was diagnosed a few years ago.) When it came to my fitness, however, I was in for a few surprises. Lancashire explained to me that, in general, I had the potential to get pretty damn fit. I have a good VO2 max score, so potentially can increase my lung capacity and regain fitness levels quite quickly. I have a tendency towards injury but a fast recovery time from exercise. So, while I need to be careful not to strain ligaments and such, I can in theory exercise every day without needing to rest up in between.

Thomas explained that I should be aiming for five to six sessions a week, mixing up power and endurance training as my suitability is split almost 50/50. That means I'm best suited to high intensity resistance training or HIIT classes and spinning. And no excuses. Lancashire says a tool like this helps to really tailor an exercise programme. "Normally, a trainer would need to know a lot of information about a client - their family history, background, lifestyle - to really see results. This allows us to make more informed decisions when devising training plans." However, he admits that it isn't perfect. "It's not a magic bullet. The environmental side varies from person to person, so we have to take that into account."

Diet-wise, apart from cutting back on the refined carbs (bye bye sugar), I discovered that I don't necessarily need a higher than normal intake of cruciferous veg, but could do with cutting down caffeine and salt. Double the normal RDA of omega-3 was advised - it's a good anti-inflammatory for my injury-prone body. And I was told to increase my intake of selenium, something that never really crossed my mind, with foods like brazil nuts, tuna and seafood. Selenium has antioxidant properties so perhaps that will balance out the bacon? The genes that DNAfit uses have to have been identified in several clinical trials as useful to human health. Every section of the test compares different genes to calculate your predisposition to gain weight, pick up injuries, or even how well your body detoxes the chemicals in charred meat. I learn that the ACTN3 gene, for instance, is the sprint gene, which helps to produce the fast-twitch muscle fibres that give shortdistance runners that explosive power. The FTO gene is the fat gene or the obesity gene. An "AA" rating suggests that you are likely to convert fat straight to fat, and a "TT" rating suggests that fat intake has little effect on body weight. I also learn that while I can tolerate a certain amount of fat, it's probably best to lay off the barbecues - my detoxability factor isn't great.

Lancashire stresses throughout the consultation that the information provided is just a baseline, and must be used wisely. A DNA test may tell you you are not prone to injury but it won't know if your twice-fractured ankle still gives you problems. I may in theory be able to exercise five to six times a week, but as I have multiple sclerosis, there will be some weeks when walking to the shops is an achievement, let alone being in the front row at a spin class.

The nature-vs-nurture debate remains to the fore: how much of our health is governed by environmental factors? Lifestyle, diet, stress, even pollution can play key roles.

There is also a somewhat sinister side to genetic testing, and the movement has its fair share of sceptics and conspiracy theorists. Our DNA is unique like our fingerprints - the personal road map to our lives and bodies. I merrily swabbed inside my cheek and posted off my unique information without a second thought and barely a glance at the terms and conditions. Critics fear that in the future our DNA could be used by marketing agencies for targeted advertising, and even insurance companies to hike premiums or even disqualify people with underlying potential conditions. For now, though, I'm happy to use my genetic information to reintroduce milk to my diet, alter my training regime and maybe even consider cutting back on carbs. Only time will tell whether my new-found genetic insight will get me back into the skinny jeans...