NEWS

The case for personalised diets is gaining weight - with a new one, based on each person's unique DNA structure, now on the table. We've already had the body-shape diet, the blood-type diet and the facial-analysis diet, so perhaps the era of one-size-fits-all eating plans is finally ending. (See 'Made-to-measure diets'.) Not yet, argue sceptics who - while not suggesting the new DNA diet is harmful -think we don't yet have enough scientific knowledge to make it work. The diet, now available to South Africans, is based on a new branch of nutrition science called nutrigenomics, which researches the link between each person's genetic make-up and the particular way her or his body interacts with nutrients.

According to DNAlysis, the company developing the diet, 40% to 80% of our variance in body weight is due to tiny differences in our genetic profile that make a big difference to the way our body responds to various foods. This explains why, for instance, one person may become obese living pretty much the same way as another who doesn't. Proponents of the diet believe taking account of differences in our genes can, well, make us more comfortable in our jeans! 'Studies have shown that people on a diet matched to their gene profile lose six percent more weight than those who aren't,' says Yael Joffe, a nutrition geneticist and one of the South African pioneers of the diet. Many diets are a process of trial and error, she adds, which can be discouraging. Devising a diet to suit an individual means the chances of success are greater, she says.

TO THEIR TASTE
Jackie Wells, 34, a sports physiotherapist in Cape Town, says the diet is working for her. A Comrades Marathon runner, she had assumed that training intensely for the race would help her lose weight. 'But I actually gained 5kg!' The DMA-diet tests revealed that pushing herself hard was making her weight-loss resistant. 'Now I don't work out as much. It's taken a lot of pressure off me.' Despite exercising less strenuously, Wells has lost 4kg in the two months since she went on the DNA-based diet. Clearly, battling to lose weight is not always about laziness! Some of us need more exercise and some of us need less. For Cara Kahn, 34, a Cape Town The focus is on steadily achieving a healthy weight and then maintaining it, rather than on quick, short-term weight loss


PLACE AN ORDER
Getting a DNA diet plan is simple (although, at R1 350, it isn't cheap). You visit www.dnadiet.co.za and order a DNA test kit online. It's delivered by an overnight courier and contains a cheek swab, a questionnaire and an indemnity form. You fill in personal information about your eating habits, exercise levels and lifestyle (for example whether you drink or smoke), take a sample of your saliva from the inside of your cheek with the swab, which looks like an earbud, and send it to the address provided for testing. Once the lab results come back you will receive an e-mail confirmation with a link to where you can download a detailed report with a recommended diet and exercise plan. Clients are told upfront of the diet's limitations - no-one is pretending it's business owner, the greatest advantage of the DNA diet is knowing what her body needs and what it doesn't. In her case, the test revealed that she needed to do more cardio. And cut out bad fats. 'But generally I already eat healthily, so the diet didn't cause a dramatic upset in my life and I was able to adapt easily,' she says.

MORE COURSES TO COME
Medical researchers, dietitians and nutritionists who have reservations about the DNA diet acknowledge that it is basically sound but believe much more work needs to be done. They feel it is not yet comprehensive, as it analyses only eight of the 600 or so genes that affect weight - which is a bit like trying to imagine an entire landscape by looking through a keyhole. Effective use of this diet is still at least 10 years away, they believe, as researchers are still discovering new genes and their connection to weight and nutrition. 'Nutrigenomics is a new frontier of research and needs to be explored further,' says Anne Till, dietitian and director of Anne Till & Associates. 'Using DNA for weight control now could be premature, but they are offering what is available at present.'

The people at DNAlysis agree. Joffe explains: 'Nutrigenomics is a difficult science because it is continually evolving. But it seems wasteful to sit on sound information that's been validated by science. When is a good time to share it? When we discover 50 genes? A hundred genes? My job is to keep an eye on the science and its evolution, and to spread the word as it becomes available. It is not for academics to take away individual prerogative by keeping this information locked up. We're not forcing people to use it, just alerting them to it.' The problem with this,' cautions Till, 'is that ill-informed people may believe that the gene test and subsequent dietary advice must be the "holy grail" of dieting - which is not the case. The addition of gene testing may motivate you to apply good diet principles but it is the principles that will work, not the genetic testing.' Joffe agrees. 'Genetics is the missing link, not the only solution. It needs to be put into context to be effective.'


TUCK IN!
Although more research is needed, the DNA diet can still do more good than harm, says Till. There's nothing risky or faddish about the programmes's eating plans, she points out - 'in fact, they're consistent with traditional dietary principles.' 'We're not giving you drugs to take,' says Joffe. The Atkins diet is far more dangerous! Perhaps the diet's greatest advantage is that - whether the genetic information helps or not - you will end up eating more healthily.' >