DNA diets: the new-age weight-loss plan

The answer to all your dieting woes may actually be in your blood, or more specifically your DNA, if the latest nutritional trend is anything to go by.

Personalised nutrition, also known as the DNA diet, is exploding in popularity, with health practitioners now offering services in which they formulate food plans best suited to your genes.

It follows the premise that our genes can reveal a lot about our relationship with food, how they can impact the processing and storing of macronutrients, and even our appetite.

Can’t stop binging on all those leftover Easter eggs? Maybe you can blame it on your genes.

As an example, myDNA co-founder Allan Sheffield says certain fat mass and obesity-associated (FTO) gene variations are tightly linked with obesity, but people with those variations can eat a protein-rich diet and lose more weight than other people on the exact same diet.

“Similarly, the PPARG (peroxisome proliferator-activated receptor gamma) gene can impact how much fat is or isn’t stored for future energy needs, so focusing on polyunsaturated fats becomes more important for people with certain results of that gene,” he explains.

His company tailors meal and fitness plans around people’s DNA, and also uses this data to look at bone health, heart health, sleep, skin ageing and caffeine.

“The recommendations can come back to what we’re consuming in our bodies, and what our bodies do or don’t do with those nutrients. For example, there are genes that impact how vitamin D is converted and transported, which in turn impacts how calcium is used, ultimately impacting bone health,” Mr Sheffield reveals.

While myDNA’s lab is based in Melbourne, Perth clients are signing up and accessing the service through the myDNA Unlocked App, with meal plans delivered as individual recipes, and workout plans including both home and gym workouts.

Perth-based iDNA offers a similar service, with chief executive Sharon Palmer revealing clients are drawn to the science-based and personalised approach to nutrition.

“We don’t make recommendations about anything until we’ve actually looked at someone’s genetics first and we get really good clinical outcomes because it’s not us trying to guess what should be done, the research is that if you have these genetic mutations, these are the risk factors, these are the things that you need to do to adopt so yes we get great clinical outcomes,” she says.

She emphasises iDNA extends beyond offering just a nutritional plan to encompass a whole-health approach, which includes fitness, identifying food intolerances and improving gut health.

Clients provide a swab of saliva and then the raw data is interpreted by practitioners at iDNA and health recommendations are tailored around these results.

“Pretty much anything around our health and wellbeing really sits in our genetics and we’ve just never had the ability to look,” she says.

“Weight loss, weight gain, obesity — the research is really clear, it is not a simple matter of calories in and calories out. People have done the dieting exercise thing to the nth degree and often with very little outcomes and so there’s a lot of genetics that sit behind issues with weight.”

She also says iDNA has very stringent privacy policies and terms and conditions to ensure the sensitive genetic data of clients is safe and secure.

But she cautions those wanting to try DNA dieting to be mindful of online services and to make sure you really know who you’re giving your genetic data to.

“What you really want to do, is if you’re going to be using this around your health, you want to go to people who really know how to interpret it,” she adds.

The science

Nutrigenomics is an emerging field and as such, scientific evidence to support a genetic approach to dieting has not been fully established.

Dr Matthew Piper, a senior lecturer at the School of Biological Sciences at Monash University, compares it to weather forecasting.

“We can generally predict what the weather will be like by knowing historical averages for weather in a given location, this is like giving diet advice from population averages,” he explains.

“We can gain additional accuracy by incorporating wind, rain and using mathematical models — but the outcomes are still far from certain and are couched in terms of probabilities. This is like using genetic markers to give diet advice or responses to medication. It is certainly more accurate than it used to be, but really the outcomes are still associated with a fair degree of uncertainty.”

Dr Piper, who is also head of the Nutritional Physiology and Ageing Research Group at Monash University and has a PhD in biochemistry and molecular genetics, believes it is also problematic that the degree of uncertainty varies in a way that we can’t really predict.

“As with all of these services, the biggest challenge is complexity. Complexity of genomics, complexity of diet and complexity of drugs,” he explains.

“We know of a few instances where changes in single genes have strong effects on health or responses to diet, and in these cases it is easy to predict the outcome from the genetic make-up of the individual. However, for the most part, there are many variants in many genes whose effects are associated with, but not perfectly matched to, health outcomes. This means that the physiological responses to drug and/or dietary advice are still far from being guaranteed,” he adds.

But the upside, Dr Piper says, is that these companies really are using more advanced information to draw associations between an individual’s genetic make-up and a response to a drug or food.

“So while the outcomes are not guaranteed, the technique is still more advanced than general population averages. And so on average, the outcomes will probably be improved when compared to old-school advice,” he says.

Professor John Mamo, director at Curtin Health Innovation Research Institute, says the fundamental question is whether a DNA test can provide any substantial benefit compared to what can already be considered through the plethora of scientific publications that have looked at different components of diet, such as high fat, low fat, high GI and low GI, for health practitioners to provide better or more robust advice. The answer, he says, is rarely.

Professor Mamo, a nutritional physiologist and researcher, says a study of identical twins looking at how they would respond to certain dietary components revealed markedly different results despite them sharing the same DNA.

“So the way we would respond to diet and to food types is an interplay obviously between our genetic ability to handle our living environment, which includes diet. That’s based on thousands of genes and when they do DNA profiling and someone takes a look at the data, what they do is they tend to look at a small handful of genes, sometimes just one gene and from that they try and predict how you might respond to that,” he says.

“When there is a scientific finding which suggests that certain gene types are associated with health and wellbeing, that’s normally done in tens of thousands of people in large population studies, so what I’m saying is drilling down one or several genes to an individual, you can’t do that based on a population study, which is only really saying on average in a large population, if you have this type of genetic make-up, you may have a greater propensity to put on weight or burn less fuel or whatever it might be,” he adds.

The other significant issue, he reveals, is that there are other really important regulators on how your body will respond to diet, with one being your living environment.

“So other things which are really major players in this would include, for example, the level of stress and anxiety that you might have in life. A whole bundle of different hormones, including insulin produced by the pancreas, thyroid hormones, some of the stress-related hormones, they will very much regulate how you metabolise certain components of food in the diet,” Professor Mamo explains.