Have you ever wondered why you can’t lose weight on a fad diet but your friend can? Maybe you ditched the carbs or tried a trending nutrition plan but instead of weight loss, you experienced weight gain.

Your weight-loss woes may be answered with a simple blood test.

“Personalised nutrition” is an approach many nutritionists take with an increasing number of practitioners turning to DNA testing to tailor their diets specifically for the individual.

The general premise is that there is no “one-size-fits-all” when it comes to diet plans and exercise programs. Genes, microbiome, lifestyle habits, occupations and environments differ greatly from one person to the next. Health experts say, so should their diet and exercise routines.

New research from King’s College in London and Massachusetts General Hospital in the United States demonstrates the current dietary guidelines and food pyramid nutrition advice provided by dietitians is far too simplistic. The results suggest a personalised nutrition model is more likely to yield better long-term overall health outcomes.

More than 1,000 people (mostly twins) participated in the recent study that measured how makers in blood samples such as sugar, insulin and fat change after eating a specific diet. Data on physical activity, sleep, hunger and gut microbiome was also collected.

The test results found there was a wide variation in blood responses to the same meals regardless of whether they contained carbs or fat.

Some participants, for example, experienced rapid and prolonged increases in their blood sugar and insulin levels. Both of which are associated with weight gain and type 2 diabetes.

The results of other participants showed an increased risk of developing heart disease based on their high and lingering fat biomarkers after a meal.

According to King’s College, the variations in test results can only be partly explained by the participant’s genes as even the identical twins who share the same genetic make-up and family history and experience the same environment had different responses to identical foods.

Personalised nutrition: the latest approach to encourage weight loss

For many nutritionists, personalised nutrition is the way forward to not only to assist weight loss but to improve overall health.

Clinical nutritionist Sarah Appleford says this is not a novel approach.

“Designing an individually-tailored nutrition plan that takes into account the client’s blood test results, microbiome makeup, medical history, family history and lifestyle is at the core of our practice”, she says.

“There is no one diet that’s right for everyone. Of course, there are standard dietary and lifestyle changes we can make to improve our overall health, like stay hydrated and move regularly. However, if you want to work on specific goals and achieve sustained results you have to look more closely at the individual facets of that person.”

Some researchers, however, warn against personalised nutrition and the gaps in the evidence.

“Scientists working in this area have expressed concerns about over-promising, individually as well as through institutional guidelines and statements,” states Jose M Ordovas, co-author of the review ‘Personalised Nutrition and Health published in the British Medical Journal.

The researchers’ state “much research is needed” for personalised nutrition to gain scientific credibility, especially when it comes to using genetic testing to inform a specific diet.

“Regardless of the scientific evidence, if you’re not seeing the results and not improving your health you need to make a shift. That might include stepping away from the standardised government guidelines and taking a personalised approach to your own health,” says Sarah.