People’s metabolic response to the same food varies so differently that a one-size-fits-all approach will never work, new research has found.
Medically reviewed by Dr Louise Wiseman MBBS, BSc (Hons), DRCOG, MRCGP and words by Annie Hayes
Mediterranean, flexitarian, Keto, Paleo, there is no shortage of diets to sign up to – but which is the best? It depends who’s asking, because there is no such thing as a one-size-fits-all approach to healthy eating, according to a new study from King’s College London.
People respond to food in such different ways that each person needs a personalised eating plan, the research – which set out to examine the effects of genetics, the microbiome and lifestyle factors on metabolism – revealed. In other words, what constitutes a healthy diet for one person can actually be unhealthy for another.
Which is the best diet for me?
The study, which was published in the journal Nature Medicine, found the perfect diet doesn’t exist. For two weeks, scientists fed 1,102 healthy people identical meals and measured their metabolic responses. ‘The researchers looked at the differences in people’s blood glucose (sugar), insulin, and triglyceride (fat) levels,’ explains Aisling Moran, nutritional scientist at Thriva. ‘This is because raised blood sugar and fat levels can lead to inflammation – which is linked to an increased risk of weight gain, diabetes, and heart disease.’
There were huge variations in people’s response to identical meals, with some results varying tenfold.
There were huge variations in people’s response to identical meals, with some results varying tenfold. ‘Some people had quick and prolonged increases in their blood sugar and insulin levels, which is linked to an increased risk of weight gain and diabetes,’ says Moran. ‘While others had fat that stayed in their blood for hours, which is linked to an increased risk of heart disease.’
Interestingly, this study included identical twins who also responded very differently to the same foods. ‘This suggests that genes don’t play as big a role as initially thought,’ she continues. ‘This is positive – if your genes were to play a bigger role you’d have less control over your response to food, and ultimately your risk of disease.’
Sleep, exercise and gut health
The researchers also tracked the volunteers’ sleep, exercise and hunger levels over the course of the two weeks. They measured participants’ circadian rhythm (sleep-wake cycle) and took stool samples to analyse their gut microbiome (the types and amounts of microbes in their gut).
It was these factors that played the biggest roles in determining how healthy a diet is for an individual. ‘Meal timing was also an important factor,’ adds Moran. ‘For example, some people were much better at metabolising foods at breakfast, for others the time of day didn’t matter.’
This doesn’t mean that you should abandon all fruits and vegetables and succumb to a diet of junk food and fizzy drinks (the ill-effects of which have long been demonstrated in nutritional research). By adopting a more personalised approach to our diet, we’ll be better placed to stay healthier for longer.
‘What’s really exciting about this research is that factors like sleep, gut diversity, exercise, and meal timing are all things we have control over,’ she continues. ‘If we have access to this type of information about ourselves, we can make positive changes to lower our risk of weight gain, diabetes, and heart disease.’
So, could the results of this study see a marked shift in the way we approach ‘healthy eating’ going forward? ‘While this study and the findings are really impressive, this level of personalised nutrition is still a relatively new concept and more research is needed,’ Moran says.