Why the same healthy diet is impossible for everyone – study

Scientists have discovered how individual the metabolic reaction of different people to the same foods is. They hope that in the future it will be possible to develop a separate diet for each person.

Why the same healthy diet for everyone is impossible - research 6687

People's reactions to the same food can vary greatly. The authors of the new study, which was published in Nature Medicine, are confident that there is no universal diet that is beneficial for everyone; we need to look for ways to individualize the diet.

The new study involved 1,102 healthy volunteers. For two weeks they received the same diet, and scientists observed changes in their metabolism. Participants' sleep, hunger, and physical activity were also assessed, and gut microbiome samples were taken.

The main indicators that the study authors monitored were blood glucose, insulin and triglyceride levels. High levels for all three substances may indicate a risk of obesity, triglycerides are a potential risk factor for cardiovascular disease, and glucose and insulin are markers of diabetes risk. The level of these substances in healthy people after an identical meal in extreme cases could differ by 10 times.

Significant differences were found even among the pairs of identical twins who participated in the study. The weak influence of genetic predisposition on how people react to food came as a surprise to scientists. They concluded that looking for a “gene-matched diet” is a misleading concept.

The identical twins in this study had only a third of their gut microbiomes the same. Scientists expect that in the future the role of gut bacteria in the human body's response to food will be better determined. They also expect that interventions at the level of the gut microbiome will help fight obesity and promote health.

The timing of meals also played a role for each participant individually. The same food for breakfast and lunch caused different reactions in some people, but no such difference was found in others.

The scientists emphasized that despite such diversity, individual participants’ daily reactions to food were usually comparable, becoming predictable. They point out that this feature may make it possible to predict how a particular person will react to different products in the future.

If the study participants’ bodies “didn’t like” the foods, the scientists found that levels of inflammatory markers increased in their blood. The researchers called this phenomenon “dietary inflammation.”  

“Our findings suggest that it may be possible to improve weight management and health through more personalized nutrition designed to avoid unhealthy inflammatory responses to food,” Professor Tim Spector, a genetic epidemiologist at Imperial College London and co-author of the study, wrote in The Conversation.