Imagine no longer having to suffer through painful diets that restrict too many foods. Imagine eating carbs again, eating fats again or eating meat gain, if that is what you’ve been longing for. Imagine that science has finally begun to scratch the surface of the complex question about the optimal diet. Up until now, we’ve always looked for absolutes when it comes to dieting and health. Universal rules that we can all learn and follow. Nutritional guidelines that say everyone needs to avoid this or eat that: kale is good; ice cream is bad, and so on. But when Prof. Eran Segal & Dr. Eran Elinav published their groundbreaking research on personalized nutrition, it caused a media frenzy. Genuine hard science, years of meticulous research, and large-scale data prove it’s the future of dieting.

I met prof. Eran Elinav, who heads a multidisciplinary research group of over thirty immunologists, microbiologists, metabolic experts and computational biologists at the Department of Immunology, Weizmann Institute of Science of Israel.

Professor Elinav, you are the author of a book entitled "The personalized diet”. A book that promises to overturn all that is known about food and to render other diets obsolete. Where did we go wrong? What can you tell us about your book?

The book summarizes 6 years of research performed by my lab and the lab of my partner and colleauge Eran Segal at the Weizmann Institute of Science. It describes several of our major discoveries including the realization that in contrast to our current belief, people react uniquely and differently with their blood sugar rise, even when they consume identical foods. The deep meaning of this discovery is that the dogma of a ‘one size fits all’ dietary approach that has ruled the diet world for half a century needs to be revised to one highlighting unique features of each individual. Indeed in our studies, we combined clinical, background, and microbiome data in generating the first computational-driven method to predict a person’s blood sugar response to any given food, thereby enabling to generate personalized diets to different individuals. We further proved that even short-term utilization of the personalized diet approach normalizes blood sugar in pre-diabetic individuals. We are now testing this approach in long-term studies invovling pre-diabetic, diabetic and gestational-diabetic adults.

You mentioned blood sugar. How does it work and why is it so important to keep it under control?

Blood sugar is a critical feature in human physiology which is impacted by multiple hormonal, metabolic, dietary and other factors. High blood sugar levels over time are not only associated with diseases such as pre-diabetes and diabetes, but also with obesity (through the anabolic effects of insulin), fatty liver and their many metabolic complications including atherosclerosis, ischemic heart disease, and cevebrovascular accidents (stroke). Therefore, normalizing blood sugar levels even before overt diabetes develops is considered an important medical task, but is limited by the paucity of non-medical methods. Given our discovery that post-prandial (post-meal) glucose levels can be uniquly predicted by a combination of person-specific measurable features, we’ve developed a rational way of harnessing nutrition towards blood glucose normalization in healthy and at risk humans. This holds promise in utilizing nutrition in a measurement-based manner to prevent and treat diabetes, obesity, and their many associated cardio-metabolic conditions and complications.

There is also another parameter which, for better or for worse, can determine our state of well-being and which you have used in your research: the activity of the microbiota. Why is this highly populated ecosystem of bacteria that populates our gut, some with positive actions for our health and others “bad", so important?

We have been investigating the host microbiota and its interactions with the host in a variety of human disorders. We and others have shown that the composition and function of our ‘internal’ microbes is important in contributing and driving our health or a variety of ‘multi-factorial diorders’ ranging from infectious, inflammatory, metabolic, neoplastic and even neurological conditions. We’ve also been able to utilize the uniqueness of the microbiome in different individuals as partn of our ‘personalized nutrition’ approach. By massively characterizing a person’s gut microbiome and clinical features we are able to predict his/her blood sugar response to any food.

We have understood that we are all different, with a different genetic heritage, an individual glycemic response and that each of us has a unique composition of intestinal microbiota. Given these variables, it is not surprising that diets and food recommendations designed for everyone wind up not working for anyone. Professor Elinav, how does one develop a personalized custom diet?

In our book, we describe different ways of personalizing diet towards a better metabolic health. The most comprehensive and sophisticated manner relies on our computational system, microbiome measurements and is licensed by the Weizmann Institute of Science that provides a person’s specific analysis, microbiome measurement, a sophisticated perosnalized dietary app, and enables to assess any given food even one that the person has never tested before. In addition, the book describes a more basic (and cheap) way to personalize diet at your home. This is achieved by teh purchase of a simple glucometer at your local pharmacy, and its use at home to test different foods and common meals that are of interest to you and then to change them so to make them healthier for you and less sugar spiking. The exact ways of doing so are described in detail in the book. An even simpler method, to those not interested in even the small skin prick that is part of the glucometer use, invovles assessment of one’s hunger levels in response to different foods. This is less accurate but effective in changing components of one’s diet in a personalized way, as hunger levels are closely associated with the surge of insulin that follows a high sugar pick in our blood.

The book identifies some "rules" for a heathy lifestyle. What are they?

Despite the strong person-specific component of our diet that is central to the approach, we do recognize some general concepts that are still critically important to our metaboic health- caloric balance: we recommend maintaining it. Even a person not spiking his/her blood sugar when eating icecream cannot eat unlimited icecream as calory wise he will end up gaining weight. Likewise, regular exercise, lack of smoking, are important general concepts that are highly recommended to all.

These parameters (glycemic response, activity of the intestinal microbiota) will be investigated for the first time also on children in order to create algorithms to elaborate personalized diets in the pediatric population. How will this data be used and why is a personalized diet in children important?

While so far we’ve focused our efforts on personalized diet in adults as means of improving sugar control and its health consequences, we’ve not studied the important children population. This is important because children are rapidly becoming a major part of the obesity/diabetes epidemic, and feature an alarming risk for these disorders throughout the world, with no current solution. We know that childhood obesity and diabete also predispose to metabolic disease later in life. We therefore embarked on the CAPRII study (the first international pilot study conducted by the Schneider Children's Medical Center and the Weizmann Institute of Science of Israel together with the Department of Translational Medical Sciences of the University of Naples "Federico II" in Italy), aimed at developing personalized nutritional tools in children for the first time. We focus on personalization of the Mediterranean Diet that is generally concieved to be healthier, in two mediterranean populations in southern Italy and Israel. We hope to generate knowledge that would enable to personalize diet in children in a way that will be effective and compatible with follow up for long periods of time.