That is, there’s no one diet guaranteed to be healthy for everyone.

By Catherine Orda | Photo by Brooke Lark /Unsplash

A study by scientists Eran Segal and Eran Elinav is revolutionizing the way we look at healthy diets.

The methods and results of the study, published in the 2017 book The Personalized Diet, point to the inherent flaws of the current nutritional paradigm, which operates in a sort of straitjacket of universal health principles.

Now believing in these health rules isn’t necessarily wrong—we all know that smoking does kill and that excessive fast food consumption can lead to obesity and/or heart failure. But to a population of figure-obsessed, calorie-conscious individuals, this has also meant staunch adherence to and a relentless search for the healthy diet—a one-size-fits-all program that leads to weight loss and generally better health.

The pursuit for these diets have led to the creation of a cottage industry of sorts, with countless articles and books convincing you that eating food A will make you lose weight, and eating food B will make you gain it. You’re probably familiar with (or you may have even tried) at least one of these diets: ketogenic, South Beach, Atkins, Alkaline, and the like. But do any of these actually work?

It’s not that Segal and Elinav are saying that none of these diets are effective, their message speaks more to the effect of informed skepticism. Which is to say that you probably shouldn’t waste your time trying each one of these diets because even if they work for some people, it’s possible that they may not work for you. This is where the idea of a personalized diet comes in.

Segal and Elinav monitored the blood sugar levels of 1,000 people over the course of a whole week. They found that white bread induced almost no effect on the blood sugar levels of some people while inducing huge spikes in other people. The point is, what may be bad for some people may not necessarily be bad for you.

The researchers argue that the reason we haven’t found the most ideal diet for humans is that there isn’t one. As they see it, it seems that we’ve been asking the wrong question. Instead of obsessing over popular diets and feeling betrayed over the underwhelming effects of say, the Master Cleanse, Segal and Elinav suggest that we ponder these questions instead: What is the best diet for me? What if our nutrition needs to be personally tailored to our unique makeup?

Of course, this is just one ostensibly revolutionary study. And a relatively young one at that—with some critics having expressed some reservation in acknowledging the game-changing potentials of the book. Nevertheless, here are some of the things we learned:

Blood Glucose Levels Are Everything

Our blood sugar levels are essential—at least when it comes to tracking how what we eat affects our body. High glucose levels promote hunger and weight gain, and so by focusing on our blood glucose levels (which change after every meal), it will, in turn, be easier to tell which foods increase risks of hunger and weight gain.

Eating White Bread May Not Always Be a Bad Idea

It turns out that the weight gain-inducing reputation of white bread is a lot more nuanced than we were led to believe. Segal and Elinav monitored the blood sugar levels of 1,000 people over the course of a whole week. They found that white bread induced almost no effect on the blood sugar levels of some people while inducing huge spikes in other people. The point is, what may be bad for some people may not necessarily be bad for you. The authors conclude that this condition is true for every single food that they tested.

It’s Not Just About the Food, It’s Also About the Person Eating It

Each person has different foods that spike their blood glucose levels. For instance, some participants in the experiment were found to have spiked for ice cream but not for rice; while it was also found that others spiked for rice and not for ice cream. This result of the experiment have led the authors to conclude that responses to food are personal, and diets that maintain normal blood glucose levels must therefore be personally tailored to the individual. Which is to say that your dietary failures may not have been your fault. In a TED talk about their book, Segal says your diet may have failed simply because it didn’t take information about you as an individual into account. The responses to food are personal, so dietary advice must also be personal.

Good Diets and Bad Diets

Segal and Elinav developed an algorithm that can supposedly predict an individual’s blood sugar response to different foods. They tested out this algorithm by designing two diets with the same calorie count: a good diet (which included ice cream) and a bad diet. Sure enough, it was found that a participant’s blood sugar reached abnormally high levels after eating the bad diet, and that they went back to a normal level (without a single spike throughout the whole week) after eating the good diet. Again, this points to the idea that dietary advice must be personal.