Have you ever wondered why certain people respond to certain diets, while others don’t? Why some people need to go vegan to achieve their ideal weight, while others do best cavemanning pounds of meat? The reason for these different reactions, according to a new study, can be found in each person’s individual microbiome— or in other words, the collection of microorganisms living in our bodies.

Eran Siegal and Eran Elinav, the Israeli researchers behind the study, monitored more than 1,000 people in their Personal Nutrition Project. They had participants wear devices that monitored their blood sugar every five minutes for a week, as well as keep track of what they ate, so correlations could be drawn. They then studied participants’ feces, in order to determine what bugs were aiding in their nutrition absorption and digestion. Eventually, they were able to generate algorithms which connected specific flora to sugar metabolism. This essentially enabled the scientists to prescribe what should go into a person’s body based on what comes out.


It may be a while before we can send a smear of poop to a lab in exchange for a personalized diet plan. But what’s most immediately applicable from this study is the way it uses information about blood sugar spikes.

This study aims to link blood sugar response to individual gut microbiomes, so that personalized dietary guidelines could be prescribed based on bacteria found in stool samples. But there’s an easier way to approach the study’s findings: accepting the lesson that there’s no such thing as a universally healthy food, and that we can learn which foods work for us by monitoring each one’s effect on our blood sugar. This is something diabetics do every day, in order to determine their insulin dosages, and streamline their own diets.

But even among the non-diabetic population, some people experience a blood-sugar spike when eating carbs, while others don’t. There’s no hard and fast rule, which is why some people get lean on Atkins, while others drop fat eating vegan. 

Short of buying a blood sugar meter and testing your levels for sport, there’s no easy way to perform your own version of Siegal and Elinav’s experiment. But should blood-sugar-testing products for non-diabetics come on the market, would you use them?



  1. Science of Us: The Future of Dieting Is Personalized Algorithms Based on Your Gut Bacteria
  2. Health Magazine: Why You Should Monitor Your Blood Sugar at Home
  3. Web MD: How and When to Test Your Blood Sugar With Diabetes