Eran Segal is a computational biologist at the Weizmann Institute of Science and co-author of “The Personalized Diet.” He studies nutrition, genetics, the microbiome, and gene regulation, looking specifically at how diet affects people differently. Following is a transcript of the video.

Eran Segal: It’s not just what we eat but also: when should we eat?

My name is Eran Segal. I’m a researcher at the Weizmann Institute of Science.

In fact, we’ve done a lot of research in this area. We all have this internal clock that really is responsible for us having various different activities throughout the day and that’s been known for many many years. In fact, a Nobel Prize was just awarded in this year for discoveries related to circadian rhythmicity and several years ago we were the first to show that our gut bacteria, even though they live in the dark of our gut, they also exhibit this circadian rhythmicity.

And really there’s different populations of bacteria that go up and down during the day and because our bacteria are so heavily involved in our metabolism, then it’s really going to have a different effect on us throughout the day. And so in the book we also discuss not just what you should eat, but also we suggest that you should take the same meal and see how you responded to it at different times of the day— before and after different types of activities, such as exercise or sleep or before and after different types of meals. Because really your body in the morning is not the same as your body during later parts of the day and that has to do with your internal clock in the body and also has to do with your gut bacteria which are also really changing their activity throughout the day.

So we’ve done a lot of research to demonstrate that this is a major component that is going to really have an impact on how you respond to food. So it’s not just what you eat it’s also when you eat it.

Eran Segal is the author of “The Personalized Diet.”