Satchidananda PANDA
The scientist researching time-restricted eating (a.k.a. intermittent fasting)
THESE DAYS, IT SEEMS LIKE ALMOST EVERY OTHER PERSON – Jimmy Kimmel, Chris Hemsworth, Jack Dorsey – is singing the gospel of intermittent fasting. But Satchidananda Panda, a professor at the Salk Institute for Biological Studies in the US and one of the world’s leading researchers in the eld of circadian rhythms, actually studies it on a scienti c level, shaping how the public approaches intermittent fasting now and in years to come.
GQ: What are the benefits of time-restricted eating?
Every organ has a clock: there’s a time of peak performance, and there’s a time when they repair and rejuvenate. For example, every day we damage up to onetenth of our gut lining. (The ph of our gut is 1.5, so it’s very acidic. If you put that on a piece of paper, that paper will disappear in a couple of days.) So, each night, our gut replaces somewhere between seven to 10% of its lining. And just as you can’t repair a motorway when traffic’s flowing, you can’t repair gut lining well if there’s food in the system.
GQ: What are some of the misconceptions?
You usually see people eating for eight hours and fasting for 16.
But our studies on mice have shown that eating within a 10-hour window is very similar to an eight-hour window. In fact, 11- and 12-hour windows will also give you a benefit – but not as much. Every nutritionist will come up with his or her own modification: “Skip breakfast.” “Skip dinner.” “Eight hours is the magic number.” But no longterm studies have been done on humans. We think 10 hours is the sweet spot. Your last kilojoule of the day should be at least two to three hours before going to bed. When we eat, blood circulation goes to our stomach to absorb all the nutrients. That raises our core body temperature, which makes it difficult to fall asleep. And two to three hours before going to bed, our melatonin levels rise. That makes our brain sleep, but it also makes our pancreas [which produces insulin to help the body process carbohydrates into energy] go to sleep. There’s not enough insulin to absorb glucose when we eat late at night.
GQ: Has your own diet changed?
My food-and-drink preferences have changed. We see that in all of our studies on time-restricted eating: many people eat fewer snacks.