Wendy Kopp, the CEO and co-founder of Teach For All, believes she’s “figured out jet lag.” The solution sounds simple, but makes sense when you consider why jet lag happens.

Wendy Kopp, who came up with Teach For America as a senior at Princeton University and is the CEO and co-founder of Teach for All, said she used to struggle with severe jet lag all the time, particularly when traveling from east to west. But she recently told CNBC she tried a jet-lag hack that was recommended to her, and it’s worked like a charm.

“The trick is: You don’t eat on the plane, and when you land, you go on a run before you eat anything,” Kopp said. “For many, many years, I didn’t do it, and I finally just resorted to it and I’ve not had jet lag since.”

The logic here is to reset the body’s natural rhythms through fasting and immediate physical activity to align one’s internal clock with the new local time before introducing any food. And that does seem to track well with why jet lag happens, and what many do to get over it.

Why jet lag happens—and what you can do to fight it

Jet lag disorder, according to the Mayo Clinic, is a physiological response to rapid travel across multiple time zones that temporarily throws off the body’s circadian rhythms—the internal clock that governs sleep, alertness, digestion, and hormonal cycles. The brain coordinates these rhythms based on environmental cues, primarily light and darkness, but when you cross time zones quickly, your internal clock remains set to your original location, and all the body’s systems like sleep and hunger fall out of sync with the new environment. Jet lag can cause a general feeling of being unwell, and include symptoms like fatigue, insomnia, and digestive issues.

Notably, traveling east is often harder on the body than traveling west, as Kopp often experienced herself, because it forces the body to sleep earlier than it’s accustomed to; conversely, traveling west is generally easier to adapt to.

Kopp’s approach, while it hasn’t been formally studied, does align with some emerging research on circadian biology. Fasting during travel and delaying the first meal until arrival may help shift the body’s “food clock,” a secondary circadian system that responds to eating times. And studies suggest meal timing can influence how quickly the body adjusts to a new time zone: Some experts recommend eating only light meals during flights, but then doing activities in your local time zone like eating and sleeping as soon as you arrive, to help reset internal rhythms.

Exercise, especially outdoors, is also recommended for combating jet lag. Physical activity can help synchronize the body’s circadian rhythms, particularly when combined with exposure to natural light.

While Kopp’s trick may prove useful, there are other things you can do to help fight jet lag when you travel, like adjusting your sleep schedule, staying hydrated, avoiding alcohol and caffeine (which can mess with your sleep and hydration), and limiting naps after you arrive to encourage more nighttime sleep. Some experts also recommend taking melatonin in small doses, but you should always consult your physician or a doctor before taking any new supplements.

This story was originally featured on Fortune.com