I love the logic of this trick!
The brain has two body clocks: one in the “old” and one in the “new” brain.
- The new brain body clock works on natural light patterns. This clock can only shift about 2 hours a day. That’s why it gets thoroughly confused when we cross the planet and the sun is rising at half past midnight.
- The old brain body clock, however, works to make sure you are awake when food is around. If we were always asleep at dinner time, we wouldn’t live very long.
Normally, the new brain is in charge, but there is a way to switch over to the old brain: by throwing our bodies into survival mode.
How do we do that? By starving ourselves.
Okay, that’s a bit dramatic, but apparently it takes about 16 hours of fasting before the old brain body clock will take over, believing food to be scarce.
So if you’re flying from San Francisco to London, take a meal at the usual time in San Francisco, say, breakfast at 8.00am, then don’t eat anything at all until the next appropriate meal time in London, say, breakfast the next day at 8.00pm. Your body will switch onto the old brain and register the body clock time as “breakfast”: exactly what you want.