190 The Science of Fasting & How to Use It for Sharper Thinking | Dr Tom Buckley

When did you last actually let yourself feel hungry? Not the "due for a snack" kind. Properly, deliberately hungry, on purpose. If you can't remember, you're not alone. Now imagine using that discomfort as a lever instead of avoiding it.

Every reflexive snack, every meeting that runs straight into the next, every bite you take before your body even asks for it keeps you running on one setting. You never give your body the signal to switch fuel sources, sharpen your focus, or clean house at a cellular level. The fog, the afternoon slump, the stubborn weight that won't shift: that's the bill for never stopping.

Dr Tom Buckley has spent more than 22 years reading the bloodwork of Performance Intelligence's executive clients, translating what's happening inside hundreds of high performers into how they eat, train, and lead. He's back on the podcast to explain what fasting actually does inside your body, why the meal you were told never to skip has a cereal company to thank for that reputation, and how two nights a week without dinner might be the highest-leverage habit in your week.

You could keep running on constant fuel and wonder why your energy never settles. Or you could learn to use hunger as a lever instead of an enemy.

03:35 The fat that's easiest to shift, and where it sits

05:41 Ghrelin, leptin and the people who never feel full

09:03 Three fuels, one easy habit: why carbohydrate wins by default

10:27 Metabolic flexibility: the skill Western living has trained out of us

16:08 The story that's driven Dr Tom for 35 years

21:47 What fasting switches off first

22:47 Ketones: the fuel that skips the insulin queue

25:13 Fasting and the new GLP-1 drugs are chasing the same biology