Andrew Huberman: Professor of Neurobiology and Ophthalmology at Stanford School of Medicine and host of the Huberman Lab Podcast. This is a solo episode with no outside guest.
What this episode covers
In this solo episode, Andrew Huberman explains the mechanisms and tools of time-restricted feeding (intermittent fasting). He argues that when you eat is as important as what you eat, because food sets metabolic 'conditions' that influence clock genes, liver health, inflammation, gut microbiome, hormones and fat loss. He leans heavily on Satchin Panda's landmark mouse and human work to recommend an roughly eight-hour daily feeding window anchored to daytime, no food for the first hour after waking, and none for two to three hours before bed. He also covers glucose-clearing tools (walks, exercise, berberine, Metformin), what breaks a fast, salt for fasting comfort, and how to personalize a schedule.
Recommended on this episode
Also referenced (named, not recommended)
Metformin
Metformin
“These are so-called glucose disposal agents, glucose, disposal agents, such as Metformin, which is a prescription drug or berberine”— Andrew Huberman
Berberine
Berberine
“berberine, which is an over the counter substance will lead to very dramatic reductions in blood glucose”— Andrew Huberman
Big reveals from this episode
- Higher resting blood glucose predicts mortality in humans and primates, but the OPPOSITE is true in mice, a 180-degree species difference Huberman flags as a translation warning.
- The famous eight-hour feeding window was not chosen for biology, but because a grad student's significant other forbade them being in the lab longer than 10-12 hours.
- Roughly 80% of the genes in your body and brain run on a 24-hour cycle, and meal timing helps entrain those clock genes.
- In elite cyclists, time-restricted feeding significantly LOWERED free testosterone, but also lowered cortisol, partly offsetting the effect.
- Drifting your feeding window a couple hours on weekends jet-lags your metabolism and can take two to three days to recover from.
- Huberman discovered via continuous glucose monitor that a sauna spikes his blood glucose as high as a meal, due to dehydration concentrating blood sugar.
- Very short four-to-six-hour eating windows produce health benefits but often cause overeating and even weight gain, unlike eight-hour windows.
Worth remembering
- Most people underestimate their feeding window by one to two hours because of small 'cheats' like a glass of wine or a tea with a cookie.
- Even one gram of sugar after a full dinner can disrupt circadian genes tied to fasting and sleep; a half glass of wine breaks your fast.
- A simple 20-30 minute walk after dinner accelerates glucose clearing and the transition from fed to fasted state.
- After eating, food takes about five to six hours to clear, so you are not truly 'fasted' just because you stopped eating.
- Cinnamon, plus lemon and lime juice, can mildly lower blood glucose via acidity.
- A pinch of sea salt in water can relieve the shakiness and hunger of fasting because neurons run on electrolytes; caffeine excretes sodium.
- Brown fat (between the shoulder blades) correlates with absence of non-alcoholic fatty liver disease and can be boosted by cold exposure and fasting.
- Fats slow gastric emptying, liquids speed it, so meal composition changes how fast you enter a fasted state.
- Whether one peanut breaks your fast is fully contextual, depending on prior meals and where you are in your circadian cycle.
- Satchin Panda was one of three co-discoverers of the melanopsin cells in the eye that set the central circadian clock.