#306 - Does Intermittent Fasting Actually Work? | Dr. Courtney Peterson & Mike Haney

Is intermittent fasting biohacker wellness hype or legit health intervention? Some studies show real benefits, others find nothing, and the occasional headline calls it bad for your heart.

Dr. Courtney Peterson has spent nearly two decades running some of the field's most tightly controlled feeding trials, and her data points to a clear pattern: there is a real effect to a restricted eating window, but when you eat may matter as much as how long you fast. Her studies found that eating in a short window early in the day lowers blood pressure and improves insulin sensitivity, even without weight loss. A physicist by training, she brings that same rigor to a field built mostly on people's own food diaries.

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🎙️ About the Guest:

Dr. Courtney Peterson is an Associate Professor of Nutrition, Harvard T.H. Chan School of Public Health. She holds a PhD in physics from Harvard and leads clinical trials on intermittent fasting, meal timing, and circadian rhythms.

📍What Dr. Courtney Peterson & Mike Haney discussed:

• 0:00 Introduction
• 02:39 The three types of intermittent fasting
• 05:29 The 2012 mouse study that started the field
• 11:24 Why fasting works through appetite, not extra calories
• 13:48 Her six-hour study: lower blood pressure, no weight loss
• 25:34 Why results depend on who's being studied
• 28:45 The shift worker whose health got worse
• 36:45 Her theory: timing over fasting length
• 43:08 Heart attacks, blood pressure, and the body's clock
• 45:55 The camping trip that reset people's body clocks
• 58:11 Early findings from her unpublished aging study
• 1:08:16 Should you eat ice cream for breakfast?

🔗 Helpful Links:

• Time-Restricted Feeding without Reducing Caloric Intake Prevents Metabolic Diseases in Mice Fed a High-Fat Diet (Hatori et al., 2012) — https://doi.org/10.1016/j.cmet.2012.04.019
• Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes (Sutton et al., 2018) — https://doi.org/10.1016/j.cmet.2018.04.010
• Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans (Jamshed et al., 2019) — https://doi.org/10.3390/nu11061234
• Calorie Restriction with or without Time-Restricted Eating in Weight Loss (Liu et al., 2022) — https://doi.org/10.1056/NEJMoa2114833

Watch the conversation: https://youtu.be/dKauIgX3IH4

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