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.

Free course: Improve your metabolic health

Get our free email course on how glucose, nutrition, exercise, sleep, and measurement can help you build habits that support better energy and long-term health: ⁠⁠⁠⁠⁠⁠⁠⁠⁠https://levels.link/wnl⁠

🎙️ 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58:11 Early findings from her unpublished aging study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

Find us on YouTube: ⁠⁠⁠⁠https://youtube.com/levelshealth?sub_confirmation=1⁠⁠⁠

👋 Who we are:

Levels helps you understand your metabolic health with personalized data, expert guidance, and tools that connect your daily choices to measurable changes in your body. Our goal is to help you make better decisions about food, exercise, sleep, and long-term health.

Look for new shows every month on A Whole New Level, where we have in-depth conversations with thought leaders about metabolic health.