How to Lose Weight, Boost Energy, & Live Longer with Intermittent Fasting | Mel Robbins Podcast

KEYPOINTS

• 01

  Fasting as a healing state switched on by low blood sugar

  Dr. Mindy Pelz, author of Fast Like a Girl, describes fasting as a state the body reaches only by going without food long enough for blood sugar to drop. In her account, that triggers repair responses: burning fat, sharpening the brain, quieting hunger, improving sleep, easing pain and slowing aging. Mel frames this first episode of a two-part series as the science; part two covers how-to and protocols for women.

• 02

  Two energy systems, like a hybrid car

  Pelz describes a "sugar burner" system that runs on food and a "fat burner" system that kicks in when blood sugar falls, usually 8 to 12 hours after eating. Moving between the two is called metabolic switching. She says people with poor metabolic health stay stuck burning sugar and never reach the repair processes, and cites a figure that only about 12% of Americans are metabolically fit. Her evolutionary explanation is feast-famine cycling: early humans had no fridge or DoorDash.

• 03

  It's about when you eat, not what

  Pelz says fasting isn't a diet because you can keep any eating style and simply compress it into a window. She cites research suggesting that eating within 8 to 10 hours a day can reverse metabolic damage, even from fast food. On "keto" products, her advice is to skip the label debate and eat "nature's carbs," meaning vegetables, fruit and foods that grow from the earth, over anything made in a factory.

• 04

  Why cravings fade, according to her

  Pelz gives three reasons. Fast-food blood-sugar spikes crash low and trigger hunger every few hours, and longer gaps break that cycle. Ketones made while burning fat travel to the brain and switch off hunger. Fasting also shifts the gut microbiome, and she says organisms like candida drive sugar cravings. She adds that ketones raise GABA, a calming neurotransmitter, and describes landing after an 18- to 19-hour flight fast feeling calm and not hungry.

• 05

  How the research is characterized

  Mel says a 2019 New England Journal of Medicine review of more than 85 studies recommended intermittent fasting as a "first line" intervention for obesity, diabetes, heart disease, neurodegeneration and cancer, with anti-aging effects. That's how she and Pelz summarize the paper. Pelz also says much fasting research comes from people observing Ramadan, notes Hippocrates wrote about fasting, and argues that the media amplifies negative stories because no industry profits from fasting.

• 06

  Who shouldn't fast, and when to involve a doctor

  Pelz says fasting is not for pregnant women. Nursing mothers should keep fasts under 15 hours because detox byproducts may pass into breast milk. It's also not for anyone with an eating disorder or whose food challenges it could trigger. People with diabetes or heart disease should fast only with their doctor involved, and Mel adds that anyone on psychiatric or ADHD medication should check with their doctor.

• 07

  The clock starts with your last bite or sip

  Wine counts, and sleep counts toward the fast. Black coffee is fine as long as nothing in it spikes blood sugar, so creamer and sugar are out, and a Frappuccino definitely doesn't count. Full-fat cream usually works, she says, because fat stabilizes blood sugar.

• 08

  The six fasting lengths, as she describes them

  12–16 hours: glucose and inflammation fall and growth hormone, which she says declines after 30, rises. 17 hours: autophagy, cells clearing out damaged parts, with Pelz saying it can eliminate rogue cells. 24 hours: a "gut reset," citing MIT work on intestinal stem cells. 36 hours: a "fat burner" reset aimed at stored belly fat. 48 hours: a "dopamine reset" with more receptor sites and lower anxiety. 72 hours: an "immune reset" based on Valter Longo's research at USC.

• 09

  Start small and give it 90 days

  Fasting gets easier with practice. Pelz compares it to marathon training, so don't open with a 36-hour fast. For belly fat, she says to do 12 to 15 hours consistently and give it about 90 days. Many in her community use 17-hour fasts after a vacation of overindulging. Longer claims, like happiness rising for weeks after a 48-hour fast, come from stories her community shares rather than controlled trials.