Laura: Alright, Sophia, pop quiz. What’s the one piece of health advice we’ve all heard a million times? Sophia: Oh, that’s easy. ‘Eat less, move more.’ It’s the gospel of every January 1st resolution, every fitness magazine, every well-meaning doctor’s visit. Laura: Exactly. It’s simple, it’s logical, and according to our book today, for about half the population, it’s fundamentally wrong. Maybe even dangerous. Sophia: Wait, what? Dangerous? That’s like saying water is dehydrating. How can the most basic health rule be wrong? Laura: That is the provocative question at the heart of the book we're diving into today: Fast Like a Girl by Dr. Mindy Pelz. And Dr. Pelz comes from a really interesting place—she’s a Doctor of Chiropractic and a functional medicine expert who got into this field after her own health crisis as a teenager was solved by diet, not by conventional medicine. Sophia: Okay, so she’s coming at this from outside the standard medical playbook. That makes sense. Laura: Completely. And this book has been massively popular, getting rave reviews from so many women who feel like it finally 'gets' them. But it has also sparked a lot of debate in the scientific community for some of its bolder claims. Which is exactly why we need to talk about it. Sophia: I love that. A little bit of controversy makes for a much better conversation. So, if ‘eat less, move more’ is the big lie, what’s the truth? Is it just that we all lack willpower? Because some days, it really feels that way. Laura: That’s the first myth she wants to bust. It is not about willpower. In fact, the book’s first big idea is a chapter titled, "It's Not Your Fault."

Sophia: Oh, I like the sound of that. Absolve me of my dietary sins, Laura. Tell me why it’s not my fault. Laura: Well, Pelz argues that many popular diets fail because they work against our body's fundamental design, especially for women. Let's take the biggest one: calorie restriction. The whole 'calories in, calories out' model. Sophia: The one I've been trying and failing at since I was sixteen. Yes, I'm familiar. Laura: Pelz points to this horrifying but fascinating study from the 1960s, the Minnesota Starvation Experiment. Researchers wanted to understand the effects of famine to help with post-war relief efforts. So they took 36 healthy, psychologically stable men and put them on a severely calorie-restricted diet, about 1,500 calories a day. Sophia: That doesn't even sound that low by today's diet standards, which is already a scary thought. What happened to them? Laura: It was a disaster. Physically, they lost weight, of course. But the psychological toll was catastrophic. These men became completely obsessed with food. They would read cookbooks for hours, dream about food, and some even started hoarding little scraps. They became anxious, depressed, and socially withdrawn. Their entire personalities changed. Sophia: That is terrifying. It sounds less like a diet and more like a psychological torture experiment. Laura: It basically was. And here’s the kicker. When the experiment ended and they were allowed to eat freely again, they didn't just regain the weight they lost. They quickly regained it all, plus an extra 10 percent. Their bodies had become hyper-efficient at storing fat, and their metabolisms had crashed. Sophia: Wow. So by starving themselves, they essentially trained their bodies to become better at gaining weight in the future. That explains... a lot about yo-yo dieting. Laura: Exactly. Pelz’s point is that this isn't a failure of willpower; it's a biological adaptation. Your body thinks it's in a famine and does everything it can to survive. And this is just one of the five "diet failures" she outlines. Sophia: What's another one? I’m guessing the low-fat craze of the 90s has to be in there. My mom's fridge was a sea of beige, fat-free products that tasted like cardboard. Laura: You nailed it. The war on fat. We were told fat was the enemy, so food companies took it out and replaced it with what? Sugar, chemicals, and a host of artificial ingredients. We swapped healthy fats for processed carbs. Sophia: And we all got sicker. I've seen the charts. Obesity rates just skyrocket from the 70s onward. Laura: Precisely. This led to a massive rise in insulin resistance. Our cells got so overwhelmed by the constant flood of sugar that they just stopped listening to insulin, the hormone that's supposed to shuttle sugar into the cells for energy. When the cells are full, that excess sugar has to go somewhere. Sophia: Let me guess. It gets stored as fat. Laura: It gets stored as fat. And this is happening under the guise of "healthy" low-fat eating. So you have women diligently counting calories and eating fat-free yogurt, wondering why they feel exhausted, anxious, and can't lose weight. It's a setup for failure. Sophia: Okay, I'm convinced. The system is rigged. So if the old models are broken, what's the new one? Where do we go from here? Laura: This is where the book pivots from the problem to the solution. Pelz argues we need to look at a much older, more primal system. And here, the key isn't about what you eat, but when you eat. It’s all about flipping a switch in your body.

Sophia: A switch? That sounds suspiciously simple. What is this metabolic switch? Laura: It’s called metabolic switching. Think of your body as a hybrid car. It has two fuel tanks. The first one is the sugar-burning tank, which runs on the glucose from the food you eat. This is what most of us run on, all day, every day. Sophia: Right, the three-meals-a-day-plus-snacks model. My sugar tank is never empty. Laura: Never. But there's a second, more powerful, and much cleaner-burning fuel tank: the fat-burning tank. This one runs on ketones, which your body produces when it breaks down its own stored fat. Fasting is the key that unlocks that second tank. Sophia: So fasting isn't about starving yourself, it's about convincing your body to switch fuel sources? Laura: That's the reframe. And it’s a primal design. Pelz uses this great analogy of our hunter-gatherer ancestors. Picture them waking up in the morning. There's no fridge, no pantry. They are, by default, in a fasted state. Sophia: They can't just grab a granola bar and run out the door. Laura: Exactly. So their bodies flip the metabolic switch. They start running on ketones from their stored fat. This does two amazing things. First, it provides a steady stream of energy. Second, ketones are incredible for the brain. They create mental clarity and focus—perfect for tracking a woolly mammoth or finding the right berry patch. Sophia: So that feeling of brain fog we get when we're 'hangry' is actually a modern problem. Our ancestors would have been sharpest when they were hungry. Laura: That’s the idea. Then, after a successful hunt, they would feast. This would flip the switch back to sugar-burning and trigger something called mTOR, which is the body's 'growth and build' mode. So their life was a natural rhythm: fast and repair, then feast and build. Sophia: And we've lost that rhythm. We're stuck in 'feast and build' mode 24/7. Laura: Constantly. We never give our bodies a chance to run the cleanup crew. And that cleanup process has a scientific name: autophagy. Sophia: Autophagy. I've heard that word thrown around. It sounds very technical. What is it, in simple terms? Laura: Think of it as your cells’ internal Roomba. When you fast for about 17 hours or more, you trigger autophagy. Your cells start identifying old, damaged, or dysfunctional parts—misfolded proteins, worn-out mitochondria, even pre-cancerous cells—and they gobble them up and recycle them. It’s a deep cellular detox. Sophia: Okay, so our modern lifestyle of constant eating is like never letting the Roomba run. The house just gets messier and messier with cellular junk. Laura: That's a perfect analogy. And this isn't just a theory. She cites a study from the Journal of the American Medical Association that looked at women who had gone through breast cancer treatment. The women who fasted for just 13 hours or more overnight had a significantly lower chance of cancer recurrence. Sophia: Wow. Just by extending their overnight fast, they were essentially turning on their body's own cancer-fighting cleanup crew every single night. Laura: That's the power she's talking about. It’s not a magic pill; it’s activating a healing system that's already built into our DNA. Sophia: This all sounds incredible. But I have to ask the question that's probably on every woman's mind right now. I know people, friends of mine, who've tried intermittent fasting and felt absolutely awful. They had hair loss, crippling anxiety, their cycles went haywire... What gives? If it's so natural, why does it sometimes backfire so badly? Laura: That is the million-dollar question. And it brings us to the absolute core of this book, the part that is both its most unique contribution and, for some, its most controversial.

Sophia: I'm ready. Lay it on me. Laura: The answer, according to Dr. Pelz, is that women cannot and should not fast like men. A one-size-fits-all fasting schedule—like the popular 16:8 or 18:6 methods—can be a hormonal disaster for a female body. Sophia: Why? What’s so different? Laura: In a word: hormones. A man's hormonal system is relatively stable day-to-day. A woman's is a symphony, with different hormones taking the lead at different times of the month. And these hormones have very different needs. To make this real, Pelz tells the story of a patient she calls 'Bridget'. Sophia: Okay, let's hear about Bridget. Laura: Bridget is a classic high-achiever. A type-A tech executive in her early 40s, super stressed, running on coffee and ambition. She starts intermittent fasting because all her male colleagues are doing it and raving about the mental clarity. She does 18-hour fasts every day. Sophia: And at first, she probably felt amazing. Laura: She did! For about six months, she felt incredible. She was productive, energetic, losing a bit of weight. She thought she'd found the holy grail. But then, things started to go wrong. She started getting heart palpitations. Crippling anxiety out of nowhere. She couldn't sleep. And the final straw—her hair started falling out in clumps. Sophia: Oh my god. That's terrifying. She must have thought she was seriously ill. Laura: She went to her doctor, who ran a bunch of tests, found nothing, and told her to just stop fasting. But Bridget had a gut feeling that fasting wasn't the enemy; it was how she was fasting. She eventually found Dr. Pelz's work. Sophia: And what was the diagnosis? Laura: The diagnosis was that she was fasting against her own biology. She was pushing her body into a high-stress, fasted state during the parts of her cycle when her body was desperate for safety and nourishment. Specifically, the week before her period. Sophia: Whoa. So the timing is everything. It's not just if you fast, but when in your cycle you do it. Laura: It's the whole game. Pelz breaks it down very simply. For the first half of your cycle, when estrogen is dominant, your body is more resilient. Estrogen loves fasting. It can handle longer fasts, it helps with insulin sensitivity, you feel great. That's the time to lean into those 17-hour autophagy fasts. Sophia: Okay, that's the 'Power Phase' she talks about. Laura: Exactly. But in the second half of the cycle, especially the week before you bleed, progesterone is the star of the show. And progesterone is a very different beast. It's the 'calm and nesting' hormone. It needs a little more glucose to be produced. It's highly sensitive to stress. Sophia: And a long fast is a form of stress on the body. Laura: A major form. So if you're doing long, aggressive fasts when your body is trying to make progesterone, your body panics. It thinks, "Famine! This is not a safe time to be fertile!" So it tanks your progesterone production. And what are the symptoms of low progesterone? Anxiety, poor sleep, mood swings, and yes, hair loss. Sophia: Bridget's exact symptoms. That is a massive 'aha!' moment. We're not just smaller versions of men; we are operating on a completely different hormonal OS. Laura: A different operating system. That’s the perfect way to put it. And trying to run male software on a female OS causes the whole system to crash. The 'Fast Like a Girl' code is about learning to sync your lifestyle—your food, your workouts, and especially your fasts—to your body's natural rhythm. No fasting, or only very gentle fasting, in that week before your period.

Sophia: You know, the big picture that's emerging for me here is that our bodies, especially women's bodies, aren't simple machines. They're not cars where you just put in fuel and go. They're more like complex ecosystems, like a wild garden with its own seasons and rhythms. Laura: That's a beautiful way to put it. And for decades, we've been trying to apply a factory manual to that wild garden. We've been told to ignore the seasons, to suppress the rhythms, and just follow a rigid, mechanical set of rules. Sophia: And then we blame ourselves when the garden doesn't flourish. We think we used the wrong fertilizer or didn't water it enough, when really, we were trying to force roses to bloom in the middle of winter. Laura: Exactly. And Dr. Pelz's core message is to stop fighting the garden and start learning its seasons. It's about empowerment through biological literacy. And the most powerful first step isn't even a 24-hour fast. It’s just awareness. Sophia: What do you mean? Laura: Just start tracking your cycle. There are tons of apps for it. And don't just track your period; track your mood, your energy, your cravings. Start to notice the patterns. When do you feel powerful and ready to take on the world? When do you feel like you need to retreat and rest? Sophia: Just becoming an observer of your own ecosystem. Laura: Yes. That awareness is the real beginning. Once you see the rhythm, you can start to work with it. Maybe you schedule your biggest work projects during your 'power phase' and give yourself permission to have a cozy night in with some sweet potato fries during your 'nurture phase'. Sophia: That feels so much more compassionate and sustainable than the all-or-nothing approach of most diets. It’s not about restriction; it’s about attunement. Laura: Attunement. That's the word. And this is such a huge topic, we know it brings up a lot of questions and personal experiences. Sophia: Absolutely. We'd love to hear your stories with this. Have you ever felt like your body was fighting back against a diet? Have you experimented with fasting? Find us on our socials and share your journey. We really believe these conversations are where the most important insights happen. Laura: This is Aibrary, signing off.