Bite Back with Abbey Sharp - The Cortisol Conspiracy: The Big Bad FAT GAIN Hormone or Wellness Culture Scapegoat?

Episode Date: November 4, 2025

Here’s a run down of what we discussed in today’s episode:IntroductionWhat is cortisol?The Body’s Traffic Light System: How Cortisol Keeps You MovingWhen Stress Gets StuckCortisol & Belly Fat: Myth or Truth?Dieting, Fasting, and Cortisol: What the Research Actually SaysThe Truth About Intermittent Fasting and Hormone TimingHow Cortisol Disrupts Hunger, Cravings, and SleepDoes Exercise Raise or Regulate Cortisol?Coffee, Sugar, and Stress HormonesGetting Your Cortisol Back on TrackReferences:Effects of physiological hypercortisolemia on the regulation of lipolysis in subcutaneous adipose tissueEstimation of body fat and lean tissue distribution by dual energy X-ray absorptiometry and abdominal body fat evaluation by computed tomography in Cushing's disease Disclaimer: The content in this episode is for educational and entertainment purposes only and is never a substitute for medical advice. If you’re struggling with with your mental or physical health, please work one on one with a health care provider.If you have heard yourself in our discussion today, and are looking for support, contact the free NEDIC helpline at 1-866-NEDIC-20 or go to eatingdisorderhope.com. Reach Your Weight & Health Goals - Without Dieting! Pre-Order The Hunger Crushing Combo Method, Abbey’s revolutionary additive approach to eating well to boost satiety, stabilize blood sugars, reduce the risk of disease, improve your relationship with food by providing the best nutrient bang for your caloric buck. With over 400 research citations, cheat sheets, evidence based actionable tips, meal plans and adaptable recipes, the Hunger Crushing Combo Method is the only nutrition bible you’ll ever need. Pre-Order today and submit your proof of purchase to get a FREE HCC Holiday Survival Guide here.Where to Purchase:AmazonB&N Amazon Kindle Apple Books Google PlayKobo Apple Books (Audio) Audible  More information and retailers here: abbeyskitchen.com/hunger-crushing-combo 🥤 Check out my 2-in-1 Plant Based Probiotic Protein Powder, neue theory at www.neuetheory.com or @neuetheory and use my promo code BITEBACK20 to get 20% off your order! Don’t forget to Please subscribe on Apple, Spotify or wherever you get your podcasts and leave us a review! It really helps us out. ✉️ SUBSCRIBE TO MY NEWSLETTERS ⤵️Neue Theory newsletterAbbey's Kitchen newsletter 🥞 FREE HUNGER CRUSHING COMBO™ E-BOOK! 💪🏼 FREE PROTEIN 101 E-BOOK! 📱 Follow me! Instagram: @abbeyskitchenTikTok: @abbeyskitchenYouTube: @AbbeysKitchen My blog, Abbey’s Kitchen www.abbeyskitchen.comMy book, The Mindful Glow Cookbook affiliate link: https://amzn.to/3NoHtvf If you liked this podcast, please like, follow, and leave a review with your thoughts and let me know who you want me to discuss next!

In fact, some studies actually find that higher cortisol levels while dieting is associated with greater weight loss outcomes. Welcome to another episode of Byteback with Abby Sharp, where I dismantle diet culture rules, call it the shellotins spinning the suit of science, and help you achieve food freedom for good. Today on Byteback, we are going to be diving into one of the most talked about and yet hugely misunderstood hormones, cortisol. Cortisol has recently been cemented into our layperson vernacular as the big bad stress hormone, blamed for everything from belly fat to cravings to burnout. But is it the key factor in explaining all that ails us or just the convenient scapegoat? Today we are breaking down what cortisol really does, whether or not it's truly the demon hormone that we've made it out to be, the role of calorie restriction, intermittent fasting, hit training, and coffee on cortisol levels, and what you can do to keep it balanced.

Before we get into it, I would love if you would give bite back a follow wherever you get your podcast and leave me a little review or comment. It really, really does make my day. Also, a quick reminder that my book, the hunger-crushing combo method is now available for pre-order in the links in our show notes. And pre-orders are super duper important to us authors. They play a huge role in the success of a book. And right now, you will get a free hunger-crushing combo holiday survival e-book if you prove your pre-order purchase. So check out all the links in the descriptions on how you can redeem. for that. Thank you guys so much for the support. All right, let's get into it.

All right, to set the stage, we should probably define what cortisol actually is. Cortisol is a hormone pumped out by your adrenal glands in response to physical or emotional stressors. And while that definitely kind of paints it in a bad light, it's actually essential to life. cortisol sets the rhythm for our day, naturally rising in the morning to wake us up out of our slumber and tapering off before bed to give us a chance to rest. Its main job is to mobilize energy by breaking down stored sugar, fat, and even protein to be used as fuel while also helping to stabilize blood pressure to get oxygen and nutrients around our body. Little bursts of cortisol in times of need also help temporarily sharpen our attention and memory and boost our immune system to fight off

stress or injury. Cortisol also plays a big role in metabolism by working alongside the hormone insulin to regulate blood sugar and energy balance. So when you eat a meal, especially one with carbohydrates, your blood sugars rise and insulin steps in to help move that sugar into the cells. Shortly after, cortisol levels also rise, which then ensures glucose is available to the brain and muscles, it stimulates enzymes that help to metabolize nutrients, and even works with the gut and liver to manage which fuel gets used and which gets stored.

You can kind of think of cortisol as the traffic controller of a traffic light system in our body. It coordinates the surge of nutrients when food has been consumed, and the mobilization and distribution of backup energy when food is scarce. In a traffic light system, a green light, a.k.a. a burst of cortisol tells everything to mobilize and move in a safe and calculated rhythm. And a red light, aka a dip in cortisol, tells us to slow down and rest. Without cortisol levels rising, we would all be stuck at a stand halt worse than a car on the Golden State Freeway on a Friday afternoon. So when we face a normal daily stressor like exercise or your alarm clock going off or a big presentation, cortisol tells the body, hey girl, let's do this. But if our traffic

light system is stuck on green 24-7, we would be stuck living in a state of absolute chaos, danger, and pile-up accidents. This is what happens with long-term stress. When cortisol stays elevated day after day from morning through night, whether from constant work pressure, lack of sleep, or even overtraining or under-eating, as we will soon discuss, the very systems that it's meant to protect start to break down. The natural rhythm becomes dysregulated, and we see devastating effects on mental and physical health. And of all the negative health outcomes of chronically high cortisol. The one that you've probably heard the most about is weight game. And not just any weight, but that quote unquote spare tire look from extra belly fat. So is this an urban myth or a

legit outcome of too many stressful nights in the office? Well, let's get into the science. As we've already mentioned, when our cortisol levels rise, we actually break down our stored energy sources. from carbs, fat, and protein. So believe it or not, cortisol can result in a net breakdown of fat across the body. Uh, wait a minute. So does that mean stress is like some kind of diet hack? Uh, not so fast. Cortisol has this cheeky little quirk where despite its role in breaking down total body tissue to be used as fuel, it actually halts or decreases the breakdown of belly fat, aka the visceral fat that surrounds our essential organs. So when we look at conditions like Cushing Syndrome that are characterized by excessive cortisol

production, we see significantly higher levels of belly fat and lower muscle mass, which is a body composition associated with impaired metabolism and chronic disease. We also can't forget about the relationship between cortisol and insulin. When we perceive a stressor and cortisol rises to mobilize stored sugars in the blood, insulin also pipes up to get that sugar into our muscle cells. But when insulin levels are also chronically high, it tells the body to store visceral fat. And that visceral fat doesn't just sit there and look pretty. It actively releases inflammatory molecules that can further disrupt insulin sensitivity, keeping us locked in a cycle of belly fat storage, insulin resistance, and metabolic dysfunction. As annoying as this mechanism

is, from an evolutionary perspective, it actually does make sense. In long periods of famine or danger, aka major stressors on the body, it would be protective to keep quick access energy stores close to vital organs around the gut. But in 2025, when we're more likely to be staring down, a mountain of bills and deadlines than like a sleuth of threatening bears, these mechanisms are, well, kind of a bust. So here's where things get controversial and confusing. Let's just say that you've noticed this pattern. You've had a super stressful season at work, and you start to notice that you're feeling a little weaker in the gym while your pants are fitting extra snug around the waste. You assume it's cortisol doing its dirty work and you want to reclaim a healthier body

composition. So you vow to cut back calories ASAP and hit up the hit boot camps every single day. You've got a plan and it's going to be extreme. But wait, the next time you open your TikTok, you get flooded with all these gorgeous Pilates girlies swearing that cardio, fasting, or even slashing calories is going to spike your cortisol and actually make the belly fat worse. Oh, what's a girl to do? Well, let's fact-check some of these assumptions together. Assumption number one, dieting raises cortisol and makes you gain belly fat. So here's the truth. That unqualified influencer is kind of right about something. Calorie restriction does boost cortisol, with research suggesting that the greater or longer the calorie deficits it, the higher the levels.

And this is particularly apparent when we look at people who are fasting for long periods of time, like over a few days, where we see the highest cortisol levels. And again, if we just go back to evolution for a minute, this makes total sense because we would need that cortisol to force our body to break down all of its stored energy sources when it's not getting enough from food. Now, considering we just made the connection that high cortisol can increase belly fat storage and that dieting can increase cortisol,

it would make sense that high cortisol is associated with impaired weight loss. However, research suggests that there is actually no association between cortisol levels and someone's ability to lose weight. In fact, some studies actually feel find that higher cortisol levels while dieting is associated with greater weight loss outcomes. And this isn't because cortisol is helping you lose weight. It's simply that a calorie deficit is associated with higher cortisol levels and weight loss. Basically, the calorie

deficit is just independently associated with both of these things. But what about the risk of belly fat storage while you're trying to lose weight elsewhere? Well, that is a potential concern. And to clarify, it's not so much that your diet is specifically going to make you gain belly fat, but it may mean that you hold onto that midsection fat longer while you lose weight elsewhere. Not ideal, obviously. But sadly, you can't spot reduced body fat, so you may end up losing your boobs before your belly, and that is just largely genetically based. So is there any better or worse way to quote quote diet when it comes to its impact on cortisol and therefore belly fat?

Well, maybe. Let's talk about intermittent fasting, aka restricting the time in which you eat. Now, to be clear, there's nothing magical about intermittent fasting for weight loss. The main reason why intermittent fasting, quote, quote, works, is that when we skip a meal, we just naturally tend to create a calorie deficit. And that can happen no matter what time your, quote,

eating window is. But different variations on fasting can have significantly different outcomes on our cortisol. Most people, when they say they're intermittent fasting, are skipping breakfast and then eating a later lunch and dinner. We call this late time restricted feeding. So when we fast all morning and then pack our calories in later on at night, we do tend to see an unnatural rise in cortisol levels in the evening. And again, this makes sense because eating anything will boost cortisol. Now, in contrast, when people practice what we call early time-restricted feeding, where they start eating in the morning and then basically skip dinner, even when we see that there is a calorie deficit at play, we're actually looking at a more stable, natural cortisol

pattern throughout the day, essentially a normal size bump in the morning and a tapering off at night. So why does the timing of your cortisol spike even matter? Well, cortisol participates in frequent crosstalk with other important hormones, telling our fullness hormone leptin to quiet down and our hunger hormone graylin to get louder. And again, this makes sense if it's mobilizing all of its energy sources to get things done. It's going to tell its buddies that you're going to need more fuel in the tank for the job, especially, ideally, fast fuel like refined carbs. So chronically high cortisol levels are associated with increased hunger and cravings specifically for what we call high reward foods, aka high sugar, high calorie

snack foods that are rapid and reliable energy sources. Now this is particularly problematic when we are skimping on sleep. If our cortisol levels are spiking before bed, which is counter to a normal cortisol pattern, we're not going to be able to wind our body down to get a good night's rest. And poor sleep is also associated with increased hunger hormones, making staying in a calorie deficit much more difficult and belly fat gain more likely. And back to what we said earlier, more belly fat means more insulin resistance, which just further entrenches you in aptite hormone mismanagement and weight gain. And this is a vicious feedback loop cycle that escalates the dysregulation and becomes really, really hard to reset. So what can we take from all these

complicated mechanisms? Well, cortisol itself doesn't directly impair weight. loss, even if it might make losing belly fat a little more challenging. But when there is a dysregulated cortisol pattern, its impact on sleep, aptite cravings, and food choices might interfere with your weight loss success. So if you are dieting or intermittent fasting, it's best to align your meals with your natural circadian rhythm to minimize the effect on cortisol, meaning more calories in the day and fewer later on at night. But let's move on to the other side of the energy balance equation with assumption number two, that heavy exercise raises your cortisol and again will make you gain belly fat.

Listen, I would love any scientific reason to not do cardio as that influencer that you follow might suggest. But sky-high cortisol making me gain belly fat is not going to be it. Like calorie restriction, exercise is a stressor on the body. If it wasn't, we wouldn't see any potential adaptations that help to make a stronger or fitter over time. And research has shown that intense exercise. sessions that last over an hour do tend to result in significant increases in cortisol levels. But as we discussed earlier, a transient boost in cortisol isn't actually a bad thing. It's literally just doing its job. So when you exercise, cortisol is just helping you mobilize

energy to fuel that workout. So having higher levels during or after a workout is not only normal, but it's also helpful. Research suggests that cortisol may actually improve exercise performance with studies showing that higher levels after a strength training session has a stronger association with muscle gain than both testosterone and growth hormone. Crazy, eh? What is even more reassuring about exercise is that while it is associated with a boost in cortisol during and after a workout when we need it,

It's linked to lower levels over the course of the day overall. Even when we study professional sprinters during their most intense training periods, we see that they have lower overall cortisol levels than their non-exercising counterparts. So in most circumstances, exercise, even more intense types of exercise, is good for cortisol levels. Now, the circumstance where it is not so good is when you're combining that exercise, with a restrictive diet. So for example, some women who end up losing their period because they restrict calories and or carbs and they engage in high levels of activity tend to have higher cortisol

levels and a 7% lower resting metabolic rate than what would be expected. Now, we're not sure if the high cortisol levels cause the menstrual dysfunction and lower the metabolism or whether the cortisol is just kind of along for the ride, but this is just another example of how diet restriction may negatively affect our cortisol levels. Now the last thing I want to cover quickly is all the chatter that we hear online about certain foods spiking or lowering cortisol. The big one I hear constantly from the wellness girlies online is about the alleged dangers of having coffee on an empty stomach. Here's the truth. Cortisol is already at its peak in the morning when we're consuming coffee. And while some studies suggest that caffeine may make this

bump a little higher, other research has found no increase in cortisol levels at all. And the likely reason for this discrepancy is that the effects seem to diminish with regular caffeine consumption. In other words, if you regularly drink coffee within an hour of waking on an empty stomach, your body just adapts to this habit, which significantly blunts the effects on cortisol. Another so-called cortisol spiking culprit is sugar. And the evidence here is really, really complicated and nuanced, because as we already established, eating anything, including sugar or otherwise, will stimulate some cortisol production.

But interestingly, having some food, including sugar on board when you're faced with a major stressor, actually seems to reduce the cortisol spike. because your brain knows it doesn't need cortisol to mobilize stored fuel. This dampening of cortisol reactivity partially explains why reaching for Ben and Jerry's helps quell all those uncomfy feelings. But when we're using sugar as our only tool in our emotional regulation toolbox, we might find ourselves stuck in a negative feedback loop where we feel stressed so we eat some sugar, our cortisol response dampens, we feel temporary relief, and then our brain learns that sugar

equals stressful leaf, and our habitual sugar intake as a coping mechanism just gets reinforced. In other words, short-term relief can become a long-term problem. So the big question becomes, how can you get your cortisol back into a healthy, natural rhythm? Well, I wanted to share some quick evidence. space tips. Number one, find coping mechanisms that don't involve food. Deep breathing, meditation, progressive muscle relaxation, and even short mindfulness breaks can lower our cortisol not just acutely, but can also improve overall cortisol patterns over time. Number two, focus on di-consistency, adequacy, and balance. Eating regular balanced meals with protein,

fiber-rich carbs and healthy fats, aka my hunger-crushing combo, helps to stabilize blood sugars and insulin, and reduce the need for a cortisol dump as an energy backup. Number three, move your body, but don't overtrain. You don't need to be afraid of hit training if that is what brings you joy. Just make sure that you're giving yourself adequate fuel and rest to prevent excess body stress. Number four, prioritize sleep. As we have discussed, a lot of the dangers of cortisol rhythm dysregulation are actually related to their intersection with poor sleep. So make a consistent relaxing bedtime routine with no social media, no blue light screens, and no stimulating substances.

Finally, build joy into your day. Believe it or not, but positive social experiences like laughing, singing along to music, on spending time with friends and loved ones help to release oxytocin, aka the bonding hormone, that actually counteracts a lot of cortisol's effects. So if you're feeling a little more stimulated and jittery, a Taylor-shrower sing-long might just do the trick.

And friends, that is all that I have for you guys today. If you're looking for some amazing tips on how to build those balanced meals to quell blood sugar, insulin, and cortisol spikes, and to help support a healthy weight and body composition without the risk of extreme diets. I would love if you would check out my brand new book, The Hunger Crushing Combo Method.

It is now on pre-sale and I would love your support because pre-sales really, really make a huge difference in the success of a book. And that success would really, really keep my stress and cortisol levels down. Thank you again, guys. But signing off with Science and Saz, I'm Abby Sharp. Thanks for listening.