Ep. 9: Why Your Fasting Is Not Working: The 3 “O”s — with Dr. Regina Druz, MD, MBA, FACC, FMCP-M, integrative cardiologist

It’s the first episode of 2025, and Dr. Regina Druz tackles what almost everyone is thinking about in January: weight loss — and specifically, why fasting so often fails. Inspired by a patient who was doing “everything right” (gluten-free, low-carb, daily workouts) yet gaining weight and watching her cholesterol climb, Dr. Druz lays out the three “overdues” — the 3 O’s — that quietly sabotage lifestyle efforts: over-fasting, over-restricting carbohydrates, and over-stressing through exercise without recovery. Drawing on real data from her patients’ digital biomarkers, she explains why, when it comes to fasting, less is often more — and previews the data-driven, “AI 2.0” approach Holistic Heart Centers is using to take the guesswork out of metabolic health.

Watch on YouTube: A video version of this episode is available on the Own Your Heart Health YouTube channel. Subscribe to be notified of new episodes.

Episode Chapters

[00:00] Introduction: The First Episode of 2025
[03:30] When Your Lifestyle Effort Backfires
[06:00] The First O: Over-Fasting
[10:30] Finding Your Window: Time-Restricted Eating
[13:30] Reading Your Body & the Lumen Data
[18:30] The Second O: Over-Restricting Carbs
[26:30] The Third O: Over-Stressing
[32:30] Digital Biomarkers & How We Found the 3 O’s
[34:30] AI 2.0 at Holistic Heart Centers
[37:00] Join the Group Program & Closing

Transcript

[00:00] Introduction: The First Episode of 2025

Dr. Regina Druz (00:00): Welcome to Own Your Heart Health. I’m Dr. Regina Druz, your holistic cardiologist. This week we’ll dive into common heart health concerns, uncovering root causes and unpacking scientific discoveries and controversies. The information provided does not constitute medical advice. Please contact your healthcare practitioner before making any changes that may impact your health.

Dr. Regina Druz (00:30): And just like that, we’re in 2025. Welcome, everyone, to the first episode of the year, and I’m going to tap into something almost everyone is thinking about right now: weight loss. The topic of this episode is why your fasting isn’t working — and what you can actually do about it. I was inspired to record this after reading a patient intake form. We solicit input from prospective patients to understand their challenges and goals and whether we can help. This patient — a very active woman in her sixties taking real ownership of her health — wrote that she’s already gluten-free, eating low-carb, and exercising every day, including yoga. And despite all of it, her cholesterol keeps rising and she recently gained 10 pounds.

Dr. Regina Druz (02:00): I reflected on it because I’ve seen this so often. Patients come in and say, “Doc, I’m already doing everything right — I fast 14, 16, 18 hours a day, I limit carbs, I work out — and I still can’t lose weight,” or they hit a plateau, or their cholesterol, glucose, or HbA1c won’t budge and is even heading the wrong way. This patient captured it perfectly: she’s doing all the things we’ve been told are right, doing them consistently and with real commitment, and yet her labs and her weight are moving in the opposite direction.

[03:30] When Your Lifestyle Effort Backfires

Dr. Regina Druz (03:30): If you’ve been in that boat — where your lifestyle effort didn’t improve your blood work, weight, or blood pressure — you have to ask what’s actually going on. What I’ve found over the past year, working with my team and many patients on metabolic health, is that when your fasting fails — or your entire lifestyle approach fails — there are usually three reasons, and they’re not what you’d think, because this is a situation where less is actually more.

Dr. Regina Druz (04:15): In this episode I’ll give you an insight into what I call the three O’s — three “overdues” that a lot of us adults are doing as we try to improve our longevity and vitality, prevent or come off medications, and take ownership of our health. These three overdues are producing the opposite of what we expect. We’ll discuss them first, and then I’ll show you how we approach this at Holistic Heart Centers — because in 2025 we have tools and resources that let us dial in exactly what we should be doing instead of guessing. Why guess when you can have a detailed, personalized approach? It’s not difficult; it just takes understanding, consistency, commitment, and the willingness to be coached.

[06:00] The First O: Over-Fasting

Dr. Regina Druz (06:00): So what are the three overdues that jeopardize people’s lifestyle efforts? We see them primarily in women, though men partake too. Two of the three relate to nutrition, and the third is more general, tied to exercise and recovery. The first O — the first overdue — is over-fasting. I routinely see patients who proudly say, “I fast 14 hours, I can go 16 hours on just water, I’m going to do a 24-hour water-only fast.” And I tell them: please don’t. We’ve observed — and it’s well established in the literature — that beyond a certain daily fasting threshold, your body goes into a state of stress.

Dr. Regina Druz (07:30): We’re creatures aligned with the circadian rhythm — day and night. We’re built to fast overnight, as primitive humans did, and then break the fast — breakfast. Our biology looks for the first energy input within a reasonable window, usually a couple of hours after waking. When we wake, cortisol spikes — that’s expected and helpful, mobilizing us for the day. But if you don’t eat for a prolonged period, that cortisol spike never comes down. I routinely see patients doing the three O’s whose cortisol curves are abnormal: they start high, stay high, maybe dip a little midday, then rise again at night. That sustained cortisol spike from over-fasting keeps you in fight-flight-or-freeze — a pro-inflammatory mode that impedes metabolic health and fat loss.

Dr. Regina Druz (09:30): Hi everyone, it’s Dr. Regina. I know there are contradictory opinions about nutrition for heart health and longevity — the discussion gets heated and confusing. Some push low-fat, low-cholesterol; others are fans of ketogenic diets; and there are many voices urging vegan or vegetarian eating. To cut through the clutter, my team and I created Holistic Heart University: on-demand courses, nutrition and lifestyle resources, and supplement guidance to make healthy choices for your heart easier to understand. I’m especially proud of our open office hours and the Q&A feature where you can put us in the hot seat. Head to the show notes for the link and use promo code OWNER20 for 20% off our annual subscription. I’ll see you in office hours.

[10:30] Finding Your Window: Time-Restricted Eating

Dr. Regina Druz (10:30): So how do we figure out how long someone should fast? We start with a modest fast — usually 12 hours, no more than 14 on any given day — and we advise all our patients to practice time-restricted eating. Time-restricted eating isn’t the same as fasting; they’re related but distinct. It means consuming all of your calories within a certain window, and that window needs to align with daytime and keep you from eating at night. If you live closer to the equator — say Florida or the Caribbean — even winter days are longer, so you have a wider window; in northern climates the window is shorter.

Dr. Regina Druz (12:00): For most people in the U.S. and Europe, that window falls roughly between 10 a.m. and 7 p.m. local time, and you can shift it an hour or two in either direction. Even where there’s strong seasonality, you can start conservatively and learn whether a given fasting interval works for you. So yes, you can fast 12 hours — but make sure those 12 hours are also time-restricted: the fasting interval happens overnight, and the eating window, when you replenish nutrients, happens during the day.

[13:30] Reading Your Body & the Lumen Data

Dr. Regina Druz (13:30): In our programs we use a specific protocol to determine the right fasting window for each person. But if you don’t have any gadgetry — and you know me, I’m a gadget girl, so a gadget always shows up — what do you do? Start with a conservative 12-hour interval, keep time-restricted brackets around your eating, and watch your body’s response. How do you know you’re over-fasting? You may feel listless or anxious, tired, notice an increased heart rate or elevated blood pressure, and feel persistently hungry. Those symptoms are your signal.

Dr. Regina Druz (14:30): In our programs we use a device that measures, from your breath, the macronutrients you’re burning — so we can tell whether someone is over-fasting, under-fasting, or in the sweet spot. It’s a daily measurement, and it’s not the same as continuous glucose monitoring; in our experience CGM didn’t connect the dots the way this device did. The device is called the Lumen. If you’re listening on audio, this is a great point to switch to YouTube — we’re about 14 minutes and 45 seconds in — because I share some preliminary data from our patient group.

Dr. Regina Druz (16:00): Here’s a high-level overview of what we learned from patients who’ve been very successful. We have a fairly equal number of men and women; many came to us overweight or obese, though some are at a healthy weight or even underweight. Using the Lumen, we could see who wakes up in fat burn — about 43% of our patients did. Their goals were common ones: roughly 39% wanted metabolic-health improvement, about 23% fitness or performance, and around 36% healthy weight loss. The progress of compliant patients has been astounding — and the key point is that their average daily fast was only 12 hours. That’s why not over-fasting is so impactful: over-fasting produces sustained stress and cortisol elevations that hold your body back from what it’s supposed to do.

[18:30] The Second O: Over-Restricting Carbs

Dr. Regina Druz (18:30): So over-fasting is the first O. The second is over-restricting — and it usually comes down to carbohydrates. Remember my patient vignette: “I’m already gluten-free, already low-carb.” Many patients over-restrict carbs. I know there are different schools of thought, and people will tell me how well they did on low-carb, ketogenic, or paleo diets — and vegan or vegetarian diets actually run higher in carbohydrates because they’re whole-food, plant-rich, which we know supports health, though not always metabolic health. But over-restricting carbs prevents you from maintaining good muscle mass and losing visceral fat, and it impairs your microbiome, because you need fiber and certain complex carbs to create the prebiotic and probiotic environment your gut needs. This is a huge issue, and women seem more often affected than men.

Dr. Regina Druz (20:00): How do we solve it? First, a nutritional assessment that calculates your actual macronutrient requirements, which we then adjust to your plan — and yes, the Lumen helps us titrate macronutrients precisely. It uses sophisticated AI to analyze your patterns and build a representation of you — what the tech-minded among us call a digital twin — of how you process macronutrients. It’s not set in stone at 30% fat, 30% protein, 40% carbs; depending on your activity, stress, exercise, and sleep — the factors that shape your metabolic flexibility — the amounts may need adjusting. Sometimes you need a carbohydrate “boost day.” Patients often say, “that’s too many carbs, I don’t eat that many,” and we say: just try it, because you’ll notice the difference. Could you do this without a device? It would be quite challenging — but with one, we have an extraordinary opportunity to help patients stop over-restricting.

Dr. Regina Druz (23:30): Over-fasting and over-restricting carbs are the top two reasons I see patients struggling — not losing weight, not improving cholesterol or blood pressure. We’ve even noticed accelerated aging in some patients following these protocols. As you heard in my previous episode with Ryan Smith of TruDiagnostic, we measure biological and organ age, and we’re seeing accelerated aging in people who over-fast and over-restrict carbs. That isn’t a new finding, though detecting it via biological age is fairly novel. If you’d like to learn to fast properly, we invite you to our group program, where we run something called the Fasting Circle to help patients dial it in without over-fasting or over-restricting.

Dr. Regina Druz (24:30): Some interesting data on chronic over-restriction comes from gerontology. In the Biosphere 2 experiment, participants spent time on low-calorie, hypocaloric diets — and the research showed they didn’t do well health-wise: they sustained muscle wasting and had increased chronic disease, including cancer. If you want more on this, watch for an upcoming episode on the fasting-mimicking diet, where we’ll discuss how fasting and fasting-mimicking — as interventional approaches — should be used.

Dr. Regina Druz (25:30): Hi everyone, it’s Dr. Regina. Many of my colleagues and I are seeing patients arrive with self-ordered blood tests. When this trend started, I thought it would help — who doesn’t want more access to their health data? But too often self-ordered labs lead to more confusion and frustration: patients come in with a pile of results and are no better off. That’s why we created HeartWell Toolkits — a curated collection of at-home blood and genetic markers focused on heart and brain health that gives you the data you need to make informed, actionable decisions. You can order them at the shop on holisticheartcenters.com — the link is in the show notes. Use code TESTING10 for 10% off and free shipping.

[26:30] The Third O: Over-Stressing

Dr. Regina Druz (26:30): The third O is over-stressing. Many patients say, “I’m going all out — I’ll fast 14 to 16 hours, drop my carbs, and work out every single day, lifting weights.” My vignette patient was lifting weights and doing yoga seven days a week. Now, I’m not saying you shouldn’t be active every day — you should do appropriate physical activity daily; the human body isn’t made to sit still. In our patient group, people were working out seven days a week, with some walking and some weights, and average daily steps didn’t hit 10,000 — though 10,000 is an arbitrary number we’ll revisit. The problem is that many people who work out don’t understand they also need time to recover.

Dr. Regina Druz (29:00): The body isn’t a machine. If you don’t recover, you don’t repair; and if you don’t repair, damage keeps accruing and flips your switch from metabolic health to metabolic rigidity. When you over-stress it, the body starts down the path of rigidity, and you can become insulin resistant. If you’re an athlete — or a practitioner working with high performers — you’ve seen overtraining syndrome. My first encounter was a young CrossFit enthusiast who looked to be in fantastic shape, in the top 10% of exercisers, yet whose labs looked like he was on the brink of several major diseases. That was the hard part: convincing him to change his workouts to allow recovery. Once he did, within about 60 days there was full recovery and restoration of metabolic health.

Dr. Regina Druz (31:30): Nowadays we don’t have to guess — you can monitor your exercise and recovery and understand your stress resilience. Whether your stress comes from work, family, or physical exertion, not allowing recovery will over-stress you and flip metabolic flexibility into rigidity. My perennial favorite tool here is the Oura Ring — you can see me wearing it. I like the recent additions that let me see my stress-resilience pattern and sample my stress level in real time, so I can adjust: take small breaks, or go for a walk instead of lifting if my body signals I’m not recovered.

[32:30] Digital Biomarkers & How We Found the 3 O’s

Dr. Regina Druz (32:30): You might think this is a lot of work — all these devices, the Lumen, the Oura Ring, and many more. But it adds up, because I’m a huge advocate and expert in digital biomarkers. Digital biomarkers are simply health signals captured from digital devices — a Bluetooth blood-pressure cuff, an Oura Ring, the Lumen, a body-composition scale, a continuous glucose monitor, your smartwatch. Whatever you use generates these signals, and when we sample them, we begin to uncover patterns. The three overdues I’ve described today are exactly the consequence of incorporating digital biomarkers in our programs — that’s what led us to discover that, across virtually every patient, three things jeopardize fasting and lifestyle effort: over-fasting, over-restricting carbs, and over-stressing. In some patients one matters more than the others, but these three are consistent.

[34:30] AI 2.0 at Holistic Heart Centers

Dr. Regina Druz (34:30): It’s 2025, and in 2024 we were captivated by generative AI — it captured our imagination and is rapidly entering the mainstream of business. But what we do at Holistic Heart Centers is what I call AI 2.0, because it isn’t generative — it’s not a large language model where you type a prompt and get advice. It’s more powerful than that. In 2025 we’re building our first framework that brings together all these signals — digital biomarkers, blood markers, genetic markers, patient-derived markers — into a system that can predict which interventions and patterns are most likely to get you to your health goals.

Dr. Regina Druz (35:45): That matters because health goals are so often jeopardized — weight loss, elevated cholesterol, high blood pressure, the progression of heart disease, arrhythmias, cardiomyopathies. If we can bring a more comprehensive picture forward, avoid over-fasting, over-restricting, and over-stressing, and use specific strategies to repair metabolic health and switch it out of the rigidity that is a hallmark of aging — which occurs in all of us in mid-to-later adulthood, just to varying degrees — we can put you in the right place to achieve metabolic flexibility. It’s an exciting time, because we can finally help patients understand, before they commit to a path, how likely that path is to help them.

[37:00] Join the Group Program & Closing

Dr. Regina Druz (37:00): If you’d like to join us, it’s not too late. We’re launching our first group program — a cardiometabolic, digitally enhanced program — and to appreciate the trust of this first cohort, anyone who enrolls before it launches in the next couple of weeks will receive a useful surprise gift to use during the program. There are only 10 spaces, and not many remain. If you’re interested, follow us on Facebook, Instagram, or YouTube and send us our group-program keyword to receive more information and claim your free gift with enrollment. Do it soon, so you’re not someone we have to turn away.

Dr. Regina Druz (38:30): I hope you share my excitement and will join us to take advantage of this opportunity in 2025: leveraging digital biomarkers and AI 2.0 to give patients a real way to own their health. The name of this podcast is Own Your Heart Health, and that’s exactly what I want you to do — own your heart health, own your health in general, and take incremental, smart steps on the road to transformation and longevity. Thank you for tuning in to Own Your Heart Health with Dr. Regina Druz. This podcast is powered by Holistic Heart Centers. If you enjoyed the show, please rate and review us on your favorite platform, and visit holisticheartcenters.com and subscribe to our YouTube channel. See you next week.

Frequently Asked Questions

What are the “3 O’s” that keep fasting from working?

Dr. Druz uses “the 3 O’s” — three “overdues” — to describe the most common reasons a disciplined lifestyle effort backfires. The first is over-fasting: pushing daily fasts well beyond about 12–14 hours, which can keep cortisol elevated, lock the body into a stress (“fight-or-flight”) state, and impede fat loss. The second is over-restricting carbohydrates, which can cost you muscle mass, make it harder to lose visceral fat, and starve the gut microbiome of the fiber it needs. The third is over-stressing through exercise without adequate recovery, which can tip the body from metabolic flexibility into metabolic rigidity and insulin resistance. The recurring theme is that when it comes to these behaviors, less is often more. This is educational content; work with your own clinician before changing your routine.

How long should I fast, and what is time-restricted eating?

In her programs, Dr. Druz typically starts patients with a modest 12-hour fast — no more than 14 hours on any given day — paired with time-restricted eating. Time-restricted eating is related to fasting but not identical: it means consuming all your calories within a defined daytime window (for many people in the U.S. and Europe, roughly 10 a.m. to 7 p.m., adjustable by an hour or two), so that the fasting interval falls overnight and aligns with your circadian rhythm. Signs you may be over-fasting include listlessness, anxiety, fatigue, elevated heart rate or blood pressure, and persistent hunger. Some programs use breath-based metabolic measurement (Dr. Druz uses a device called the Lumen) to identify each person’s “sweet spot,” but you can start conservatively on your own and watch how your body responds. Always personalize with a qualified clinician, especially if you have a medical condition.

Can cutting carbs too much actually be harmful?

According to this episode, yes — chronic over-restriction of carbohydrates can backfire. Dr. Druz explains that cutting carbs too aggressively can make it harder to preserve muscle mass and lose visceral fat, and can impair the gut microbiome, which depends on fiber and certain complex carbohydrates to maintain a healthy prebiotic and probiotic environment. She notes that the right amount of carbohydrate isn’t a fixed ratio — it depends on your activity, stress, exercise, and sleep — and that some people actually need a carbohydrate “boost day.” She also references gerontology research, including the Biosphere 2 experiment, where prolonged low-calorie eating was associated with muscle wasting and more chronic disease. The takeaway is that more restriction is not automatically better; the goal is the right amount for your physiology, ideally guided by assessment rather than guesswork.

What are digital biomarkers, and how do they guide a personalized plan?

Digital biomarkers are health signals captured from digital devices — a Bluetooth blood-pressure cuff, a wearable ring, a breath-based metabolic device, a body-composition scale, a continuous glucose monitor, or a smartwatch. Dr. Druz explains that sampling these signals over time reveals patterns that no single snapshot can: it was precisely this approach that surfaced the “3 O’s.” She describes building a personalized “digital twin” of how an individual processes macronutrients, and frames the broader effort as “AI 2.0” — not a generative chatbot, but a predictive framework that combines digital, blood, genetic, and patient-reported markers to estimate which interventions are most likely to help a given person reach their goals. The aim is to replace guesswork with a data-driven, personalized plan. As always, interpret your own data with a clinician, particularly if you have an existing condition.

Show Notes & Resources

Host: Dr. Regina Druz, MD, FACC

Dr. Regina Druz is a board-certified holistic cardiologist and the founder of Holistic Heart Centers. She blends conventional cardiology with integrative, root-cause medicine, with a focus on cardiometabolic health, personalized prevention, and cardiovascular longevity. A self-described “gadget girl” and expert in digital biomarkers, she runs data-driven cardiometabolic programs that combine wearable and breath-based measurements to personalize nutrition, fasting, exercise, and recovery. She is the host of Own Your Heart Health and the creator of Holistic Heart University and the HeartWell Toolkits.

Resources Mentioned in This Episode

Holistic Heart University — on-demand courses, the Heart Health & Wellness membership, and the group program’s Fasting Circle (use code OWNER20 for 20% off an annual subscription)
HeartWell Toolkits — at-home heart and brain health lab panels (use code TESTING10 for 10% off and free shipping)
Previous episode — biological age and DNA methylation testing with Ryan Smith of TruDiagnostic
Upcoming episode — the fasting-mimicking diet (interventional fasting approaches)
Lumen — breath-based metabolic measurement device used to find each patient’s fasting “sweet spot” and titrate macronutrients
Oura Ring — wearable for sleep, recovery, stress exposure, and resilience
Biosphere 2 — gerontology research on prolonged hypocaloric diets and their downsides (muscle wasting, chronic disease)

Holistic Heart Centers

holisticheartcenters.com
HeartWell.ai — AI-powered cardiovascular risk assessment
Address: 55 Bryant Avenue, Suite #6, Roslyn, NY 11576
Phone: 877-511-5166
YouTube: @reginadruzmd
Instagram: @dr.reginadruz
Podcast: Own Your Heart Health — available on Apple Podcasts, Spotify, and all major platforms

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