202. How to Start Water Fasting Today: Benefits, Types and Who Should Avoid It

18 Sep 2025 · 11 min · 5 chapters

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In short

Science-based overview of fasting, especially water fasting—benefits, types, timing, who should avoid it, and warning signs.

Guest backgrounds

No guests are named in the provided transcript (the host mentions future live sessions with “gut experts” during a challenge).

Key claims

Fasting isn’t about “powering through pain”; biology and health status determine whether it helps or harms. Pregnancy/breastfeeding: avoid. PCOS: structured intermittent fasting may improve androgen levels, fertility, and menstrual regularity (cites a 2024 Current Nutrition Reports study). Chronic stress/insomnia/kidney disease: aggressive fasting may worsen stress. Menstrual cycle timing: follicular phase (days 1–14) is better due to higher insulin sensitivity; luteal phase (days 15–28) is harder due to insulin resistance and cravings. Types: time-restricted eating (e.g., 14-hour fast), 5-2, alternate-day, and water fasting (autophagy) with risks (electrolytes, nutrient deficiency, muscle loss).

Notable examples

stopping if persistent fatigue, sleep issues, prolonged anxiety/irritability, hair loss, or irregular cycles occur; women may do better with 12–14 hour windows.

Written by AI. May contain mistakes. Listen to the episode to check what was said.

Chapters

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Understanding Who Should Fast

0:38 to 2:32

Discover who can safely consider fasting and the associated health risks.

“The goal is to use fasting as a tool to improve your health, your energy, and your relationship with food.”

Menstrual Cycle and Fasting

2:32 to 4:00

Explore how a woman's menstrual cycle affects fasting success.

“Your biology and current health status determine whether fasting will help you or harm you, and ignoring these biological realities is why so many people struggle with fasting protocols.”

Types of Fasting Explained

4:00 to 6:43

Learn about different fasting methods and their unique benefits.

“What makes this approach so effective is that it aligns with your natural circadian rhythm.”

Water Fasting: Risks and Rewards

6:43 to 8:12

Understand the implications and benefits of water fasting.

“There are also some simple lab tests that can give you more objective information.”

Signs of Effective Fasting

8:12 to 11:03

Learn how to recognize if fasting is beneficial for your body.

“So aggressive fasting can signal your body that food is scarce, which can disrupt your reproductive hormone cycle.”
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Transcript

Automatic transcript. May contain errors.

0:00Every major religion prescribes it. Hunter-gatherers lived it.

0:03Gary Brecka:Even your pets do it naturally. So why are most modern humans the only species that's forgotten how to fast? And what's it costing our health? Today, we're going to cut through all the noise around fasting and give you the science-based framework you need to determine if fasting is right for your body, your goals, and your current health status. It's so important to understand that fasting isn't about powering through pain. It's supposed to be a way to improve health outcomes, not make them worse. Your biology and current health status determine whether fasting will help you or harm you. And ignoring these biological realities is why so many people struggle with fasting protocols.

0:38The goal is to use fasting as a tool to improve your health, your energy, and your relationship with food. Now let's break down the different types of fasting so you can choose the approach that matches your goals and your lifestyle.

1:04every major religion prescribes it hunter gatherers lived it even your pets do it naturally so why

1:11Gary Brecka:are most modern humans the only species that's forgotten how to fast and what's it costing our health today we're going to cut through all the noise around fasting and give you the science-based framework you need to determine if fasting is right for your body your goals and your current health status. Let's start by talking about who should and who shouldn't consider fasting. A lot of fasting content ignores the fact that certain health concerns and life circumstances do make fasting a bit dangerous. If you're pregnant or breastfeeding, fasting is off the table completely. Your body needs consistent nutrition during these critical periods.

1:46Gary Brecka:However, if you have PCOS, research indicates that intermittent fasting may actually improve your androgen levels and help regulate your menstrual cycles. A 2024 study published in current nutrition reports showed that significant improvements were found in fertility and menstrual regularity amongst women with PCOS who followed structured intermittent fasting protocols. If you're dealing with chronic stress, insomnia, or adrenal issues like chronic kidney disease, aggressive fasting can actually make these problems worse by adding additional stress to your system. In these cases, focusing on sleep quality and stress management should come before experimenting with fasting.

2:23Gary Brecka:It's so important to understand that fasting isn't about powering through pain. It's supposed to be a way to improve health outcomes, not make them worse. Your biology and current health status determine whether fasting will help you or harm you, and ignoring these biological realities is why so many people struggle with fasting protocols. For women, even the timing of your menstrual cycle can make the difference between success and struggle during a fast. New research indicates that the action of insulin is influenced by cycle timing. So during your follicular phase through ovulation, which is roughly days one through day 14 of your cycle, your insulin sensitivity is naturally higher.

3:01Gary Brecka:This is considered the best window for fasting. Your body is primed to use fat for fuel more efficiently during this time. But during your luteal phase, days 15 through 28, everything changes. Your body becomes more insulin resistant. You experience stronger cravings and stress hormones are naturally elevated. Fasting during this phase feels much harder because your biology is literally working against you. Now let's break down the different types of fasting so you can choose the approach that matches your goals and your lifestyle. Intermittent fasting is actually an umbrella term that describes cycling between periods of eating and fasting.

3:36Gary Brecka:Under this umbrella, there are several specific approaches, each with different benefits and challenges. Time-restricted eating is the most beginner-friendly approach. This involves eating all your meals within a specific window each day and fasting for the remaining hours. A popular version is the 14-hour fast, where you might eat between 8 a.m. and 6 p.m., then fast from 6 p.m. until 8 a.m. the next morning. What makes this approach so effective is that it aligns with your natural circadian rhythm. Your body is naturally more insulin-sensitive in the morning and early afternoon. That means that's your ideal time to eat.

4:11Gary Brecka:The overnight fasting period allows your digestive system to rest and gives your body time to shift into fat burning mode. Time-restricted eating can improve insulin sensitivity, sleep quality, and promote weight stability all without counting calories. Most people find this sustainable because you're sleeping through most of the fasting period. The 5-2 method takes a different approach. In this fasting protocol, you eat normally five days per week and then significantly reduce your calorie intake, usually to about 500 to 600 calories on two non-consecutive days. This method appeals to people who prefer having more flexibility in their daily eating schedule while still getting metabolic benefits from periodic calorie restriction.

4:52Gary Brecka:Alternate day fasting involves eating every other day. On fasting days, you either consume no calories or limit yourself to about 25 % of your normal caloric intake. On eating days, you consume your normal amount of food. This approach has shown impressive results in research for fat loss and improving metabolic markers, but it's not the most supportive of an active social lifestyle and might not be sustainable long-term for a lot of people. Now let's talk about water fasting, which involves complete absence from all calories consuming only water. This is the most intensive form of fasting and shouldn't be taken lightly.

5:28Water fasting can trigger deeper metabolic changes than other forms of fasting. It activates autophagy, which is your body's cellular cleanup process, where damaged proteins and organelles get recycled. It's like finding all the bad trash around the house and taking it all out at once.

5:44Gary Brecka:This protects your cells from damage by misfolded proteins or other waste products that can produce added stress. But it's incredibly important to know that water fasting also carries significant risks. Extended periods without food can lead to nutrient deficiencies, dangerous electrolyte imbalances, and muscle loss. Some people experience fatigue, dizziness, irritability, and difficulty concentrating. In extreme cases, water fasting can cause dangerous drops in blood pressure and blood sugar. With any fasting approach, matching the method to your current health status, lifestyle and goals matters more than following the most extreme protocol.

6:18Gary Brecka:There's no prize for doing the most intensive version of fasting. The best approach is the one you can maintain consistently while feeling strong and healthy. Rather than guessing or trying random approaches, there are signs and symptoms that tell you whether fasting is likely to help you. If you're dealing with metabolic issues like diabetes, obesity, thyroid disorders, fasting can be incredibly beneficial. When you fast, you give your body a break from constant food processing. This can help reset your hunger and fullness signals, improve how well your body uses insulin, and train your metabolism to become more adaptable, meaning it becomes better at switching between using glucose and fat for energy.

6:55Gary Brecka:There are also some simple lab tests that can give you more objective information. Basic markers like fasting blood sugar, triglycerides, and blood pressure can all indicate whether your metabolism is functioning well. You don't need to understand complex calculations. Your doctor can tell you if these numbers suggest you might benefit from intermittent fasting. The goal is to use fasting to help improve your metabolic markers, not as a solution to problems that might be better addressed through other approaches like improving sleep, managing stress, or adjusting what types of foods you're eating.

7:25Gary Brecka:One of the biggest mistakes people make is jumping into aggressive fasting protocols without allowing their body to adapt gradually. Your metabolism needs time to become efficient at switching between using glucose and fat for fuel. This process is called metabolic flexibility, and building it takes time. Pay attention to warning signs that indicate you should stop or modify your approach. If you're noticing persistent fatigue that doesn't improve after the first week of adaptation, difficulty sleeping, increased anxiety or irritability that lasts beyond just the initial adjustment period, intermittent fasting may not be for you.

8:00Gary Brecka:Other signs you might want to look out for are hair loss and irregular menstrual cycles in women. For women specifically, fasting requires extra consideration because of the more complex hormonal system. During your reproductive years, your body prioritizes having enough energy reserves to support potential pregnancy, even if pregnancy isn't your goal. So aggressive fasting can signal your body that food is scarce, which can disrupt your reproductive hormone cycle. This is why so many women do better with shorter fasting windows, 12 to 14 hours rather than 16 to 18 hours. What matters most is paying attention to how your body responds rather than forcing yourself to follow a protocol that doesn't match your biology.

8:41Remember, the goal of fasting isn't to prove how tough you are or to follow the most extreme protocol possible. The goal is to use fasting as a tool to improve your health, your energy, and your relationship with food. This means being willing to modify your approach based on how your body responds and recognizing what works for someone else might not work for you. If you found today's episode interesting and you're curious about completing a water fast, I invite you to join me October 15th, 16th, and 17th for the Ultimate Human Water Fasting Challenge. Over these three days, you'll be guided safely through the proper steps to prepare for and complete your fast.

9:17Along the way, you'll also have live sessions where I'll sit down with gut experts to discuss the benefits of fasting while you're experiencing the fast in real time. You can sign up using the link right here. It's completely free. If you wanna go further, join my VIP community for this challenge. As a VIP, you'll get an extra hour live with our guest experts to ask your own questions, the chance to be spotlighted and brought up in real time to ask me anything. And if you miss anything, you'll have full access to our replay library where every session lives for you to revisit anytime you want.

9:50Plus, once the challenge ends, you'll stay connected inside my VIP community, which includes monthly live Q &As with me, the full 10-month becoming the ultimate human course, and so much more. As we wrap up today's deep dive into fasting, I wanna leave you with the most important takeaway. Fasting is a tool, not a cure-all, and definitely not a test of willpower. The research is clear that when done appropriately, for the right person at the right time, fasting can provide significant benefits for metabolic health. But the words when done appropriately make all the difference. Your body will tell you if fasting is working, you just need to know how to listen.

10:27Successful fasting should leave you feeling energetic during your fasting periods, not exhausted. And finally, remember that fasting is just one tool in your health toolkit. It's not more important than eating nutritious foods, getting quality sleep, or managing stress and staying physically active. the most powerful approach to health is always the comprehensive one that addresses all aspects of your lifestyle. Your body has an incredible capacity for healing when you provide it with the right conditions. Sometimes that includes periods of fasting and sometimes it doesn't. The wisdom is in knowing the difference and being willing to adjust your approach based on what your body actually needs rather than what's trending on social media.

From the publisher

Join my FREE 3-Day Water Fast Challenge - October 15th. It's the exact protocol I use with pro athletes and Fortune 500 CEOs to flush inflammation, kickstart autophagy. Sign up here!  ⁠http://bit.ly/4nTILPt

Every major religion prescribes it, hunter gatherers lived it, even your pets do it naturally…so why are modern humans the only species that's forgotten how to fast? After 22 years of analyzing mortality data in the insurance industry, I've discovered the answer lies in understanding your unique biology and metabolic flexibility, not forcing your body into extreme protocols that work against its natural design. In this episode, I'm sharing the science-based framework I use to help people determine if fasting aligns with their current health status, goals, and hormonal patterns.

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Timestamps

00:00 Intro of Show

01:29 Who Should (or Should Not) Consider Fasting?

01:53 Fasting Timing during Women’s Menstrual Cycle

03:25 Different Types of Fasting

06:30 Water Fasting: How to Do It Safely

07:05 Simple Lab Tests to Determine Which Fasting Protocol Could Work for You

08:38 The Goal of Fasting

09:06 Join the Ultimate Human Water Fasting Challenge

Disclaimer: This podcast is for informational purposes only and does not provide medical advice. It is not intended for diagnosing or treating any health condition. Always consult a licensed healthcare professional before making health or wellness decisions.

Gary Brecka is the owner of Ultimate Human, LLC which operates The Ultimate Human podcast and promotes certain third-party products used by Gary Brecka in his personal health and wellness protocols and daily life and for which Ultimate Human LLC and / or Gary Brecka directly or indirectly holds an economic interest or receives compensation.  Accordingly, statements made by Gary Brecka and others (including on The Ultimate Human podcast) may be considered promotional in nature.
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202. How to Start Water Fasting Today: Benefits, Types and Who Should Avoid ItThe Ultimate Human with Gary Brecka · 11 min
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