The Power of Fasting

Revolutionize Your Health Through the Ancient Wisdom & Modern Science of Fasting

Dr. Aaron Hartman

December 26, 2023

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    Twenty years ago, fasting was almost entirely ignored by the medical community. If you heard about fasting, it was likely only in the context of a religious community. These days, you’ve probably had fasting recommended to you from a half dozen sources. I’ve personally recommended fasting while addressing anti-aging, inflammation, mood disorders, and a host of other topics.

    But if you’re new to fasting, it can be overwhelming and intimidating. In this article, I will explore the multifaceted nature of fasting—the science behind it, its benefits, and its pitfalls. I will share practical guidelines to implement fasting safely and minimize the discomfort typically associated with it.

    Introduction: Fasting (Old & New)

    Fasting is not a new concept; it’s a practice rooted in ancient traditions and was common in many cultures for most of our history. Only in more recent times (100–150 years) have we moved away from fasting as a regular part of our personal, religious, and societal practices.

    In the past few decades, however, fasting has increasingly been the subject of clinical research. Researchers like Dr. Valter Longo and Dr. Jeff Volek have been pivotal in bringing fasting into the spotlight of modern science.

    And with good reason…

    woman outdoor sweating

    The Many Benefits of Fasting

    The emerging research over the last few years has illuminated the profound impact fasting can have on our health. It’s anti-inflammatory, anti-cancer, anti-aging, and can significantly improve brain and gut function.

    Conditions like metabolic syndrome, PCOS, fatty liver disease, and insulin resistance are all influenced by our eating patterns, and fasting has shown promising results in mitigating and even reversing some of these issues.

    Kid taking out the trash

    Why is fasting so powerful?

    When you fast, your body has the opportunity to do some cleanup—your cells take out the trash! Cell trash and waste products accumulate every day in your metabolism. If we eat from sunrise to sunset, we are impairing our cells’ ability to detoxify. Fasting helps to accelerate the removal process.

    Research is showing that, in mouse models, a mouse’s life expectancy can be extended by 30% simply by fasting. CT scans of mice with cancer have shown that the size of tumors is reduced by 30–40%. Research in cancer and chemotherapy has shown that fasting improves the cells’ response to chemotherapy and also has a protective effect on normal, non-cancer cells.

    If fasting is so awesome, why don’t we talk more about it? Why aren’t we all fasting?

    Addressing the Challenges & Pitfalls

    While the benefits of fasting are substantial, it’s not without its challenges. Common side effects include:

    • Low sugar episodes
    • Dizziness
    • Lightheadedness
    • Irritability
    • Hunger pains
    • Strong cravings for carbohydrate

    While seemingly “normal,” these side effects are signals of metabolic dysfunction.

    A healthy metabolism will burn through the calories of a recent meal within 2–4 hours. After about eight hours, you should start using the energy stored in your muscles in the form of glycogen. After about 12 hours, you would then begin tapping into your fat stores to remove fat and use that for energy.

    What this means is if you only fast for about 8–10 hours a day, which is common for Americans, you never tap into fat stores, and you won’t lose weight. To lose weight, you need to refrain from eating for at least 12 hours. In other words, you need to fast. If you have a lot of the symptoms above, it’s a signal that your body’s metabolism can’t switch from sugar to glycogen to fat. Your metabolism is inflexible.

    Avoiding the Pitfalls

    At the risk of sounding obvious, my first line of advice is to start small and gradually increase the duration of your fasts, to allow your metabolism to transition. In addition, you can mitigate discomfort with the following strategies:

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    1. Drink Lots of Water

      The first key is to stay well-hydrated. Drinking clean, purified water helps to suppress your appetite and flush out cell debris and metabolites. I recommend drinking sparkling mineral water like San Pellegrino, which has a lot of trace minerals and is also slightly alkaline. This will support your body in detoxifying while also maintaining your electrolytes.

    2. Bolster Trace Minerals

      One of the common sources of these fasting symptoms is nutrient deficiencies of B vitamins, magnesium, or potassium. Since 60% of Americans are magnesium-deficient, 40–60% of us are potassium deficient, and 40–80% of us have some kind of B vitamin deficiency, the metabolism-revving effects of fasting can cause unpleasant symptoms. Addressing these deficiencies before your fast (through an improved diet) and during your fast (through supplements) can improve your experience.

      Recommended Supplement: Concentrace Trace Minerals

    3. Address Your Gut Health

      Ever heard of being “hangry?” While commonly blamed on low blood sugar, “hangry” is more accurately a mood instability induced by the bacteria in your gut producing pseudo-neurotransmitters (chemicals acting like neurotransmitters) that can drive hunger. Improving your gut health is another way to improve your ability to achieve an easier fast.

    Different Methods of Fasting

    Throughout my exploration of fasting, I’ve encountered several methods, each with its own benefits and considerations:

    Water Fasting

    This involves abstaining from all food, and only consuming water or other non-caloric liquids like tea or coffee (without cream or sugar).

    When you hear about the strong research for fasting, it typically refers to strict water fasting. The most powerful data is for strict fasts between 3–5 days. It’s a more intense form of fasting that can be stressful and typically requires additional accommodations for rest. The reality is that for most parents with children at home, most professionals, and most Americans in general, this is incredibly difficult to do.

    Man checking the time at his watch before eating

    Interval Fasting

    Also known as time-restricted eating or intermittent fasting, this method involves fasting for 12–16 hours a day and limiting your eating window to 8–12 hours.

    As noted above, it takes about 12 hours of fasting to burn through all of your body’s stores of sugar, glycogen, and carbohydrates and to switch over to burning fat and making ketone bodies. While this ramps up at around 16 hours and hits its peak at about day 2–3 of fasting, there is definitely an increase in fat burning and ketone production during interval fasting. If, while doing interval fasting, you also cut back on carbohydrates (especially processed ones), and increase fat and protein consumption, you can increase ketone production even more.

    Depending on who you read, recommendations for interval fasting windows vary. The benefits start at about 12 hours and increase as you work toward 16–18 hours. If you’re new to interval fasting, start at the lower level and build your strength and tolerance gradually.

    Fasting Mimicking Diet (FMD)

    Developed by Dr. Valter Longo, the FMD is a five-day plan that mimics the effects of fasting while allowing you to consume a reduced-calorie diet. The FMD was designed to be used for only 5 days at a time followed by a balanced, healthy diet which is resumed for at least 25 days in between each FMD cycle.

    The FMD does not generally induce full-blown ketosis or a full fasting state, but it does promote healthy changes including a reset of the gut bacteria as well as some of the similar signaling patterns seen in a full five-day water fast. Since the FMD allows a person to eat during the “fast,” it can be more accessible than strict, water fasting.

    The FMD has become popular with elite athletes in order to slim down and improve performance, as well as with executives who want improved cognitive function. Dr. Longo’s research demonstrates that 3 cycles of the FMD provides a significant metabolic reset. Dr. Longo’s work in using the FMD has achieved impressive results involving weight management, diabetes, cardiovascular disease, Alzheimer’s, autoimmune disease, and more.

    One of our health coaches, Jennie O‘Neil, has completed several cycles of the FMD and has written about her own experience with practical guidelines for implementing the FMD. If you’re interested in the FMD, I encourage you to read Jennie’s article, “DIY Fasting Mimicking Diet for Powerful Results.

    Final Thoughts

    As we’ve explored, fasting is more than just a health trend; it’s a practice with a long history and substantial scientific backing. Whether you’re considering water fasting, interval fasting, or the FMD, it’s important to approach it with knowledge, preparation, and professional guidance.

    Fasting is a personal journey, and what works for one person may not work for another. As always, your health and safety should be the priority in any health-related endeavor.

    As we continue to uncover more about the benefits and mechanisms of fasting, I encourage you to stay informed, consult with healthcare professionals, and consider how this ancient practice can fit into your modern lifestyle for improved health and well-being.


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