Fasting can seem intimidating. At least, it was for me.

In the past, I had "fasted" during Lent as part of my faith journey. However, it wasn't what most people would consider a true fast. Rather than abstaining from all food for 24 hours or longer, I would eat two small meals, avoid snacking, sugar, and sweets, and spend intentional time throughout the day in prayer.

While that experience brought meaningful spiritual and health benefits, it wasn't the same as a complete fast.

What I've since learned is that fasting offers powerful benefits both physiologically and spiritually. There are many different approaches, ranging from intermittent fasting to 24-hour, 36-hour, and even longer fasts. Each method can support health in unique ways.

Today, I want to provide the full picture of fasting—what actually happens in your body when you fast, why it can be such a powerful tool for health and healing, and how to begin in a way that is practical, progressive, and sustainable for real life.

Whether you're interested in fasting for metabolic health, inflammation, weight loss, spiritual growth, or simply giving your body a chance to reset, understanding the science behind it can help you approach fasting with confidence rather than fear.

Fasting is not starvation. It is not about deprivation, punishment, or white-knuckling through hunger with sheer willpower. And it does not require skipping meals indefinitely or eating nothing for days on end.

Fasting is simply the deliberate practice of extending the period between your last meal and your first meal of the following day — creating a window of time in which your body is not processing and absorbing food and can therefore turn its full attention toward the extraordinary biological work it can only do in the fasted state.

Your body already fasts every night while you sleep. Intermittent fasting simply extends that window intentionally — and in doing so, unlocks a cascade of biological processes that have profound implications for your health.

This is the part that changes how people think about fasting — because most people have no idea how much their biology shifts when food is withheld for an extended period.

Insulin drops — and fat burning begins.
Every time you eat — particularly carbohydrates and protein — your pancreas releases insulin to manage the glucose entering the bloodstream. While insulin is elevated the body is in storage mode — it is depositing glucose into cells, converting excess to fat, and actively suppressing the fat-burning pathways. Fat cells essentially cannot release their stored energy when insulin is present.

When you fast and insulin drops — typically beginning around the eight to twelve hour mark depending on what and when you last ate — the metabolic environment shifts fundamentally. The body transitions from glucose burning to fat burning, mobilizing stored fat for energy in a process called lipolysis. This is why fasting is one of the most effective metabolic interventions available — not because it reduces calories in a simplistic sense, but because it fundamentally changes which fuel source the body is drawing on.

Glycogen is depleted — ketone production begins.
The liver stores glucose as glycogen — a reserve tank that feeds the brain and body during the gaps between meals. During a fast this glycogen reserve is gradually depleted — typically within twelve to sixteen hours depending on activity level and metabolic state. Once liver glycogen is depleted the liver begins producing ketone bodies from fatty acids — an alternative fuel source that the brain, heart, and muscles can use in place of glucose.

Ketones are not just a backup fuel. They are a signaling molecule with documented neuroprotective, anti-inflammatory, and metabolic benefits. They reduce oxidative stress, support mitochondrial function, reduce neuroinflammation, and improve cognitive clarity in ways that glucose metabolism alone does not produce. The mental clarity many people describe during fasting — the sharpness and focus that appears somewhere in the sixteen to twenty-four hour window — is, in large part, the brain running on ketones.

Autophagy activates — cellular cleanup begins.
Autophagy — from the Greek words meaning self-eating — is the process by which cells identify, disassemble, and recycle damaged proteins, dysfunctional organelles, and accumulated cellular debris. It is the body's most sophisticated internal cleanup and quality control system, and it is activated most powerfully by fasting.

The 2016 Nobel Prize in Physiology or Medicine was awarded to Yoshinori Ohsumi for his research into autophagy — research that demonstrated how fasting triggers this cellular cleanup process and its implications for longevity, disease prevention, and cellular health. When you fast you are not just burning fat. You are triggering one of the most powerful anti-aging, anti-inflammatory, and disease-preventive biological processes available to human biology.

Autophagy becomes meaningfully active around the sixteen hour mark and intensifies with longer fasting windows — which is one of the strongest biological arguments for extending the fasting window progressively over time.

Growth hormone surges.
As we covered in the growth hormone newsletter — the relationship between fasting and growth hormone is one of the most compelling arguments for incorporating regular fasting into adult life. Growth hormone levels have been documented to increase dramatically during fasting — as the body shifts into repair and preservation mode. Growth hormone drives tissue repair, fat metabolism, lean muscle preservation, and cellular regeneration. Fasting creates one of the most powerful natural growth hormone stimulation environments available without pharmaceutical intervention.

The gut gets its recovery window.
The gut lining — the enterocytes and tight junction proteins that maintain the barrier between your intestinal contents and your bloodstream — undergoes significant repair and regeneration during fasting windows. The migrating motor complex — a wave of muscular contractions that sweeps the small intestine clean between meals — only activates during the fasted state. It is essentially a self-cleaning cycle for the gut that requires a minimum of ninety minutes of fasting to complete a full sweep and cannot operate when food is constantly present. Frequent eating suppresses this cleaning cycle entirely. Fasting restores it.

Inflammation decreases.
Multiple mechanisms of fasting converge on a single outcome — reduced systemic inflammation. Lower insulin reduces the pro-inflammatory signaling associated with insulin resistance. Autophagy clears the damaged proteins and dysfunctional mitochondria that drive oxidative stress and cellular inflammation. Ketone production directly inhibits the NLRP3 inflammasome — one of the primary drivers of chronic inflammatory disease. And the gut repair that fasting supports reduces the intestinal permeability that allows bacterial endotoxins into systemic circulation — one of the most significant drivers of chronic low-grade inflammation in the modern population.

Intermittent fasting is a pattern of eating — a framework that defines when you eat rather than prescribing exactly what you eat.

The most common and most well-studied intermittent fasting protocols are structured around a simple ratio of fasting hours to eating hours.

14:10 — 14 hours of fasting with a 10-hour eating window. The gentlest starting point. Most people achieve this simply by stopping eating after 7pm and not eating again until 9am. The vast majority of the fast happens during sleep. This is an accessible, low-disruption entry point for anyone who has never fasted before.

16:8 — 16 hours of fasting with an 8-hour eating window. The most widely studied and most widely practiced intermittent fasting protocol. Most commonly structured as eating between 11am and 7pm or noon and 8pm. At 16 hours the metabolic benefits of fasting — fat burning, early autophagy activation, insulin reduction — are meaningfully engaged. This is where most people find a sustainable long-term rhythm.

18:6 — 18 hours of fasting with a 6-hour eating window. A more advanced protocol that deepens the metabolic and autophagic benefits. Most commonly structured as eating between noon and 6pm. This protocol requires some adaptation but becomes surprisingly manageable once the body has adjusted to fat burning as a primary fuel source.

24-hour fast — one complete day of fasting, typically done once or twice per month rather than daily. The most powerful single fasting protocol for autophagy, growth hormone stimulation, gut repair, and metabolic reset. Not a starting point — but a meaningful destination for anyone who has built progressively through the shorter windows.

The key principle across all of these protocols is the same: the fasting window is when the biological magic happens, and extending it progressively over time deepens the benefits.

This is one of the most common questions — and the answer matters both for compliance and for whether the fast's biological benefits are maintained.

Yes — Water. Still or sparkling. Add a pinch of quality mineral salt like Baja Gold or Redmond Real Salt to replace electrolytes and support hydration at the cellular level. This is especially important for fasts longer than sixteen hours.

Yes — Black coffee. Plain, no milk, no sweetener, no creamers. Black coffee does not significantly raise insulin and does not meaningfully disrupt the fasted metabolic state. It also suppresses appetite, supports fat oxidation, and for many people makes the extended fast significantly more comfortable.

Yes — Plain herbal tea and plain black or green tea. The L-theanine in green tea provides calming focus that pairs beautifully with the mental clarity of the fasted state. Pique has high-quality teas (third-party tested), and ones that are specific for fasting.

Yes — Warm organic bone broth. During fasts of eighteen hours or more — particularly the 24-hour fast — a cup of warm organic bone broth is a great way to break a fast 30 minutes prior to your next meal. It provides glycine, glutamine, and minerals that support gut lining integrity and adrenal function without meaningfully disrupting the metabolic state of the fast.

No — anything containing calories, sugar, milk, cream, or sweeteners — including artificial ones. Even small amounts of these inputs raise insulin and interrupt the metabolic shift that is the foundation of fasting's benefits.

1. Start at 14:10 and stay there for two weeks.
Give your body time to adapt to the extended fasting window, to shift toward fat burning, and to establish the habit before pushing further. Two weeks at 14:10 creates the foundation that makes 16:8 feel natural rather than forced.

2. Adjust your eating window gradually.
If you are currently eating from 7am to 9pm — a fourteen-hour eating window — you do not need to immediately compress to noon to 6pm. Move the start of your eating window back by thirty minutes every few days. Gradual progression is the most sustainable approach and produces the same end result with less discomfort along the way.

3. Stay genuinely hydrated throughout the fasting window.
Most hunger during fasting is actually thirst or electrolyte depletion presenting as hunger. A large glass of water with a pinch of mineral salt at the first sign of hunger resolves it in most cases within five to ten minutes. Drink a minimum of sixty-four ounces of water daily during fasting protocols — more during longer fasts or in hot weather.

4. Break your fast with protein and fat first — not carbohydrates.
The first meal after a fast sets the metabolic tone for the eating window that follows. Breaking your fast with protein and healthy fat — eggs, avocado, grass-fed beef, wild-caught fish — produces a gentle, sustained insulin response and extends the fat-burning state into the eating window. Breaking your fast with refined carbohydrates or sugar produces a rapid insulin spike that immediately terminates the metabolic benefits of the fast.

5. Eat nourishing, whole food during your eating window.
Intermittent fasting is not a license to eat poorly during the eating window. The biological work that happens during the fast is supported — or undermined — by the quality of what you eat when you break it. Grass-fed protein, quality fats, abundant vegetables, fermented foods, and mineral-rich salt during the eating window compounds the benefits of the fast. Ultra-processed food, seed oils, and added sugar during the eating window undermines them.

6. Expect the first week to feel challenging — and trust the adaptation.
The first three to five days of any new fasting protocol typically involve some degree of hunger, fatigue, mild headache, or irritability — particularly in people whose bodies have been running primarily on glucose and have not practiced fat burning as a fuel source. This is the adaptation phase and is temporary. Most people report that by day five to seven the hunger becomes dramatically easier to manage, energy stabilizes, and the mental clarity that fasting produces begins to emerge. Staying focused on your health goals makes it easier to push through.

7. Support your fasting protocol with targeted nutrition.
Zenith probiotic taken with your first meal supports the gut-brain axis restoration that the fasting window has been supporting overnight. Organixx Magnesium 7 taken in the evening supports the deep sleep that is both growth hormone's primary release window and the body's overnight fasting recovery period. Baja Gold or Redmond salt in water throughout the fasting window replaces the trace minerals that kidneys excrete more actively in the fasted state. And bone broth on longer fasting days provides structural gut support that accelerates the repair that fasting initiates.

One of the most compelling connections in fasting research is the relationship between fasting and the gut-brain axis.

The migrating motor complex we discussed earlier is the gut's self-cleaning mechanism — and it depends entirely on adequate fasting windows to function. When it operates consistently it reduces bacterial overgrowth in the small intestine, clears accumulated debris from the gut lining, and resets the motility patterns that govern healthy digestion.

Fasting also significantly increases the populations of beneficial gut bacteria — particularly Akkermansia muciniphila, the mucus-layer bacterium associated with gut barrier integrity, metabolic health, and reduced systemic inflammation. Akkermansia thrives during fasting and is one of the most potent markers of gut health improvement in people who adopt intermittent fasting consistently.

The ketones produced during fasting — beyond their direct neurological benefits — support the enteric nervous system by reducing neuroinflammation in the gut-brain communication pathway and improving the vagal tone that governs gut-brain signaling quality.

Fasting is one of the most powerful gut healing tools available. And gut healing is one of the most powerful reasons to fast.

The spiritual practice of fasting is as transformative as the physical one.

Fasting is one of the most ancient spiritual disciplines in human history. Moses and David fasted. Esther and Daniel fasted. Paul fasted. And Jesus — in the wilderness at the beginning of His ministry — fasted for forty days before the most important work of His life began.

Fasting is not mentioned in Scripture as a punishment or a performance. It is presented as a practice — a way of quieting the body's demands enough to hear more clearly, of shifting attention from the physical appetite to the spiritual one, and of creating the stillness in which God speaks to us most directly.

What I have found personally — and what many people who incorporate both the physical and spiritual dimensions of fasting report — is that the mental clarity produced by the fasted state and the discipline of choosing restraint creates a unique quality of attentiveness. The hours of the fast become hours when something else — deeper and quieter — has room to emerge.

"We fasted and petitioned our God about this, and he answered our prayer.”
— Ezra 8:23

Fasting is not just about abstaining from food—it is about drawing closer to God, seeking His guidance, and creating space to hear His voice more clearly.

Your Faith Action Step:
This week — before you begin any fasting protocol — pray over it. Offer the fast specifically to God. Something like: "Lord, I offer this fast to You. May what I do for my physical health also serve my spirit. Use the quiet hours of this fast to speak to me. I am listening." Then notice what those hours hold when they are offered rather than just observed.

Fasting is one of the most ancient and most biologically powerful health practices available. It burns fat, activates autophagy, surges growth hormone, repairs the gut, reduces inflammation, improves metabolic health, and produces the mental clarity that most people spend their lives chasing with caffeine.

It does not require perfection. It requires a starting point — a modest, progressive first step that your body can adapt to — and the consistency to stay with it long enough for the biology to respond.

Start at 14:10. Stay there for two weeks and then extend.

Your body was designed for this. It has been waiting for the space to do its most important work.

Give it that space — and watch what becomes possible.

Your body was designed to thrive. Sometimes it just needs the right building blocks to remember how.

With faith, science, and wellness,
Liz, The Wellness Nurse

Registered Nurse | Certified Mental Wellness Coach

P.S. Have you ever tried intermittent fasting? What was your experience? Hit reply and tell me — I read every response and would love to hear where you are starting from.

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