🥣 The Science of Fasting: What Really Happens to Your Body

Bellingham, Washington

By Jaime J. Hernandez Health and Exercise Prescriptions🛒 Shop Supplements on Thorne

Disclaimer: Always speak to your doctor before beginning any fasting protocol. Fasting can be unsafe for individuals with certain health conditions, including diabetes, eating disorders, or chronic illness. This article is for educational purposes only.

🧬 Why Fasting Deserves a Second Look

Fasting is often misunderstood and mislabeled as extreme or unhealthy. But when done properly and under medical supervision, it can offer profound benefits to your body’s detoxification systems, metabolism, and even mental clarity.

I was inspired by the documentary The Science of Fasting (directed by S. Lestrade, 2016), which breaks down how the human body adapts when food is no longer available. It reminded me that as humans, we evolved during times of food scarcity—fasting is literally hardwired into our biology.

In today’s world, with food available 24/7, our digestive and elimination systems never get a break. That’s where therapeutic fasting comes in.

⚙️ How Fasting Works: The 3-Stage Fuel Shift

When you fast, your body goes through a fascinating fuel-switching process:

1. Stage 1 – Glucose DepletionThe body first burns stored glycogen (glucose) for energy. This lasts about 24 hours.

2. Stage 2 – Fat for Fuel (Ketosis)Once glucose is gone, your body begins to burn stored body fat and produces ketone bodies, which fuel the brain.

3. Stage 3 – Muscle Breakdown (in long fasts)In extended fasts, the body may begin breaking down muscle protein for energy—but it prioritizes fat for as long as possible.

Most healthy adults carry 30–40 days' worth of body fat reserves.

🌪️ Day 3: Entering “The Crisis” Phase

The first 72 hours of fasting are the hardest. Here’s why:

• Your glucose stores drop

• Acidosis sets in (as fat breakdown increases acid levels in the blood)

• Vitamin levels (C, D, E) drop

• You may feel fatigued, nauseated, moody, or experience headaches

This is what fasting practitioners refer to as “The Crisis.” It’s a physical and mental wall—but it typically lasts only 24–36 hours.

The body is essentially learning to feed on itself for the first time.

Urine tests, conducted by your doctor, can confirm when your body enters ketosis or acidosis. After the crisis passes, the body reaches a new balance, and symptoms often improve dramatically.

💧 Supporting the Detox: What Happens After “The Crisis”

Once your body adjusts to fasting, you can begin using supportive therapies to assist in the detox process:

• 🧖 Massage & Hydrotherapy

• 💦 Infrared sauna or hot baths

• 🚶‍♂️ Light movement or walking (2–3 hours/day)

• 🫁 Breathwork to activate lung detox

• 🧴 Colonics or enemas (with professional supervision)

These methods help your liver, kidneys, lungs, and skin eliminate accumulated waste efficiently.

🧠 Mental Clarity & Euphoria

Interestingly, once you pass the initial 3-day hurdle, many people report:

• ✨ Mental sharpness

• 😌 Mood elevation

• 😴 Improved sleep

• 🙏 Emotional release

This happens as the brain adapts to using ketones for energy—a cleaner fuel that can boost cognition and clarity.

Cravings and hunger thoughts fade. You’ll often feel more in tune with your body, and gain awareness of emotional triggers tied to food.

🥄 Breaking the Fast: Do It Carefully

Refeeding after fasting is just as important as the fast itself. The digestive system has been resting—and it needs a gentle reintroduction to solid food.

Recommended first foods include:

• Vegetable broth

• Light soups

• Steamed vegetables

• Small amounts of fruit

• Herbal teas

Avoid processed foods, sugar, or heavy meals. Eating too much too quickly can reverse the benefits of your cleanse and shock your gut.

🧠 Supplement Support for Fasting & Detox

While fasting, your body is under stress and drawing on reserves of vitamins, minerals, and antioxidants. Thoughtfully selected supplements can help support this process.

🛒 Visit My Thorne Supplement Store

My top picks for fasting support:

• Basic Nutrients 2/Day – Replenish vitamins and trace minerals

• MediClear® – Detox support protein powder (for post-fast refeeding)

• Liver Cleanse – Herbal blend to support detox pathways

• Electrolyte Mix – Hydration & mineral support during fast

• Berberine – Supports metabolism & blood sugar regulation

All supplements I recommend are clinical-grade, allergen-free, and 3rd party tested.

🏁 Final Thoughts: Fasting as a Healing Tool

Fasting is not a trend—it’s a powerful ancient practice that can help the body reset, heal, and optimize itself… when done safely and mindfully.

If you’re considering fasting, consult a healthcare provider first, and work with professionals who understand the physiology and emotional process involved.

If you need help with integrating exercise or lifestyle change into your fasting plan, I’m here to support you:

🌐 www.healthandexerciseprescriptions.com🛒 Thorne Supplement Store

Thanks for reading, and thank you for taking the time to invest in your health. Be well,Jaime J. Hernandez Health and Exercise Prescriptions ©