Fasting Protocols
The oldest metabolic reset tool — just time, intention, and consistency, used thoughtfully.
Fasting gives your body time away from constant digestion so insulin can lower, stored fuel can become easier to access, and your metabolism can practice switching between glucose, fat, and ketones — safely, gently, and at your own pace.
Fasting is not for everyone. Please seek medical guidance if you are pregnant, breastfeeding, under 18, underweight, have diabetes, a history of disordered eating, or take blood-sugar/blood-pressure medication.
Fasting Made Simple
Fasting gives your body time away from constant digestion. As insulin lowers, stored fuel becomes easier to access, ketones may rise, and cellular repair pathways can become more active.
Why Fasting Works
✓ Eating raises insulin → the body stores and uses incoming energy.
✓ Fasting lowers insulin → stored fat becomes easier to access.
✓ The body shifts from digestion to repair and fuel switching.
✓ Ketones may rise, especially during longer fasting windows.
✓ Cellular cleanup pathways, including autophagy, may become more active.
✓ Fasting trains metabolic flexibility — your ability to shift from glucose to stored fat and ketones.
The 5 Phases of a Fast
0–4 hrs: Fed state — your body is digesting and insulin is elevated.
4–12 hrs: Early fast — insulin begins to fall and your body starts using stored glycogen.
12–24 hrs: Fuel shift — glycogen continues to lower, fat burning increases, and ketones may begin to rise.
24–48 hrs: Deeper fast — fat oxidation increases, insulin remains low, and cellular cleanup pathways may become more active.
48–72+ hrs: Extended fast — deeper ketosis and repair pathways may increase, but this is advanced and best done with guidance.
Practical Protocols
12:12: Beginner reset — fast 12 hours and eat within a 12-hour window.
14:10: Gentle transition — fast 14 hours and eat within a 10-hour window.
16:8: Most popular starting point — fast 16 hours and eat within an 8-hour window.
18:6: Deeper metabolic window — best after you are comfortable with 16:8.
20:4: Advanced protocol — requires nutrient-dense meals and enough protein.
5:2: A flexible weekly option — five regular days and two lighter or more structured fasting days.
OMAD / 36–72 hrs: Advanced fasting only, best used carefully and not as a casual default.
Every hour you fast gives your body a break from digestion — and more time for balance, repair, and metabolic flexibility.
Clean Fasting & Gentle Fuel
Fasting is simple during the fasting window — and gentle when you break it. Keep the fast clean, then return to food with intention.
What Doesn’t Break a Clean Fast
During a clean fast, keep it simple: no calories, no sweeteners, and nothing that triggers digestion.
✓ Water or sparkling water
✓ Black coffee
✓ Plain green, black, or herbal tea
✓ Sugar-free, calorie-free electrolytes
How to Break a Fast
Breaking a fast is not about rewarding restriction. It is about giving your body a calm way back into nourishment.
Short fast: under 20 hours: Choose a normal nutrient-dense meal.
Moderate fast: 24–48 hours: Start with something easy to digest and eat slowly.
Longer fast: 48+ hours: Reintroduce food gradually and consider professional guidance.
Optional Pre-Meal
After a moderate or longer fast, a small “first step” before your main meal may help your digestion wake up slowly.
✓ Bone broth
✓ A warm drink with MCT
✓ An egg
Wait about 15–20 minutes, then have your main meal slowly.
Bone broth, collagen, MCT oil, butter coffee, cream, and “just a bite” may support a modified fast — but they break a clean fast.
The first meal is not a reward. It is gentle fuel.
Fasting for Women
Women are not meant to fast the same way every day. Hormones shift, stress changes, sleep matters, and fasting should support the body — not pressure it. This is a general framework, not medical advice — cycles vart. Adjust to your own body and clinician’s guidance.
Women Are Cyclical
Fasting should feel flexible. Some weeks your body may respond well to a longer window, and other weeks it may need more nourishment.
A good fasting rhythm works with your biology, not against it.
Adjust With Your Cycle
Use this as a gentle guide, not a strict rule:
Days 1–10: Menstruation + early follicular phase. Start gentle, then increase only if energy feels good.
Days 11–15: Ovulation window. Many women do better with moderate fasting, steady meals, and enough protein.
Days 16–20: Early luteal phase. Some may still tolerate fasting, but watch sleep, cravings, and mood.
Days 21–28: Late luteal phase. Choose shorter fasts, more nourishment, minerals, and less stress.
Listen to the Signals
If fasting causes poor sleep, anxiety, missed periods, intense cravings, fatigue, or feeling cold all the time, it may be too much.
Pause, shorten the window, nourish well, and reassess.
Perimenopause & Menopause
Gentle and consistent protocols like 12:12, 14:10, or 16:8 may be better tolerated than aggressive fasting. Prioritize protein, minerals, strength training, sleep, and stress support.
The best fasting rhythm is the one that supports your body — not the one that punishes it.
Start Simple — Fast Safely
You do not need to begin with long fasts. Start with a natural overnight fast, finish dinner earlier, avoid late-night snacking, and let your body adapt gradually.
People with diabetes, kidney disease, low blood pressure, gout, pregnancy, breastfeeding, eating-disorder history, or medication use should ask a clinician first.Begin Here:
12 hours overnight — the simplest place to start.
14 hours — once the overnight fast feels natural.
16 hours — only if your body feels well.
Safety note: Fasting is not for everyone. If you are pregnant, breastfeeding, under 18, have a history of eating disorders, take insulin or blood-sugar-lowering medication, or feel dizzy, weak, or unwell while fasting, seek medical guidance before continuing.
When Fasting Becomes Too Much
Fasting is a tool, not a contest. Long or frequent fasts, especially with low calories, high stress, poor sleep, or intense training, can work against the body. If energy, mood, sleep, hormones, cravings, or recovery get worse, shorten the window, nourish well, and reassess.
Your goal is not to eat less forever. Your goal is to teach your body how to use fuel better.
Sources
This platform is built on trusted scientific sources.
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- Malhotra, A. et al. “Saturated fat does not clog the arteries.” BJSM 51(15):1111–1112 (2017)
- Ramsden, C.E. et al. “Re-evaluation of the traditional diet-heart hypothesis.” BMJ 353:i1246 (2016)
- DiNicolantonio, J.J. “The cardiometabolic consequences of replacing saturated fats with carbohydrates.” Open Heart 1(1):e000032 (2014)
- Taubes, G. “Good Calories, Bad Calories.” Anchor Books (2007)
- Fung, J. “The Obesity Code.” Greystone Books (2016)
- Stro, R. & Stro, C. “Dieta Cetogénica / Alimentación Efectiva.” (2019)
