Choose Your Fasting Protocol
About Intermittent Fasting
What is intermittent fasting? An eating pattern that cycles between periods of fasting and eating. It doesn't specify what foods to eat, but when to eat them.
Popular Protocols
- 16:8: Fast 16 hours, eat within 8 hours. Most popular and sustainable for beginners.
- 18:6: Slightly more restrictive, often a natural progression from 16:8.
- 20:4 (Warrior Diet): Fast 20 hours, eat within 4 hours. Usually 1-2 meals.
- OMAD: One Meal A Day. 23-hour fast with a 1-hour eating window.
Tips for Success
- Stay hydrated: Water, black coffee, and plain tea are okay during fasts
- Start slow: Begin with 12:12, then progress to 14:10, then 16:8
- Be consistent: Same eating window daily helps your body adapt
- Break fast gently: Start with something light, not a large meal
- Listen to your body: Stop if you feel unwell
Frequently Asked Questions
What is intermittent fasting?
Intermittent fasting is an eating pattern that cycles between periods of fasting and eating. It focuses on when you eat rather than what you eat. Popular methods include 16:8 (16 hours fasting, 8 hours eating), 18:6, 20:4 (Warrior Diet), and OMAD (One Meal A Day).
How does the 16:8 fasting method work?
The 16:8 method involves fasting for 16 hours and eating within an 8-hour window each day. For example, if you finish your last meal at 8 PM, you would fast until 12 PM the next day. This is the most popular intermittent fasting protocol for beginners because it's sustainable and effective.
Can I drink water during my fasting window?
Yes, you can and should drink water during your fasting window. Water, black coffee, and plain tea without sugar or cream are allowed during fasting periods. Staying hydrated is essential for successful intermittent fasting.
What is OMAD fasting?
OMAD stands for One Meal A Day. It involves fasting for 23 hours and eating all your daily calories within a 1-hour window. This is an advanced fasting protocol and should only be attempted after successfully adapting to shorter fasting windows like 16:8 or 18:6.
When does fat burning start during fasting?
Fat burning (ketosis) typically begins around 12 hours into your fast as your body depletes its glycogen stores. Between 16-18 hours, autophagy (cellular cleanup) increases. The longer you fast, the deeper into fat-burning mode your body goes, but always consult a healthcare provider before attempting extended fasts.
Is intermittent fasting safe for everyone?
No, intermittent fasting is not suitable for everyone. It is not recommended for pregnant or nursing women, children, individuals with eating disorders, or those with certain medical conditions like diabetes or low blood pressure. Always consult your healthcare provider before starting any fasting regimen.
How long should beginners fast?
Beginners should start with a 12:12 protocol (12 hours fasting, 12 hours eating) and gradually progress to 14:10, then 16:8 as their body adapts. Starting slow helps minimize side effects like hunger, fatigue, and irritability while allowing your body to adjust to the new eating pattern.
What breaks a fast?
Anything with calories breaks a fast, including food, sugar-sweetened drinks, milk in coffee, or protein shakes. Water, black coffee, plain tea, and zero-calorie drinks do not break a fast. Even small amounts of calories (like cream in coffee) can trigger an insulin response and end your fasting state.
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Privacy & Limitations
- All calculations run entirely in your browser -- nothing is sent to any server.
- Results are estimates and should not replace professional medical advice.
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Fasting Calculator FAQ
What is intermittent fasting?
Intermittent fasting is an eating pattern that cycles between periods of fasting and eating. It focuses on when you eat rather than what you eat. Popular methods include 16:8 (16 hours fasting, 8 hours eating), 18:6, 20:4 (Warrior Diet), and OMAD (One Meal A Day).
How does the 16:8 fasting method work?
The 16:8 method involves fasting for 16 hours and eating within an 8-hour window each day. For example, if you finish your last meal at 8 PM, you would fast until 12 PM the next day. This is the most popular intermittent fasting protocol for beginners because it's sustainable and effective.
Can I drink water during my fasting window?
Yes, you can and should drink water during your fasting window. Water, black coffee, and plain tea without sugar or cream are allowed during fasting periods. Staying hydrated is essential for successful intermittent fasting.
What is OMAD fasting?
OMAD stands for One Meal A Day. It involves fasting for 23 hours and eating all your daily calories within a 1-hour window. This is an advanced fasting protocol and should only be attempted after successfully adapting to shorter fasting windows like 16:8 or 18:6.
When does fat burning start during fasting?
Fat burning (ketosis) typically begins around 12 hours into your fast as your body depletes its glycogen stores. Between 16-18 hours, autophagy (cellular cleanup) increases. The longer you fast, the deeper into fat-burning mode your body goes, but always consult a healthcare provider before attempting extended fasts.
Is intermittent fasting safe for everyone?
No, intermittent fasting is not suitable for everyone. It is not recommended for pregnant or nursing women, children, individuals with eating disorders, or those with certain medical conditions like diabetes or low blood pressure. Always consult your healthcare provider before starting any fasting regimen.
How long should beginners fast?
Beginners should start with a 12:12 protocol (12 hours fasting, 12 hours eating) and gradually progress to 14:10, then 16:8 as their body adapts. Starting slow helps minimize side effects like hunger, fatigue, and irritability while allowing your body to adjust to the new eating pattern.
What breaks a fast?
Anything with calories breaks a fast, including food, sugar-sweetened drinks, milk in coffee, or protein shakes. Water, black coffee, plain tea, and zero-calorie drinks do not break a fast. Even small amounts of calories (like cream in coffee) can trigger an insulin response and end your fasting state.