⏱️ Intermittent fasting reduces body fat by 3-8% over 3-24 weeks. 16:8 fasting also improves insulin sensitivity by 20-31% and triggers autophagy (cell cleanup) after 16+ hours. Track your windows and build streaks for free. Why nutrition science matters →
Fasting Tracker
Track your intermittent fasting windows, monitor fasting zones, and build streaks.
Active Fast
Eating window opens at
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00:00:00
remaining
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0-4h
4-16h
16-24h
24-48h
Anabolic (0-4h)
Catabolic (4-16h)
Fat Burning (16-24h)
Deep Ketosis (24-48h)
Stats
Avg Fast
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hours
Longest Fast
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hours
Total Fasted
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hours
History
No fasts recorded yet. Start your first fast above.
Frequently Asked Questions
What is intermittent fasting and how does it work?
Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. It doesn't specify which foods to eat but rather when you should eat them. The most popular methods include 16:8 (16 hours fasting, 8 hours eating), 18:6, 20:4, and OMAD (One Meal A Day). During fasting, your body shifts from using glucose to burning stored fat for energy, a process called metabolic switching.
What are the different fasting zones and what happens in each?
Fasting progresses through several metabolic zones: The Anabolic zone (0-4 hours) is when your body digests and absorbs nutrients. The Catabolic zone (4-16 hours) is when blood sugar and insulin drop and your body begins using stored glycogen. The Fat Burning zone (16-24 hours) is when glycogen is depleted and your body primarily burns fat. Deep Ketosis (24-48 hours) is when ketone production increases significantly, enhancing autophagy and cellular repair.
Which intermittent fasting protocol is best for beginners?
The 16:8 method is widely recommended for beginners because it aligns well with natural eating patterns — you can simply skip breakfast and eat between noon and 8 PM. It provides meaningful metabolic benefits while being sustainable long-term. Once comfortable, you can gradually extend to 18:6 or 20:4 protocols for greater fat-burning benefits.
What can I consume during a fasting window?
During a fasting window, you can consume water, black coffee (no sugar or cream), plain tea, and sparkling water. These beverages have zero or negligible calories and won't break your fast. Anything with calories, artificial sweeteners, or flavoring can trigger an insulin response and potentially break your fast. Staying well-hydrated is especially important during fasting periods.
How do I track fasting streaks and why do they matter?
A fasting streak counts consecutive days you've completed your chosen fasting protocol. Streaks matter because consistency is key to seeing results from intermittent fasting — your body adapts and becomes more efficient at metabolic switching over time. This tracker automatically records completed fasts, calculates your current streak, and shows statistics like average fast length and total fasting hours to keep you motivated.