Loading...
Loading...
Track your intermittent fasting cycles with a live countdown timer. Supports 16:8, 18:6, 20:4, and OMAD protocols. Saves progress to localStorage with fasting history and stats.
HealthLoading tool...
Calculate your BMR using the Mifflin-St Jeor equation.
Try tool →Find your best bedtime or wake-up time for full cycles.
Try tool →Calculate your TDEE, BMR, and target calories for weight loss, maintenance, or muscle gain.
Try tool →Calculate your body fat percentage using the US Navy circumference method.
Try tool →Find your exact age in years, months, days, and more.
Try tool →Find the number of days between any two dates.
Try tool →Quick percentage calculations for discounts and tips.
Try tool →Find your best bedtime or wake-up time for full cycles.
Try tool →Ready to start your Fast 16h, Eat 8h fast?
Loading...
The most popular and beginner-friendly protocol. Fast for 16 hours and eat all your meals within an 8-hour window. A common approach is skipping breakfast and eating between 12 PM and 8 PM.
A moderate protocol that extends the fasting window to 18 hours with a 6-hour eating window. Often chosen by those who have adapted to 16:8 and want more fasting time for deeper ketosis.
A more advanced protocol with a 4-hour eating window (often called the Warrior Diet). Typically involves one large meal and a small snack within the window.
One Meal A Day — the most intense standard protocol. Eat all your daily calories in a single meal within a 1-hour window. Requires significant adaptation and nutrient-dense eating to meet nutritional needs.
Water, black coffee, and unsweetened tea are generally considered acceptable during fasting windows. Some people also allow bone broth or apple cider vinegar. Anything with significant calories (above ~10-15 kcal) will break the fasted state.
Most people adapt to 16:8 within 1-2 weeks. During the adaptation period, you may experience hunger, irritability, and lower energy. Staying hydrated and keeping busy during the fasting window helps. Start with 12:12 and gradually increase the fasting window.
Research shows that intermittent fasting preserves muscle mass as effectively as traditional calorie restriction when protein intake is adequate (1.6-2.2g per kg of body weight). Strength training during the eating window further protects muscle.
Yes. Many people perform well training in a fasted state, especially for low-to-moderate intensity cardio. High-intensity or heavy strength training is typically better performed during or near the eating window for optimal performance and recovery.
Intermittent fasting is safe for most healthy adults, but not recommended for pregnant or breastfeeding women, individuals with a history of eating disorders, people with diabetes on medication, or those who are underweight. Consult a healthcare professional before starting any fasting regimen.