Intermittent Fasting Calculator

Intermittent fasting (IF) is an eating pattern that cycles between periods of fasting and eating. It doesn't specify which foods to eat, but when to eat them. During fasting, your body depletes glycogen stores and switches to burning fat for energy (ketosis). This metabolic switch triggers cellular repair, autophagy, and hormone changes that promote fat loss and health benefits.

The 16:8 method is ideal for beginners. Fast for 16 hours (including sleep) and eat during an 8-hour window. For example, eat from 12pm-8pm and fast from 8pm-12pm. It's sustainable, flexible, and allows two full meals plus snacks. Start with 14:10 if 16:8 feels too challenging initially.

Yes! Zero-calorie beverages are allowed and encouraged during fasting. Drink water, black coffee, unsweetened tea (green, black, herbal), and sparkling water. Avoid adding sugar, milk, cream, or sweeteners. Black coffee and tea can actually help suppress appetite and enhance fat burning. Stay hydrated with 2-3 liters of water daily.

Yes, IF can promote weight loss by reducing calorie intake and boosting metabolism. Fasting for 12-16 hours shifts your body to burn fat instead of glucose. Studies show IF can reduce body weight by 3-8% over 3-24 weeks. However, weight loss also depends on what you eat during feeding windows - maintain a calorie deficit and eat nutritious foods for best results.

Break your fast with easily digestible, nutrient-dense foods. Start with water or herbal tea, then eat protein (eggs, fish, chicken), healthy fats (avocado, nuts, olive oil), and fiber (vegetables, berries). Avoid high-sugar, processed foods that spike insulin. Good options: Greek yogurt with berries, avocado toast with eggs, or a balanced salad with grilled protein.

IF is generally safe for healthy adults, but not for everyone. Avoid IF if you're pregnant, breastfeeding, under 18, have eating disorders, diabetes (without doctor supervision), or are underweight. People with chronic conditions should consult healthcare providers first. Listen to your body - stop if you experience severe hunger, dizziness, fatigue, or other concerning symptoms.

Most people notice initial changes in 2-4 weeks: improved energy, mental clarity, and modest weight loss (1-2 lbs/week). Significant fat loss and metabolic benefits typically appear after 4-8 weeks of consistent practice. Full adaptation to fasting takes 2-4 weeks as your body adjusts to using fat for fuel. Be patient and consistent for sustainable results.