Intermittent Fasting Calculator – 16:8, 5:2, OMAD & More

Intermittent fasting is an eating pattern that cycles between periods of eating and fasting. It focuses on WHEN you eat, not WHAT you eat. Common protocols include 16:8, 5:2, and OMAD. IF is not a diet but rather a dietary pattern that can be combined with any eating style.

16:8 means fasting for 16 hours and eating during an 8-hour eating window. For example, eating between 12 PM and 8 PM, then fasting until noon the next day. This is the most popular protocol for beginners due to its sustainability.

For most healthy adults, IF is safe when practiced correctly. However, consult your doctor if you have diabetes, thyroid conditions, are pregnant or breastfeeding, have a history of eating disorders, or take medications for chronic conditions.

Yes! Water, black coffee, and unsweetened tea don't break a fast because they contain negligible calories. Avoid adding milk, sugar, or cream. Diet sodas are technically calorie-free but may affect insulin response.

Most people notice changes within 2-4 weeks of consistent practice. Results depend on diet quality, calorie intake, exercise, and consistency. Combined with regular exercise and a balanced diet, results typically appear faster.

The 5:2 protocol means eating normally 5 days a week and restricting calories to 500-600 for 2 non-consecutive days per week. For example, fasting on Mondays and Thursdays. This method allows more dietary freedom on non-fasting days.

OMAD stands for "One Meal A Day" - a strict IF protocol where you consume all daily calories in a single eating session, typically lasting 1-2 hours. OMAD is an advanced protocol and not recommended for beginners.

Light to moderate exercise (walking, yoga, strength training) works well during fasting. For intense workouts, it's recommended to break your fast first or exercise during your eating window to ensure adequate energy and recovery.

Muscle loss depends on protein intake and exercise. Consume adequate protein during eating windows and perform resistance training. Most studies show IF preserves muscle when combined with proper nutrition and strength training.