Fasting for Weight Loss Calculator

The Fasting for Weight Loss Calculator estimates Recommended Daily Calories based on your biometrics, activity level, and fasting schedule. This tool helps individuals practicing intermittent fasting achieve their weight loss goals safely and effectively. Whether you are starting a 16:8 plan, calculating a target date, or adjusting your deficit for faster results, this calculator provides a clear path to success.

Enter your current weight in pounds (lbs)
Enter your target weight in pounds (lbs)
Enter your height in inches
Enter your age in years

How Recommended Daily Calories Is Calculated

Recommended Daily Calories represents the specific amount of energy you should consume during your eating window to create a deficit for weight loss. To find this number, we first calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which accounts for your age, sex, height, and current weight.

  1. We multiply your BMR by your activity level to determine your Total Daily Energy Expenditure (TDEE), which is how many calories you burn naturally.
  2. We identify the calorie deficit needed to meet your desired weekly weight loss goal (e.g., a 1 lb loss requires roughly a 3,500 calorie weekly deficit).
  3. We subtract that deficit from your TDEE to determine your intake limit, adjusting slightly if you selected to include exercise.

What Your Recommended Daily Calories Means

This number tells you exactly how much to eat within your eating window to reach your goal weight by your target date. It bridges the gap between the discipline of fasting and the science of nutrition to ensure you burn fat efficiently.

  • Conservative Loss (0.5–1 lb/week): If your result is close to your maintenance level, focus on nutrient-dense whole foods. This pace is the easiest to adhere to and helps preserve muscle mass.
  • Moderate Loss (1–2 lbs/week): This range is considered the "Gold Standard" for healthy weight loss. It requires a noticeable deficit but balances speed with sustainability effectively.
  • Aggressive Loss (>2 lbs/week): This indicates a significant calorie cut. You must prioritize high protein intake to prevent muscle loss and manage hunger during fasting periods.

Important

Remember that food quality matters as much as quantity. Empty calories can lead to hunger pangs and energy crashes during fasting windows.

This tool is for informational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider before starting a new diet or fasting regimen to ensure it is safe for your specific health conditions.

Monitoring your progress is essential. If you lose weight faster or slower than expected, adjust your daily intake by 100–200 calories and reassess your plan.

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