Intermittent Fasting Calculator

Calculate your personalised intermittent fasting schedule based on your lifestyle and goals. Plan optimal eating windows and fasting periods for maximum health benefits.

Create Your Fasting Schedule

Your Personalised Intermittent Fasting Plan

Intermittent Fasting Methods

Intermittent fasting involves cycling between periods of eating and fasting, focusing on when you eat rather than what you eat. Different methods suit different lifestyles and goals.

16:8 Method

Fast for 16 hours and eat within an 8-hour window daily. This is the most popular and sustainable method, often achieved by skipping breakfast and eating between 12pm-8pm.

18:6 Method

Fast for 18 hours with a 6-hour eating window. This method provides enhanced fat burning benefits whilst remaining manageable for most people.

5:2 Diet

Eat normally for five days and consume only 500-600 calories on two non-consecutive days. This method is particularly effective for weight loss and metabolic health.

OMAD (One Meal A Day)

Consume all daily calories within a single meal, typically within a 1-hour window. This advanced method requires careful planning to meet nutritional needs.

Health Benefits

Scientific research demonstrates numerous health benefits associated with intermittent fasting when practised correctly.

  • Weight loss and reduced body fat percentage
  • Improved insulin sensitivity and blood sugar control
  • Enhanced brain function and mental clarity
  • Reduced inflammation markers
  • Lower blood pressure and improved cardiovascular health
  • Increased human growth hormone production
  • Cellular repair and autophagy activation
  • Improved sleep quality and energy levels

Getting Started Tips

  • Start gradually with a 12-hour fast and slowly extend the fasting window
  • Stay hydrated with water, herbal tea, and black coffee during fasting periods
  • Plan nutrient-dense meals within your eating window
  • Listen to your body and adjust your schedule as needed
  • Maintain consistency for optimal results
  • Consider your work schedule and social commitments when choosing an eating window
  • Focus on whole foods, protein, healthy fats, and fibre during eating periods
  • Avoid breaking your fast with sugary or highly processed foods

Managing Hunger and Side Effects

Common Initial Challenges

When starting intermittent fasting, your body needs time to adapt. Common experiences include hunger pangs, mild headaches, and temporary fatigue. These typically subside within 1-2 weeks as your body adjusts to the new eating pattern.

Hunger Management Strategies

  • Drink plenty of water throughout the day to stay hydrated
  • Keep busy during fasting hours to avoid focusing on hunger
  • Consume black coffee or green tea, which can suppress appetite
  • Ensure adequate protein intake during eating windows to promote satiety
  • Get sufficient sleep, as poor sleep increases hunger hormones
  • Practice stress management techniques like meditation or deep breathing

Who Should Avoid Intermittent Fasting

Whilst intermittent fasting is safe for most healthy adults, certain groups should consult healthcare professionals before starting:

  • Pregnant or breastfeeding women
  • Individuals with a history of eating disorders
  • People with diabetes requiring medication
  • Those taking medications that require food intake
  • Individuals with low blood pressure
  • Children and teenagers under 18 years
  • People with chronic medical conditions

Frequently Asked Questions

Can I drink water during fasting periods?
Yes, staying hydrated is essential during fasting. Water, herbal teas, and black coffee (without milk or sugar) are permitted and encouraged during fasting periods.
How long does it take to see results?
Many people notice improved energy and mental clarity within the first week. Weight loss typically becomes noticeable after 2-4 weeks of consistent practice, depending on individual factors and goals.
Can I exercise whilst fasting?
Yes, light to moderate exercise is generally safe during fasting periods. Many people find fasted cardio particularly effective. However, intense workouts may be better scheduled during eating windows when energy levels are higher.
What breaks a fast?
Any caloric intake technically breaks a fast. This includes food, drinks with calories, milk in coffee, or supplements with calories. Stick to water, black coffee, and plain tea during fasting periods.
Is intermittent fasting safe long-term?
For healthy adults, intermittent fasting can be practised long-term safely. However, it’s important to maintain proper nutrition during eating windows and listen to your body’s signals.

References

  1. Varady, K. A., Cienfuegos, S., Ezpeleta, M., & Gabel, K. (2021). Cardiometabolic benefits of intermittent fasting. Annual Review of Nutrition, 41, 333-361.
  2. Liu, D., Huang, Y., Huang, C., Yang, S., Wei, X., Zhang, P., … & Zhang, H. (2022). Calorie restriction with or without time-restricted eating in weight loss. New England Journal of Medicine, 386(16), 1495-1504.
  3. Albosta, M., & Bakke, J. (2021). Intermittent fasting: is there a role in the treatment of diabetes? A review of the literature and guide for primary care physicians. Clinical diabetes and endocrinology, 7(1), 1-12.
  4. Nie, Z., Zhu, H., Zhou, Y., et al. (2023). Effects of time-restricted eating with different eating windows on metabolic health: a systematic review and meta-analysis. PMC10594936.
  5. Berry, S., et al. (2023). 14-hour fasting improves hunger, mood and sleep. King’s College London. European Nutrition Conference.
  6. Semnani-Azad, Z., et al. (2025). Intermittent fasting strategies and their effects on body weight and cardiometabolic health. BMJ, 389, bmj-2024-082007.

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