How Many Days Should I Fast Per Week? Finding Your Ideal Fasting Schedule

November 19, 2025 •

4 min read

Research indicates that fasting two days per week may lead to greater weight loss than fasting only one day per week for some individuals. Choosing how many days should I fast per week depends on health goals and lifestyle.

Quick Summary

Deciding on the frequency of weekly fasting involves comparing different methods like the 5:2 and Eat-Stop-Eat approaches. The best method depends on personal goals, such as weight loss, metabolic health and lifestyle. Consistency is a key factor for achieving results.

Key Points

Start Slowly: Begin with less restrictive methods like time-restricted eating before attempting multi-day fasts.
The 5:2 Method: A popular weekly option involving two non-consecutive days of restricted calories (500-600) for weight loss and metabolic health.
Eat-Stop-Eat: For more experienced fasters, this involves one or two full 24-hour fasts per week, which can yield faster weight loss but may cause more intense side effects.
Listen to Your Body: Pay attention to your body's signals and adjust your fasting schedule as needed to ensure sustainability and avoid adverse effects like irritability or fatigue.
Stay Hydrated: Drink plenty of calorie-free fluids like water or herbal tea during fasting periods to prevent dehydration and manage hunger.
Prioritize Nutrition: On non-fasting days, eat a balanced, nutrient-dense diet to provide your body with essential vitamins and minerals.

Determining the Right Fasting Frequency

The question of "how many days should I fast per week?" is a primary consideration for anyone interested in intermittent fasting (IF). The correct answer depends on your objectives. The aims of weekly fasting often include managing weight, enhancing metabolic health, and activating cellular repair mechanisms like autophagy. Research suggests that fasting for at least 12 hours is needed to switch from using consumed carbohydrates to using stored fat for energy. Depending on your goals and tolerance, you can choose various weekly schedules.

Popular Weekly Intermittent Fasting Protocols

Many popular intermittent fasting protocols center on the weekly frequency rather than daily time-restricted eating. These methods allow greater flexibility on non-fasting days.

The 5:2 Method

This method, also referred to as the "Fast Diet," is one of the most widely used weekly fasting routines.

Eat normally and healthfully on five days of the week.
On two non-consecutive days, limit caloric intake to approximately 500-600 calories.
It is advised to space out fasting days, such as fasting on Monday and Thursday, to avoid overstressing the body.
Studies show that this approach can be beneficial for weight loss, improving metabolic markers, and helping to regulate blood sugar.

Eat-Stop-Eat (24-Hour Fast)

Brad Pilon developed this approach, which involves a full 24-hour fast once or twice per week.

Choose one or two non-consecutive days to fast from one mealtime to the same mealtime the next day (e.g., lunch on Wednesday to lunch on Thursday).
During the 24-hour fasting period, you should only consume calorie-free beverages like water, black coffee, or herbal tea.
This approach can be challenging but offers a significant caloric deficit, which can be useful for weight loss.
It is often recommended for individuals with some experience with fasting, and beginners should start with shorter fasts.

Comparison of Weekly Fasting Methods


Feature	5:2 Method	Eat-Stop-Eat Method
Duration	2 days of calorie restriction (500-600 calories)	1-2 days of complete 24-hour fasting
Flexibility	High. Any two non-consecutive days can be selected.	Moderate. Requires a full 24-hour commitment on fasting days.
Weight Loss Potential	Proven effective, potentially greater than fasting one day per week based on some studies.	Can create a significant caloric deficit for accelerated weight loss.
Metabolic Benefits	Promotes fat-burning and improves insulin sensitivity.	Also promotes metabolic switching to fat burning.
Potential Side Effects	Mild hunger, fatigue, and irritability, particularly at the beginning.	More pronounced side effects such as fatigue, headaches, and hunger due to the longer fasts.
Suitable For	Beginners and those who prefer some intake on fasting days.	More experienced fasters seeking more intense results.
Sustainability	Considered flexible and easier to sustain long-term for many.	Can be harder to maintain for long periods due to intensity.

Choosing the Right Fasting Frequency

Deciding on the correct number of fasting days is a personal decision that should be based on your health, goals, and how your body responds. Here's how to decide:

For Beginners: If new to fasting, begin gradually to observe your body's reaction. A 12-hour or 14-hour daily fast (time-restricted eating) is a gentle introduction. Once comfortable, you could try the 5:2 method, as the calorie allowance on fasting days makes it more approachable.
For Accelerated Weight Loss: If your body tolerates fasting well and you aim for more aggressive weight loss, increasing the frequency or duration may be an option. Research suggests that fasting two days a week, such as with the 5:2 diet, may result in greater weight and fat reduction compared to just one day. The Eat-Stop-Eat method is another useful tool, but comes with more intense side effects.
For Metabolic Health and Maintenance: For general health improvement, fasting one or two days per week is often sufficient. Intermittent fasting can reduce inflammation, improve blood sugar regulation, and support heart health. Listen to your body and find a sustainable schedule. Consistency is more important than extreme, short-term efforts.
Considerations: It is crucial to consume a nutrient-dense, healthy diet during your eating periods, regardless of your fasting schedule. Overeating or consuming unhealthy foods on non-fasting days can negate the benefits. Always stay well-hydrated with water or calorie-free drinks during fasts. Remember to consult a healthcare provider before starting any new dietary regimen, especially if you have underlying health conditions or are on medication.

Sustainability and Long-Term Results

Although fasting can be a useful tool, its long-term effects should be considered. Most intermittent fasting research has been short-term, and additional studies are needed to fully understand its long-term health benefits and risks. Building a sustainable plan that does not negatively impact your energy levels or nutrient intake is crucial. The key is to find a routine that you can maintain consistently over time, rather than a regimen that causes significant distress or overeating on non-fasting days. Adjusting your schedule based on personal feedback is more effective than sticking rigidly to a plan that doesn't feel right.

For more evidence-based resources on the different methods of intermittent fasting and how they compare, see this guide from ZOE: Intermittent Fasting Schedule: Methods and How To Do It.

Conclusion

There is no single perfect number of days to fast per week. The best approach is highly individualized, depending on your health goals, experience, and lifestyle. Beginners might start with daily time-restricted eating or the gentle 5:2 method, while more experienced fasters might explore 24-hour fasts once or twice a week. Consistent practice, proper hydration, and a focus on nutrient-dense meals during eating periods are critical for success and safety. Always consult a medical professional before starting, particularly if you have pre-existing health conditions.

Frequently Asked Questions

While fasting two non-consecutive days per week is common in the 5:2 method, fasting two days in a row is generally not recommended, especially for beginners. It can increase the risk of side effects like fatigue and dehydration. Always space your fasting days with at least one normal eating day.

Yes, many people practice daily intermittent fasting using methods like the 16:8 schedule, where you fast for 16 hours and eat within an 8-hour window. This is a form of time-restricted eating and is often more sustainable for beginners than multi-day weekly fasts.

On your 500-600 calorie fasting days, focus on nutrient-dense, low-calorie foods. Good choices include lean protein, non-starchy vegetables, and high-fiber foods to help you feel full longer. Avoid high-calorie, sugary snacks and processed foods.

If you experience significant dizziness, weakness, or irritability, it is important to listen to your body and break your fast. You can always adjust your schedule or choose a less restrictive method. Never force yourself to continue fasting if you feel unsafe.

Yes, your exercise schedule can influence your fasting plan. While moderate exercise during fasting is possible, intense workouts may require adequate fueling. You might choose to fast on less active days and ensure proper nutrition for workouts on eating days. Pay attention to how your energy levels feel.

During a fast, you can and should drink plenty of calorie-free beverages to stay hydrated. Water is essential, and you can also have black coffee or unsweetened herbal teas. Avoid drinks with added sugars, creams, or milk, as these will break your fast.

Intermittent fasting is not for everyone. You should avoid fasting or consult a doctor first if you are pregnant or breastfeeding, have a history of eating disorders, are under 18, have diabetes, or take medication that needs to be consumed with food.