How Long Should You Do Intermittent Fasting?

Intermittent fasting is a popular approach to managing weight and enhancing overall health. The common question, How long can you do intermittent fasting? often arises.

Experts like Jim from the Jim Army and clinical nutritionist Autumn emphasize that intermittent fasting is not just a temporary diet but a sustainable lifestyle choice. Research supports its numerous benefits, including fat loss, improved metabolic rate, and enhanced insulin sensitivity, making it a viable long-term practice.

Different Methods of Intermittent Fasting

Daily Time-Restricted Methods

12-hour or Overnight Fasting

Fast for 12 hours, typically overnight. It’s a simple method that often fits naturally with sleep patterns, making it easy to maintain.

14/10 Fasting

Fast for 14 hours and eat within a 10-hour window. This method balances fasting with a moderate eating period, providing flexibility.

16/8 Fasting

Fast for 16 hours and eat within an 8-hour window. Popularized by experts like Jim, this method is effective for fat loss and maintaining muscle.  

Warrior Diet or OMAD

Fast for 20 hours and eat one meal a day (OMAD). Known as the Warrior Diet, it focuses on a short eating period to maximize fasting benefits.

Calorie-Restricted Methods

Alternate-Day Fasting (ADF)

Eat normally one day, then consume very few calories (about 500) the next. ADF can effectively reduce overall calorie intake.


Eat normally for five days and restrict calories (around 500-600) on two non-consecutive days. This method is flexible and sustainable.

Intuitive Fasting or Skipping a Meal

Skip meals based on your hunger cues. This flexible approach helps you listen to your body and reduce overall calorie intake.

Prolonged and Water Fasting

Fasting for 24-72 hours with water only. Prolonged fasting can reset metabolism and improve insulin sensitivity but should be done cautiously.

The Two Times a Week Method

Fast for two non-consecutive days each week. This method, similar to 5:2, helps reduce weekly calorie intake and supports weight loss.

The Alternate-Day Fasting Method

Similar to ADF, this method involves alternating between normal eating days and fasting days, helping to boost metabolic flexibility and fat burning.

How Long Should You Practice Intermittent Fasting?

Recommended Duration for Fasting Periods

Intermittent fasting can be tailored to fit individual needs, with popular methods like the 16/8 or 5:2 fasting being sustainable long-term.

According to Jim from the Jim Army, fasting daily for 16 hours has allowed him to maintain a lean physique and robust health year-round.

Intermittent fasting has been embraced by many health enthusiasts and experts alike for its ability to support long-term weight management and overall well-being. It not only helps in reducing calorie intake but also in enhancing metabolic processes. The structured periods of fasting and eating can train your body to burn fat more efficiently, leading to sustained energy levels and better health outcomes. The benefits are especially notable when combined with a balanced diet, ensuring that the body receives all the necessary nutrients during eating windows.

“With your hormones in harmony, fasting helps accelerate your metabolic rate—which also allows you to maintain a healthy weight.” said Cynthia Thurlow, NP, and Intermittent Fasting Expert, Lumen

Moreover, intermittent fasting has shown potential benefits beyond weight loss, such as improved insulin sensitivity, reduced inflammation, and better mental clarity. As with any lifestyle change, it’s important to monitor your body’s response and adjust accordingly. By paying attention to your nutrition and listening to your body’s signals, intermittent fasting can become a sustainable and effective tool for long-term health and vitality. Always consult with a healthcare professional to tailor your fasting regimen to your individual health needs and goals.

Clinical nutritionist Autumn highlights that initial results can often be seen within three days to two weeks, depending on dietary habits and metabolic flexibility. 

Research supports that intermittent fasting not only aids in weight loss but also offers numerous health benefits, making it feasible to practice indefinitely as a lifestyle choice. 

If you experience persistent fatigue, dizziness, irritability, or trouble concentrating, it might be a sign to stop intermittent fasting. Also, if you notice a decline in your overall well-being or nutritional status, it’s crucial to reassess your fasting routine. Always listen to your body and consult a healthcare professional if necessary.

Is It Healthy to Continue Intermittent Fasting Indefinitely?

Yes, intermittent fasting can be a healthy long-term practice. Jim emphasizes that it’s a sustainable lifestyle, not just a diet fad. 

As long as you’re getting adequate nutrition during your eating windows, intermittent fasting can be maintained indefinitely, contributing to improved metabolic health, fat loss and overall well-being. 

Considerations for Different Individuals

Who Should Not Do Intermittent Fasting?

Intermittent fasting may not be suitable for everyone. Pregnant or breastfeeding women, individuals with a history of eating disorders or those with certain medical conditions such as diabetes should avoid intermittent fasting without professional guidance. 

According to Autumn, people with low metabolic flexibility or high carbohydrate diets might struggle initially. Always consult with a healthcare provider to determine if intermittent fasting is a safe and appropriate option for your health needs.

When Should You Stop Intermittent Fasting?

Stop intermittent fasting if you experience persistent adverse effects such as extreme fatigue, dizziness, or nutritional deficiencies. 

Autumn suggests paying attention to your body’s signals; if fasting negatively impacts your health or well-being, it’s crucial to reassess your approach. 

Consulting with a healthcare professional can help ensure that intermittent fasting is beneficial and not detrimental to your health.


Intermittent fasting offers a flexible and sustainable approach to weight management and overall health. Key methods include daily time-restricted and calorie-restricted fasting, each adaptable to individual needs.

Experts like Jim and Autumn highlight its long-term viability and numerous benefits from fat loss to improved metabolic health. 

While generally safe for many, it’s essential to consider personal health conditions and consult with a healthcare provider. Embrace intermittent fasting as a lifestyle choice for enhanced well-being and longevity.

Leave a Comment