Short vs long fasts: What is the ideal length for longevity?

Fasting has sparked interest and debate among experts and enthusiasts alike. This age-old practice, rooted in various cultural and historical traditions, is now at the forefront of modern health discussions.

The core question we’re exploring today: What’s the ideal fasting duration for enhancing longevity?

Both approaches have their proponents and detractors, and each comes with its own set of benefits and challenges.

Through this blog, we aim to sift through the research and opinions to provide you with a clear, balanced view.

Whether you’re a fasting novice or a seasoned practitioner, this guide aims to arm you with the knowledge you need to make informed decisions about fasting for health and longevity.

What is short-term and long-term fasting?

When it comes to fasting for health and longevity, there’s an ongoing debate about the effectiveness of short versus long fasts [1].

Both approaches have their advocates and critics, and it’s crucial to understand how they stack up against each other. 

This comparison will look at various factors, from ease of adherence to health impacts, helping you to make an informed decision about which fasting method might suit you best.

Ease of adherence and lifestyle compatibility

Choosing between short and long fasts often boils down to how well they fit into your daily life. Here’s a quick look at how each stacks up in terms of ease of adherence and lifestyle compatibility:

Short fasts:

  • More user-friendly, easily blending into most routines.
  • Ideal for those with busy schedules or social commitments, as you can plan eating windows around your day.
  • Less likely to interfere with family meals or social gatherings.
  • Generally easier to maintain over the long term, making them a practical choice for continuous health management.

Long fasts:

  • Require a greater level of commitment and planning.
  • Can be challenging to integrate into a hectic lifestyle or for those with demanding social or work commitments.
  • May necessitate significant changes to your daily routine, especially for beginners.
  • Often seen as more of a periodic health ‘reset’ than a consistent lifestyle choice.

Ultimately, the best fasting approach is one that aligns seamlessly with your lifestyle, ensuring you can stick with it consistently for the best results.

Ease of adherence and lifestyle compatibility

Immediate health effects

Fasting, whether short or long, brings about immediate health effects that are worth considering:

Short fasts:

  • Typically lead to weight loss, especially when combined with a balanced diet and regular exercise.
  • Improve blood sugar control, a significant benefit for those monitoring their glucose levels.
  • Boost heart health by potentially lowering blood pressure and improving cholesterol levels [2].
  • Many report enhanced mental clarity and energy, though this varies from person to person.

Long fasts:

  • Promote deeper detoxification processes in the body, aiding in the removal of toxins.
  • Can lead to more substantial weight loss, though it’s essential to approach this safely.
  • Offer significant benefits in reducing inflammation, which is linked to many chronic diseases.
  • Some find that they experience a profound sense of physical and mental rejuvenation post-fast.

Both short and long fasts trigger changes in your body, but it’s crucial to approach them with an understanding of their distinct impacts and your personal health goals.

Impact on longevity

The impact of fasting on longevity is a fascinating area of study, with both short and long fasts showing potential benefits:

Short fasts:

  • Regularly practicing short-term fasting can reduce key aging factors like inflammation, obesity, and high blood pressure.
  • These fasts help regulate blood sugar levels and improve metabolic health, both crucial for a longer, healthier life.
  • The consistency of short fasts means you’re continually reaping these benefits, potentially contributing to increased longevity.

Long fasts:

  • Long fasts are known for deeper health impacts, including enhanced cellular repair and autophagy – the body’s way of cleaning out damaged cells.
  • These processes are believed to play a significant role in slowing down the aging process.
  • However, the long-term effects of frequent prolonged fasting need more research to fully understand their impact on lifespan.

Both fasting methods offer promising avenues for those looking to improve their health and potentially extend their lifespan. The key is finding a fasting rhythm that works harmoniously with your body and lifestyle.

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Potential risks and downsides

While fasting has its benefits, it’s important to be aware of the potential risks and downsides:

Short fasts:

  • Generally safe, but some people may experience headaches, dizziness, or irritability, especially when starting.
  • Important to eat balanced meals during non-fasting periods to prevent nutritional deficiencies.
  • Overeating during eating windows can negate the benefits of the fast.

Long fasts:

  • Higher risk of nutrient deficiencies and muscle loss due to extended periods without food.
  • Can lead to electrolyte imbalances, which are critical for heart and muscle function.
  • Not suitable for everyone, especially those with certain health conditions, pregnant women, or individuals with a history of eating disorders.
  • Always recommended to undertake long fasts under medical supervision.

Both short and long fasts come with their own set of challenges, and it’s crucial to listen to your body and consult with a healthcare professional to ensure you’re fasting safely and effectively [3].

Nutritional considerations

Fasting, whether short or long, demands thoughtful nutritional considerations to ensure your body gets what it needs:

Short fasts:

  • Focus on nutrient-dense foods during eating windows to maximize health benefits.
  • A balanced diet rich in vegetables, lean proteins, healthy fats, and whole grains supports overall health and replenishes nutrients.
  • Avoid the temptation to overeat or indulge in unhealthy foods, which can offset the benefits of fasting.

Long fasts:

  • More complex, requiring careful planning to ensure nutritional needs are met before and after fasting.
  • Post-fast, it’s crucial to reintroduce foods slowly and mindfully to avoid digestive issues.
  • Nutritional supplements may be necessary to compensate for extended periods without food, but only under professional guidance.

Regardless of the fasting length, staying hydrated is essential. Water, herbal teas, and in some cases, electrolyte solutions, can help maintain hydration levels, especially during longer fasts. 

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What are the safety tips for fasting?

Embarking on a fasting journey requires careful consideration and preparation to ensure it’s done safely and effectively [4]. Here are some guidelines to help you fast in a way that supports your health and well-being:

1. Understand your health status

Before jumping into fasting, it’s crucial to know where you stand health-wise:

  • Schedule a check-up with your healthcare provider. Discuss your fasting plans and any underlying health concerns.
  • Pay special attention if you have conditions like diabetes, high blood pressure, or heart issues. Fasting can significantly affect these conditions.
  • If you’re pregnant, breastfeeding, or have a history of eating disorders, fasting might not be advisable.
  • Get a professional’s insight on how fasting could interact with any medications you’re taking.

2. Plan your eating windows carefully

Planning your eating windows during short fasting periods is key to success:

  • Choose times that sync well with your daily routine. This makes sticking to your fasting schedule easier [5].
  • Focus on balanced, nutritious meals. Include a mix of vegetables, lean proteins, healthy fats, and whole grains.
  • Resist the urge to overeat. After fasting, start with a small meal and slowly increase to your regular portion size.
  • Treat your eating window as a time for nourishing your body, not just filling it. Quality matters as much as quantity.

3. Break your fast gently

Breaking your fast gently is crucial, especially after long fasting periods:

  • Start with something light and easy to digest, like a small serving of fruits or a warm broth.
  • Gradually reintroduce other foods over the next few meals. Think simple and wholesome.
  • Listen to your body’s cues. If something feels off, take it slower.
  • Stay hydrated, but avoid drinking large amounts of water right before or after eating to aid digestion.
  • Remember, your digestive system needs time to wake up. Treat it kindly to avoid discomfort.
break your fast gently

4. Balance exercise and fasting

Balancing exercise with fasting is a game of understanding your body’s energy levels:

  • Opt for light to moderate exercises, like walking or gentle yoga, especially during longer fasts.
  • If you’re into more intense workouts, try to schedule them during your eating windows when you have more energy.
  • Listen to your body. If you feel weak or dizzy, dial back the intensity or take a break.
  • Staying hydrated is key, especially if you’re exercising during fasting periods [6].
  • Post-exercise, make sure your next meal is nutritious to aid recovery and replenish energy.

5. Stay hydrated

Staying hydrated is crucial during fasting:

  • Drink plenty of water throughout the day, not just during eating windows.
  • Herbal teas and broths can be good, comforting options.
  • Avoid caffeinated drinks as they might lead to dehydration.
  • Listen to your body – if you feel thirsty, drink up.


Remember that fasting is a personal journey that requires tuning into your body’s needs and responses.

Whether you’re leaning towards short or long fasts, or somewhere in between, the key is to approach it with care, mindfulness, and a willingness to adjust based on your experiences.

Fasting can be a powerful tool for enhancing your health and well-being. With the right approach and mindset, you can discover a fasting rhythm that works best for you. So, take that first step, be patient with your progress, and embrace the journey to a healthier you.


What is the healthiest length of time to fast?

The healthiest fasting duration varies per individual, but generally, short fasts like 16-24 hours are widely considered safe and sustainable for most people.

Are long fasts better than short fasts?

Long fasts have the potential for deeper health benefits but come with greater risks, making short fasts often preferable for their balance of safety and health improvement.

How often should I fast to improve my longevity?

The frequency of fasting should be based on individual health goals and lifestyle, with regular short fasts being more sustainable and long fasts considered for occasional deeper health resets.

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The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.