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Fasting for Longevity: Exploring the Best Methods for a Longer Life

Does fasting make you live longer? What are the benefits of prolonged fasting? Click here to discover how to do prolonged fasting for longevity.
The GlycanAge Team

Exploring how to live a long, healthy life has been a driving force in human endeavours for centuries. Among the numerous approaches investigated, fasting has emerged as a promising method to promote longevity. 

With its roots in ancient cultures and religious practices, fasting has been practised as a form of spiritual discipline for centuries. Additionally, it has garnered scientific interest in recent years for its potential to extend lifespan and improve overall health.

With the growing interest in the connection between diet and well-being, many people want to know the best fasting methods for longevity. This article draws on scientific research to:

  • Highlight the best fasting methods
  • Investigate the mechanisms by which fasting may contribute to longevity
  • Explore the pros and cons of these fasting methods
  • Provide guidance for individuals considering fasting for longevity
  • Discuss individual factors that should be considered before embarking on a fasting regimen.

Keep reading for a comprehensive analysis of the connection between fasting and longevity.

Types of Fasting Methods

Intermittent Fasting (IF)

Intermittent fasting (IF) is an eating pattern that alternates between periods of fasting and eating without necessarily restricting caloric intake during the eating periods. IF can be further categorised into various methods, with the 16:8 and 5:2 methods being among the most popular.

16:8 Fasting Method

The 16:8 method, also known as the Leangains protocol, entails fasting for 16 hours and restricting the eating window to 8 hours daily. Typically, practitioners skip breakfast and consume their meals between noon and 8 pm. A study on overweight adults showed that the 16:8 method resulted in reduced caloric intake, weight loss and improved insulin sensitivity, factors associated with increased longevity [1].

5:2 Method

The 5:2 method, pioneered by Dr. Michael Mosley, involves eating regularly five days a week and consuming only 25% of the normal daily calorie intake for two non-consecutive days. This approach has been shown to benefit weight loss, insulin sensitivity and inflammation, all of which can contribute to a longer, healthier life [2].

Periodic Fasting

Periodic fasting consists of abstaining from food for extended periods, typically lasting between two and seven days, once or twice a year. Research suggests that periodic fasting can stimulate cellular repair processes, such as autophagy, which eliminates damaged cells and reduces the risk of age-related diseases [3]. 

Fasting Mimicking Diet (FMD)

Developed by Dr. Valter Longo, the Fasting Mimicking Diet is a scientifically-designed meal plan that replicates the effects of fasting while still allowing for the consumption of specific low-calorie, plant-based foods. 

The diet consists of a five-day cycle, repeated two to six times a year, and aims to promote longevity by reducing inflammation, improving metabolic markers and stimulating autophagy. 

A study conducted on mice demonstrated that FMD increased lifespan, reduced tumour incidence and improved cognitive function [4]. Furthermore, a pilot study in humans showed that three cycles of FMD led to reduced risk factors for ageing, diabetes and cardiovascular disease [5].

Alternate-Day Fasting (ADF)

Alternate-day fasting involves eating as much or as often as desired on one day, followed by a complete fast or a very low-calorie intake (about 25% of the daily requirement) on the next day.

This pattern is repeated alternately, resulting in a fasting frequency of three to four days per week. Studies on ADF have shown promising results in terms of weight loss, cardiovascular health and insulin sensitivity. 

A 12-week randomised controlled trial of ADF in obese adults demonstrated significant reductions in body weight, waist circumference and blood pressure, along with improved lipid profiles [6]. These improvements can contribute to a decreased risk of age-related diseases and promote longevity.

Time-Restricted Feeding (TRF)

Time-restricted feeding limits the daily eating window to a specific number of hours, typically between six and 12 hours. Unlike the 16:8 method of intermittent fasting, TRF can be tailored to suit individual preferences and schedules, making it a more flexible approach. 

Studies on TRF have revealed improvements in weight management, insulin sensitivity and inflammation. In a controlled trial, prediabetic men who observed a TRF schedule with a 12-hour eating window for five weeks experienced enhanced insulin sensitivity and cell responsiveness and reduced blood pressure, oxidative stress and appetite [1].

Religious Fasting

Various religious practices involve fasting, and these rituals can also offer longevity benefits. For instance, the Islamic practice of Ramadan entails fasting from dawn to sunset for a month, while the Christian tradition of Lent involves abstaining from certain foods for 40 days. 

Studies on individuals who observe Ramadan have shown improvements in body weight, blood pressure and lipid profiles, which can enhance longevity [7]. Moreover, a study on Greek Orthodox Christians who followed fasting practices during Lent demonstrated reduced inflammation and improved cardiovascular risk factors [8].

Can Fasting Help You Live Longer?

Fasting has been shown to have the potential to help individuals live longer by promoting various health benefits. The above-mentioned fasting practices can result in weight loss, improved metabolic health, enhanced insulin sensitivity and reduced inflammation, ultimately contributing to a reduced risk of age-related diseases.

Studies on fasting have also demonstrated its potential to stimulate cellular repair processes like autophagy, which helps eliminate damaged cells and may protect against age-related diseases. Furthermore, fasting has been linked to the activation of certain genes and cellular pathways that promote longevity.

For instance, in a 2010 study, researchers explored the role of autophagy in the effects of caloric restriction and fasting on cancer cells. They observed that fasting-induced autophagy led to the selective death of cancer cells while protecting normal cells, suggesting that fasting could potentially be used as a therapeutic intervention for cancer patients [9].

Moreover, in another study conducted on mice, researchers investigated the effects of short-term fasting on the induction of autophagy in the brain. They found that 24-hour and 48-hour fasting periods significantly increased the number of autophagic vesicles in neurons, indicating that fasting stimulated neuronal autophagy. This finding suggests that fasting-induced autophagy may help protect the brain against neurodegenerative diseases [10].

While this evidence suggests that fasting has the potential to promote longevity, adopting a balanced lifestyle, including a healthy diet, regular physical activity and stress management, is crucial for overall well-being and life extension.

Further research is needed to fully understand the mechanisms behind fasting-induced autophagy and its long-term effects on human health and longevity.

What Are the Pros and Cons of Prolonged Fasting?

Fasting offers several potential health benefits,  but it also has some drawbacks. Here are some of the pros and cons of fasting:

Benefits of prolonged fasting

  1. Weight loss: Fasting can help with weight loss by reducing caloric intake, improving metabolism and promoting fat breakdown for energy.
  2. Improved insulin sensitivity: Fasting has been shown to increase insulin sensitivity, which can help prevent or manage type 2 diabetes.
  3. Enhanced autophagy: Fasting stimulates the cellular process of autophagy, which helps eliminate damaged cells and may protect against age-related diseases.
  4. Reduced inflammation: Fasting can decrease inflammation, which is associated with various chronic diseases and ageing.
  5. Cardiovascular health: Some fasting methods have been linked to improved blood pressure, cholesterol levels and other cardiovascular risk factors.
  6. Cognitive benefits: Fasting may positively affect cognitive function, possibly by promoting the production of brain-derived neurotrophic factor (BDNF), which supports the growth and survival of neurons.
  7. Increased longevity: Fasting may contribute to a longer life by promoting weight loss, metabolic health and cellular repair processes.

Drawbacks of prolonged fasting

  1. Hunger and irritability: Fasting can lead to hunger, irritability and mood swings, especially during the initial adjustment period.
  2. Reduced energy levels: Some individuals may experience fatigue, weakness or dizziness during fasting, particularly if they are not adequately hydrated or have low blood sugar levels.
  3. Potential nutrient deficiencies: Prolonged fasting or extreme caloric restriction could result in nutrient deficiencies if not properly managed.
  4. Loss of muscle mass: Fasting, especially when combined with inadequate protein intake, could lead to loss of muscle mass.
  5. Unsustainable for some: Some individuals may find it challenging to adhere to fasting regimens long-term, which could reduce the potential benefits.
  6. Not suitable for everyone: Fasting may not be appropriate for pregnant or breastfeeding women, children, the elderly or individuals with certain medical conditions, such as diabetes or eating disorders.
  7. Possible negative effects on metabolism: Prolonged fasting or very low-calorie diets may cause the body to enter "starvation mode", potentially leading to a slowed metabolism and making it harder to lose weight.

It is essential to consult with healthcare professionals before embarking on any fasting regimen, particularly for individuals with pre-existing medical conditions. The pros and cons of fasting may vary depending on individual circumstances, and it is crucial to find a fasting method that suits one's lifestyle and health needs.

Who Is Fasting Not Suitable For?

Fasting is not suitable for everyone, and certain individuals should avoid fasting or consult a healthcare professional before attempting it. People who should generally avoid fasting include:

  • Pregnant and breastfeeding women
  • Children and adolescents
  • Elderly individuals
  • Individuals with eating disorders
  • People with diabetes
  • People with low blood pressure (hypotension)
  • Individuals with compromised immune systems
  • People with certain medical conditions
  • Individuals taking prescription medications
  • Athletes or individuals with high physical activity levels.

If you are unsure whether fasting is appropriate for you, it is best to consult a healthcare professional to discuss your individual circumstances and potential risks before embarking on a fasting regimen.

How Long Is It Healthy to Fast?

Long-term fasting safety depends on the specific fasting method, individual factors and proper nutrition management during eating periods. Some forms of intermittent fasting, such as the 16:8 or the 5:2 method, can be safely practised over the long term as long as individuals consume a well-balanced diet during their eating windows to ensure they meet their nutritional requirements.

However, long-term fasting involving prolonged periods without food, such as extended water fasts or very low-calorie diets, can be risky and should be approached with caution. Factors such as age, health status and pre-existing medical conditions can influence whether fasting is safe and beneficial for an individual in the long term.


While research on fasting and longevity continues to evolve, current findings suggest that incorporating fasting methods may contribute to a healthier and longer life when done safely and sustainably. 

Various fasting techniques, such as intermittent fasting, periodic fasting and fasting-mimicking diets, offer unique benefits and challenges, making it essential for individuals to choose a method that aligns with their health goals and personal preferences.

Consulting a healthcare professional before embarking on a fasting regimen is highly recommended, particularly for individuals with pre-existing medical conditions or those on medications.

Take Control of Your Health with GlycanAge

An additional factor to consider in the context of longevity is the GlycanAge test. GlycanAge measures age-related changes in the glycosylation of immunoglobulin G (IgG) molecules, serving as a biomarker of biological age. 

Unlike chronological age (the number of years since birth), biological age (the age of cells within the body) reflects an individual's overall health status and the level of inflammation in their body, making it a valuable tool for assessing the effectiveness of health interventions, such as fasting.

All it takes is a finger-prick blood test in the convenience of your home to learn your biological age. Results are available in as little as three weeks of mailing your sample to our lab. 

A single GlycanAge test can provide key insights into your current health status and potential risks for age-related diseases. Alternatively, two tests can allow you to track the effectiveness of lifestyle changes, such as fasting, dietary adjustments or exercise routines, on your biological age and overall health.

With each test purchased, you also get a complimentary one-to-one session with a healthcare professional to develop personalised strategies for improving your health and potentially extending your lifespan.

Invest in your health and order your GlycanAge home test kit today.


The GlycanAge Team

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