January Longevity Challenge
January 2023 Longevity Challenge - Fasting
Throughout 2023, Zest is running a series of monthly longevity challenges, each based on validated, science-backed protocols for healthier aging.
After indulging throughout the festive season, we think a fast is the perfect way to kick off our 12 months of longevity challenges. We are challenging ourselves and our community to undertake a 24-hour, 48-hour, or 72-hour fast, depending on individual experience, health constraints, and personal preference.
Any length of fast over 24 hours has significant benefits to your health, and will also be a great personal challenge. We will be with you every step of the way to provide motivation, support, and answer any questions which may arise via our longevity challenges Facebook group. In the group you can access key information including our fasting guide with tips and tricks to support beginners to complete at least a 24 hour fast, as well as guides for future challenges, and we will be sharing updates throughout our own fasts.
The benefits of fasting
Short-term
- Improved metabolic health: After around 8 hours without nutrition, your body experiences an initial dip in blood sugar, but your levels stabilize as you begin using glycogen stores from the liver. Studies have shown that even short fasts (less than 24 hours) can reduce insulin resistance, lower blood pressure, and improve cholesterol levels [1].
- Improved cognitive function and focus: Once your body has depleted its stores of glucose (typically around 16-18 hours after last eating) it starts to utilize alternative ways for producing energy, such as ketosis. During ketosis, fat cells are metabolized into ketones which are used as fuel for the muscles and brain, resulting in enhanced mental clarity and focus [2].
- Reduced inflammation and decreased risk of degenerative diseases: Another alternative energy pathway your body uses is autophagy, in which old and damaged cellular components are broken down for nutrition and replaced [3]. Research suggests that fasting-induced autophagy can reduce inflammation [4], suppress cancer [5], and clear away mis-folded proteins associated with Alzheimer’s disease [6].
Medium-term
- Improved immunity: Long fasts appear to have powerful rejuvenating effects on the immune system. Studies show that 72 hours of fasting leads to the formation of new lymphocytes from stem cells in the blood and may be protective against immunosuppressive therapies [7].
- Clearance and inhibition of senescent cells: Fasting is believed to have a lasting effect on senescent cells (or ‘zombie cells’, as they are referred to in Chris Hemsworth’s Limitless TV show). These are harmful cells that cannot replicate but which cannot be removed by the body’s usual mechanisms, and their build up is thought to be a major factor in age-related decline and disease. Fasting can remove senescent cells by starving them of energy and β-hydroxybutyrate, a product of ketosis, can prevent senescent cells accumulating [8].
Long-term
- Lifespan extension via mTOR: Fasting suppresses the mTOR pathway, a series of protein interactions that promote cellular senescence and inhibit autophagy late in life [9]. The suppression of mTOR is therefore thought to be one of the most effective methods for slowing down aging.
- Lifespan extension via sirtuins: Fasting also activates sirtuin genes which are heavily associated with lifespan extension and healthier aging. You can read all about sirtuins and their remarkable impact on longevity in our previous blog post: A Brief Guide to Sirtuins.
The cumulative effect of all these processes means that regular fasting can greatly reduce the risk of cardiovascular disease, cancer, and diabetes, and lead to significantly healthier aging overall.
Zest’s January 2023 fasting challenge
- Beginner: 24-hour fast
- Intermediate: 48-hour fast
- Advanced: 72-hour fast
How long should I fast?
Fasting for 24 hours is sufficient to bring about many of the beneficial effects we have discussed here, particularly when practiced regularly. However, increasing to 48 or 72 hours has a more sustained and powerful effect due to the prolonged action of ketosis, autophagy, and other processes. Studies of extended fasts lasting as long as 10 days have shown some impressive results [13], but these are not recommended without medical supervision.
For this month’s challenge, if you’ve never fasted before then we recommend 24 hours, as this should be achievable for anyone. If you have some experience of fasting, then 48 or 72 hours is a tough but very worthwhile aim!
When to fast
You can do your fast at any time throughout the month of January, but our team will be fasting on the weekend of Jan 21-22 (or Jan 20-22 depending on the length of the fast). We’ll be posting updates to the Zest Longevity Challenges 2023 Facebook group, our Twitter page, and on our website, so if you’d like a little extra motivation, accountability, and discussion, we recommend choosing that weekend too!
What constitutes a fast?
Fasting simply involves ingesting no (or minimal) calories for an extended period of time, generally at least 12 hours. There are different types of fasting with different rules, ranging from nil by mouth (not even water!) to just cutting out certain nutrients. For this challenge, we recommend a calorie-restricted fast. This means you can still drink water, black tea, and black coffee, and take in electrolytes in liquid form, making it the most accessible and effective method of fasting.
Join the community!
Fasting, like any challenge, is much easier with the support of other people, so join our Longevity Challenges for 2023 community where we will be:
- Providing further useful information about fasting (including a step-by-step fasting guide) as well as details about future challenges
- Posting about our own experiences of fasting, including changes to key biomarkers as well as impacts on physical and mental performance
- Answering any questions relating to the healthcare or scientific side of fasting and other longevity challenges - we are a team of doctors and longevity scientists and are excited to share our knowledge!
- Encouraging members to share their own experiences so we can spark discussions and encourage one another.
