Fasting is an ancient healing practice that many cultures around the world have utilized in different ways for various reasons. It’s becoming more popularized in western culture, but there’s still a lot of confusion and misinformation around the healthiest ways to fast.

In the simplest terms, fasting is the practice of abstaining from food (and most drink) for a particular period of time. A fasting period can be as short as 16 hours or as long as a number of days or weeks. The method and approach that works best for you depends on your gender, hormone profile, genetics, medical history and personal goals, so it’s important to first take a look at your intentions, habits and needs before embarking on a fast. Intermittent fasting typically gets all the attention, but there are other methods that might be a better fit, depending on the aforementioned factors.

Why do people fast?

These are some of the most common goals:

  • develop or deepen a spiritual practice
  • lose weight
  • improve sleep, energy and mood
  • improve heart health and blood sugar levels
  • cancer prevention
  • reduce inflammation in the body
  • detoxification
  • promote longevity

It’s important to mention that fasting doesn’t need a big goal attached to it; in fact, the more you can release your expectations around the results, the more open your body and mind will be to the changes you need most. If nothing else, fasting creates a container for reflection. It allows us to look at our own relationship with consumption and the energetic push and pull of existing in the world. It invites us to be more mindful of our choices, not only around the food we put into our bodies (when, what and why we’re eating), but also with the energy we give and receive, the ideas and feelings we give weight to, what we choose to hold on to and what we’re willing to release. This is an opportunity for deep rest, renewal, growth and a mind-body reset, an invitation to slow down and observe, and a container to reflect upon our choices, habits, and behaviours to determine what’s truly serving us and what needs to be left behind. 

“How you digest food is a reflection of how you digest life.” 

– Dr. Sonya Jensen, ND


These are the most common types of fast:

  • Intermittent Fasting (IF) – limiting intake to a specific period of time; most people start with the 16/8 model, which entails fasting for 16 hours and eating during the 8-hr window. 
  • 5:1:1 Fasting – practice intermittent fasting on the 5 days (to stimulate ketosis), followed by a refeed day, and then a 24-hr fast
  • Partial Fast – this typically entails including one liquid and one solid twice over a 6-hour timeframe, keeping calories between 500 and 800
  • Fasting Mimicking Diet – developed by Dr. Valter Longo, this method is similar to a partial fast (with stricter guidelines) and focuses on the distribution of macronutrients to encourage autophagy
  • OMAD – eating only One Meal A Day (usually midday or dinner)
  • Bone Broth Fast – only bone broth is consumed during the desired fast period
  • 24-hr Fast – abstaining from food for a period of 24 hours
  • Water fast – only water is consumed during the fasting period (length of fast will vary)
  • Dry fast – no food or water is consumed during the fasting period (length of fast will vary)

*a dry fast and water fast should only be taken on under the supervision of a doctor

Now that we’ve looked at some of the reasons for fasting and the different fasting options, let’s take a look at the science behind this practice.

What is ketosis?

Glucose is like wood-burning energy; it’s depleted quickly, and we have to keep refuelling in order to use more. As glucose rises, so do insulin and cortisol. This combination of hormones creates brain fog, dysfunction in brain cells and the nervous system, and a greater energetic investment in survival rather than healing and renewal. 

Ketones, on the other hand, provide cleaner, more efficient energy (like an electric stove) that maintains healthy brain cell metabolism, improves insulin sensitivity, and helps to release stubborn weight. We have a lot of fat stores around organs and subcutaneous tissues; fasting will tap into this latent energy source, utilizing these fat stores for energy rather than relying on that quick-burning glucose.

What is autophagy?

Autophagy is the natural physiological mechanism of clearing debris and damaged cells to encourage cellular repair. Autophagy is a self-preservation process that supports longevity, and typically kicks in between 2-4 days of fasting. Autophagy happens naturally on a daily basis, but if we’re in a state of inflammation or contending with toxic overload, this process is somewhat inhibited. With the body in more of a sugar-burning state, not as much energy will be utilized in this cellular cleansing process and healing will happen more slowly. Fasting upregulates autophagy, more effectively clearing toxins and waste that may otherwise lead to neurodegenerative disease.

Around day 5 of a fast, there is a surge in stem cell renewal; however, fasting for just 24 hours has been shown to improve the regenerative ability of stem cells¹, aid in healing tissue, and reduce inflammation. Fasting is a restorative practice that is known to heal old injuries, reestablish healthy cell culture and improve homeostasis in our tissues, and reduce the likelihood of age-related pathologies.

4 more reasons to fast:

  1. Create energy diversion – The practice of fasting will take energy that is typically spent on digestion and shift it toward areas that need healing. It stimulates more mitochondrial production and improves its function in our cells, leading to improved energy production and overall health.² Digestion requires a fair amount of energy; when we fast, the energy that would typically be used on this process can be redirected to healing chronic issues.
  2. Support hormone optimization – in peri-menopause and menopause, there is a tendency to move toward insulin resistance. This often causes increased weight around the waistline and wreaks havoc on our sex hormones: estrogen, progesterone and testosterone. Fasting cleans up debris around our cells, helping to optimize hormones and improve the efficiency of their communication. This process downregulates insulin and glucose so our sex hormones are better able do their jobs. Fasting has also been shown to significantly increase human growth hormone (HgH), which is an important hormone involved in cell repair, metabolism, and muscle recovery.³
  3. Reset your DNA – Epigenetics is a rapidly growing area of science that accounts for environmentally controlled gene expression.When we get stuck in a state of inflammation or disease, we’re activating genes that are propagating the source of illness in the body. Toxic substances, trauma, and infection can turn on the genes responsible for disease, while fasting allows us to program our gene expression in a different way, signaling the body to move into a healing state.
  4. Reframe nourishment – This is one of the mindset benefits of fasting. The fast helps to starve the bad bacteria and reset the gut microbiome over 3-5 days. When we begin to refeed, we tend to be more mindful of the nutrients we choose to fuel ourselves with. We’re always feeding the microbiome with the foods we consume, and sometimes an imbalance occurs when the bad bacteria are getting too much energy while the good bacteria are not receiving enough. Fasting helps us to clean up the gut microbiome, ridding the body of those unwanted guests like pathogens, bad bacteria, viruses, parasites, and fungus that may be thriving as a result of our food choices.

The Importance of Refeeding

Your refeeding week is arguably the most important part of a fast. When you begin to put food back into your body, it’s critical that you’re strategic and selective about what you eat. We need to start with a low caloric input for the first couple of days post-fast (approximately 500-800 calories for women and 800-1000 for men), ideally begin with liquids and healthy fats, and slowly start to incorporate cooked and fermented foods. As you near the end of the week, you can begin adding raw foods to your diet, always being mindful of how your body responds to the foods you choose. The primary focus here should be creating more diversity of healthy bacteria in the gut microbiome by making supportive food choices.

After all that you’ve accomplished over the course of your fast, ask yourself this critical question: Am I going to refuel with love or fear? Rather than attaching to the negative aspect of a fast (what we’re losing, avoiding, or sacrificing), let’s instead look at what we’re gaining from this powerful healing process.

Fasting made simple

Our Metabolic Upgrade Program is typically offered seasonally, as the practice of fasting is well-aligned with the transitional period of changing seasons. Depending on the time of year, as well as your own Dosha (or Ayurvedic constitution), your unique needs and best practices with fasting may differ somewhat through the seasons. This is also an opportunity to deepen our connection with nature, as well as to examine our relationships with food, activity, thought processes and patterns, and the people in our lives.

If you’d like to learn more about fasting and how to prepare yourself for a healthy fast, sign up for our 4-week online Metabolic Upgrade program in the Health Ignited Club. 



  1.,both%20aged%20and%20young%20mice. – Anne Trafton, MIT News Office, May 2018
  2. – Fasting and Mitochondrial Health, The Institute for Functional Medicine
  3. – Rudy Mawer, Healthline, September 2019