Looking to put a little extra pep in your spring season? Incorporating a fasting practice might be the answer. Fasting is an age-old practice that has been around for millennia and is used culturally, religiously and seasonally all over the world to cleanse our bodies and minds, increasing our energy and focus. Recently fasting is seeing a resurgence in interest and popularity.
What is fasting? Why are we hearing more about it? And what is it good for?
Simply put, fasting is going extended periods between meals. Fasting methods differ from other forms of dietary interventions in that fasting only restricts when you eat, not what you eat or how much you eat. Fasting done correctly provides many benefits without incorporating meticulous caloric restriction or dietary changes. For this article, fasting will be referring to “wet fasting” – restricting when we eat food but not liquid.
There are two categories of fasting that are divided based on the duration of fast, intermittent fasting or periodic fasting. Intermittent fasting refers to fasting periods of 12hrs-2days, and periodic fasting refers to anything over 2 days.
The common forms of intermittent fasting include the following:
- Alternate day fasting (ADF): Fasting for 24 hours every other day of the week.
- 5:2 Fasting: Fasting for 2 days (or consuming very few calories) each week, followed by 5 days of eating without any restrictions.
- Time-Restricted Feeding (TFR): The most popular form, commonly referred to as “intermittent fasting” confines food intake to 6-12hrs per day, leaving a daily fasting window of 12-18hrs.
Periodic fasting practices are longer in duration and must be monitored more closely by a physician. They include:
- Prolonged water-only fasting: Fasting for 3-21days followed by at least a 7-day refeeding period.
- Fasting mimicking diet: Reducing calories by 70-50% or normal intake for 4-7 consecutive days followed by feeding without restrictions once per month.
So what does fasting do to our bodies?
When we go without food for an extended time (hours to days) our bodies switch from using the consumed energy derived from foods to using our bodies stored energy. Our bodies have evolved two main energy storage reserves, of which the most energy-dense and efficient storage form is fat (adipose tissue). In times of food abundance, our bodies (liver) convert excess calories to fat and store them in our fat/adipose cells for times of food scarcity. Fasting is the most effective way to flip the switch from using consumed energy to stored energy.
The various benefits of fasting?
Training our bodies to switch from stored to consumed energy sources, is like a workout for our metabolism. Having a responsive metabolic system is an essential part of maintaining our health and ageing. Fasting has shown to have many benefits. The most common application for fasting is weight loss. Switching from food energy to stored energy, allows our bodies to access and burn our fat storages. It can take the body several hours to days to make this switch, as the body must first deplete the second major energy storage reserve, “glycogen” stored in the liver. This is because glycogen is energy stored in the form of carbohydrates as opposed to fatty acids in fat. Carbohydrates are less energy-dense but more easily accessible. How quickly one switches energy sources depends on several factors – diet, exercise, genetics and metabolic shape/health. Just like training our physical bodies, when training our physiology it is important to adjust and adapt fasting practices to the individual.
The second most common indication for fasting is for those with early signs of metabolic dysfunction, insulin resistance or type 2 diabetes. When we are in a fasted state our levels of a hormone called insulin drastically decrease. This creates a chemical signal that allows our bodies to make the switch to burning stored fuels and improves the body’s ability to respond to insulin. Fasting practices have been shown to reverse insulin resistance, normalize hemoglobin A1C and improve type 2 diabetes.
The improvements in weight and metabolic health have many other positive effects in our body and thus fasting has been shown to improve many chronic diseases including cardiovascular diseases, certain cancers, neurological conditions, gut health and microbiome diversity, chronic inflammation, improved sleep quality and mental clarity. As the prevalence of these chronic diseases continue to rise, it is not surprising to see why incorporating fasting practices into our lives can help put that spring in our step. On top of all that – it’s free, saves time in our busy schedules and can be combined with any diet!
For more information or to see if incorporating fasting practices into your daily or annual routine is right for you, book an appointment with Dr. Luke to learn more.