The Many Faces of Fasting

Sep 03, 2021


Fasting has been receiving lots of attention in the media these days. US News and World Report lists “intermittent fasting” as one of the top 10 most popular diets of 2020, and chances are, you likely know of at least one person singing its praises. But before you write off fasting as just the latest fad diet, you should know that its use is nothing new. Even Hippocrates, widely considered to be the “father of modern medicine,” was said to be a proponent of fasting. Fasting has also been in use as a spiritual tool in religions around the world, including the Greek Orthodox Christians, a religion that dominates the regions of Greece studied for their healthy “Mediterranean diet.” 

In recent years, fasting practices have gained popularity as a tool for weight loss and fat-burning and are even thought to have beneficial effects for diabetics and others suffering from chronic inflammatory diseases. So what is fasting, and why might it be beneficial? And better yet, is it right for you? 

Download my Ultimate Guide to Fasting here!

Bookcover for the Ultimate Guide to Fasting

What is Fasting?

Fasting is the voluntary withholding of food that leads to an adaptive response in the body. Some refer to this response as “metabolic switching.” When we eat, our bodies break down the food to be used as fuel (energy), and whatever we don’t use for energy is stored for later use. Glucose is stored in small amounts in the liver and muscles as glycogen for use when “quick fuel” is needed. When these two storage areas are full, excess glucose is stored in fat cells. Ideally, when we are fasting, our bodies are able to “tap into” this stored energy to keep us going. During prolonged fasting periods, stored fats (triglycerides) are broken down into fatty acids, which can be converted to ketones by the liver. Ketones can then be used as an energy source by the body. In a fed state, ketone levels are very low but can begin to rise within 8-12 hours after the onset of fasting and can continue to increase for 24-48 hours with no food. Our human ancestors, who lacked the 24-7 access to food that we have today, developed an adaptive response to food deprivation that enabled the body to conserve energy and trigger pathways to “clean up” worn-out cells and cellular debris, hence making the body more resilient to subsequent periods of stress or scarcity of food. 

The Different Types of Fasting

small bites of food on a wooden plate

Intermittent Fasting

In today’s modern world, with our constant and on-demand access to food, we rarely go longer than an overnight fast of 8-12 hours. However, the practice of “Intermittent Fasting” is quickly gaining in popularity.

Intermittent fasting is any fasting period lasting less than 2 days, and there are several popular methods:

  • Time-restricted eating: shortens the “eating window” to a certain number of hours per day, thus extending the overnight fast. The most popular time frame is 16/8, which allows an 8-hour eating “window” and 16 hours of fasting daily. Most individuals accomplish this by pushing off or skipping breakfast. Other common time frames include a 12/12 approach or a 14/10 approach.
  • OMAD or “One Meal A Day” (also known as the Warrior Diet) is exactly how it sounds, you eat only one large meal per day. Many individuals do this type of fast just once or twice a week and either eat normally on the other days or layer in a time-restricted eating pattern on subsequent days.  

  • The 5:2 diet: involves eating normally for 5 days out of the week and restricting calories to 500 or less on 2 non-subsequent days out of the week.  

  • Alternate Day fasting: This involves alternating days of eating with days of full fasting or severe caloric restriction (500 calories or less). 

According to a review of the clinical research published in the New England Journal of Medicine in the area of intermittent fasting using both human and animal models, intermittent fasting shows tremendous benefits across a variety of health conditions, including diabetes, obesity, cardiovascular diseases, neurological conditions, and cancer.

Anecdotally, individuals often report decreased hunger and improved energy, less bloating/better digestion, and improved mental clarity. In general, Intermittent fasting is relatively safe for most individuals and easy to implement. 

Intermittent fasting should not be used by individuals who suffer from eating disorders, are underweight, or who are simply unwell or chronically ill. More intense forms of intermittent fasting like OMAD, 5:2, and alternate-day fasting should also be used with caution since low blood sugar or electrolyte imbalance can occur.

wooden fork and spoon on a white plate

Prolonged Fasting

While intermittent fasting can definitely lead to improved weight and metabolism, prolonged fasts lasting longer than 2 days can result in additional health benefits. When we fast beyond 24 hours, our body starts a process called “autophagy” which is essentially like a deep cleaning at the cellular level. This is the stage where pathways are triggered to “clean up” worn-out cells and debris and replace them with new, better-functioning cells.

There are a few different types of prolonged fasts:

  • Water fasting: this involves consuming water only, with no other foods or beverages consumed. Duration can be anywhere from 3-21 days.

  • Dry fasting: this involves consuming no food or water and can be very dangerous. This practice should not be considered unless under direct medical supervision. 

  • Fasting Mimicking Diet: this type of fasting uses a proprietary formulation of special foods “trick” the body into a fasting state while still consuming food. This type of fast allows for the added benefits of prolonged fasting but without many of the challenges that come with other forms of prolonged fasting. 

 Prolonged fasting can have many of the same benefits as intermittent fasting, with the added benefit of cellular autophagy. But it also comes with some additional risks and challenges. The risk of low blood sugar, dehydration, and electrolyte balance is much higher with both water and dry fasting. Prolonged fasting should not be undertaken by individuals with type 1 diabetes, underweight individuals, women who are pregnant or breastfeeding, or individuals with heart conditions or chronic illnesses. In addition, prolonged water-only fasts and dry fasts have a much higher “drop-out” rate due to the challenge of feeling hungry and navigating social schedules that revolve around food. 

FMD fasting kit 

ProLon’s Fasting Mimicking Diet, or FMD for short, helps make fasting easier by providing food throughout the process. The FMD is a 5-day kit made up of foods, supplements, and a special drink that enables your body to get into and remain in a fasting state while still being able to eat what's provided in the kit. Decades of research by Dr. Valter Longo at USC have gone into the development of this fasting kit. To date, there are a total of 16 ongoing clinical trials using ProLon, and 10 published studies. In one randomized, controlled trial using 100 subjects, participants did the 5-day cycle of ProLon, one cycle per month over 3 consecutive months, while resuming a normal diet between rounds of ProLon. These were the results of that study:

  • Participants lost an average of 5.7 pounds, and weight loss was predominantly abdominal fat.
  • Average waist circumference decreased by 1.6 inches. Lean body mass (muscle) was preserved.
  • Average abdominal fat loss was 9.6% in participants with BMI over 25.
  • In participants with a BMI over 30, average weight loss was 9 pounds and weight remained significantly lower even after returning to their normal diet after 3 months. 

Most weight loss methods (like prolonged calorie restriction) cause loss of muscle rather than fat which, over time, decreases metabolism and makes it hard (if not impossible to maintain the loss). ProLon nourishes the body and targets the loss of visceral fat while preserving lean muscle tissue. The foods and drinks also help to give you a sense of fullness and get you into ketosis more quickly and easily. For this reason, most people are able to complete the 5 days without the negative side effects of prolonged fasting like extreme hunger, irritability, and cravings. ProLon can also offer a refreshing mental break from meal planning, preparation, and food shopping since all the food you need to complete the 5 days is provided for you! 

 Everything you need for the entire 5-day fast will be in your kit, no additional food or drink is needed so it couldn't be any easier! And the kit is good for 6 months so no need to worry about timing it exactly right - just head to this link to purchase a fasting kit and save 20%!

variety of healthy food choices

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