“I fast for greater physical and mental efficiency.”
Intermittent fasting involves voluntary abstinence from food and select beverages for a predetermined period of time. Fasting is not the same as starvation. Fasting is voluntary, informed and controlled; meanwhile, starvation is involuntary, unpredictable and uncontrolled abstinence from food due to lack of availability. Starvation is generally more prorogued and is associated with negative health outcomes.
Fasting, is a very powerful ancient tool which is associated with many health benefits.
Like most things in life, when it comes to food, moderation is key.
Our brothers and sisters currently living in third world countries suffer from nutritional deficiencies due to scarcity of food supply.
Meanwhile, in first world countries obesity is a growing epidemic due to the surplus of food accessibility and availability.
Neither of these two extremes are desirable or healthy.
Intermittent fasting is one easy and effective way to avoid the consequences of excessive food consumption while still enjoying the highly palatable and nutritious food that is available to us.
Think back to our hunter-gatherer ancestors. Every once in a while the hunters would slaughter a buffalo or deer, allowing the family to feast for several days. Once the meat ran out, the hunters would head back into the woods in search of new pray. Acquiring food arguably was one of their most important and demanding tasks. If being in a fasted state impaired their ability to obtain this valuable resource, we likely wouldn’t be here today.
The gatherers would collect seasonal wild plants. They also successfully gathered in a fasted state. Gathering was difficult during the cold months which led to longer fasting periods. If their bodies couldn’t successfully rely on their stored fat from their high carb summer feed, we also likely wouldn’t be here today.
Today, we no longer need to fast because food is always abundant in our grocery stores. Yet, we wonder why we don’t have brain clarity like our ancestors did, why we feel sleepy after every meal and why the numbers on the scale are gradually creeping up.
Fasting is incorporated in every religion and the science is also finally catching up; when done correctly fasting has many health benefits.
How does Intermittent Fasting work?
Intermittent fasting allows for our overworked digestive system and gut microbiome to take a break. Food digestion and absorption requires significant amounts of energy. Giving the body a break from this demanding task is very important. Fasting enables the digestive tract to focus on restoring and repairing.
Additionally, fasting is very beneficial for your endocrine system (hormones). Insulin is our main building and storing hormone. It is released in response to glucose consumption because it facilitates the transfer of blood glucose into the fat cells for storage. On a standard American diet, carbohydrates are consumed at every meal. This triggers repeated insulin elevations throughout the day. Eventually the fat cells become full and stop readily responding to insulin. Higher levels of the hormone are required to achieve the same response. This condition is called insulin resistance. Insulin resistance is linked to many chronic diseases including heart disease, Alzheimer’s, diabetes and PCOS(4). Intermittent fasting breaks this cycle of constant insulin spiking and allows for the body restore its sensitivity to insulin, decreasing the risk for disease. Insulin’s antagonistic hormone glucagon begins to dominate during a fasted state. Glucagon stimulates the breakdown of stored fat leading to weight loss.
The graphs on the right illustrate a typical insulin and glucose response to a Standard American Diet (SAD) and intermittent fasting in a healthy individual.
On a SAD there are much more fluctuations in glucose and insulin levels. The body is less sensitive to insulin and higher levels of insulin are required to bring blood glucose to baseline values. These high insulin spikes often overshoot, leading to post meal glucose dips which trigger hunger. Eventually, even with the increased insulin (hyperinsulinemia) the body is still unable to sufficiently decrease blood glucose. This is known as type 2 diabetes.
With intermittent fasting, both glucose and insulin remain at baseline for two thirds of the day. This helps maintain insulin sensitivity and a rapid and effective response to insulin when glucose is consumed.
Is Intermittent Fasting Safe?
Fasting is a very powerful tool which can be used to prevent and combat disease. But, as with any weapon, if used incorrectly it can become harmful. Ideally, fasting should be done under the guidance of an informed healthcare provider. Working with an educated practitioner will help ensure your success and prevent harm.
Well monitored and controlled fasts are generally very safe and are associated with very few side effects. As a general rule, fasts that are short in duration are safer than extended fasts.
What can be consumed during the fast?
A true fast involves abstaining from all caloric intake. Consuming anything with caloric value would classify as breaking the fast. This means all food and most beverages including juice, milk and pop are off limits. Beverages free of calories and artificial sweeteners are encouraged. This includes water and black or herbal tea and coffee. Most supplements can also be taken during the fast.
Some modified fasts, may not fully restrict caloric intake. Though some research suggests that these modified fasts may be beneficial for health, it is important to recognize that these are not true fasts. Examples of a modified fast may include daily caloric restriction and carbohydrate avoidance during fasting period.
Basic Intermittent Fasting Protocols
There are many different intermittent fasting protocols.
Protocol selection and modifications should be done on an individual basis with feasibility, health goals, lifestyle and personal preferences in mind.
On the left, is a quick summary of the most commonly used true intermittent fasting schedules and modifications.