The HOW and WHY Behind Intermittent Fasting

Intermittent fasting is a pattern of eating - not a diet - where you eat in a certain time window and fast for the remaining time. This pattern does not change what you eat (healthy foods encouraged), only WHEN you eat, thus not making it just another diet. Intermittent fasting is a way to lose weight and become lean, without losing muscle mass.

Fasting dates back to almost 460 BC during the time of Hippocrates, the father of modern medicine. He once said, “To eat when you are sick, is to feed your illness.” Fasting has been a method of not only weight loss, but also to improve cognition, energy, longevity, Alzheimer’s and insulin resistance prevention, and even reverse the aging process altogether. It has also been a major component in many religions and cultures for spiritual reasons as a way of cleansing and purification. Humans have been fasting for a long time to improve their overall health which makes it a valid type of eating, not just another fad diet.

How does it work?

Fasting can work in a number of ways and can fit how your lifestyle is set up. The typical intermittent fasting works like this: eat during an 8 hour period and fast for 16 hours. For example, eat from 12p-8p and fast from 8p-12p the next day. However, these hours can be moved around depending on work, workouts, etc. Eat from 7a-3p and fast 3p-7a; or eat 2p-10p and fast 10-2p. Fasting can be incorporated into anyone’s life, it is just a matter of finding those best times to do so.

What are the health benefits of this?

When you are eating, insulin is released to convert the sugars in food to use them as energy or to store them in muscle, fat, and liver cells as glycogen (stored sugar/glucose) to be used as energy later on when needed. When food is consumed, your blood sugar rises, triggering the pancreas to release insulin into the bloodstream to convert the sugar into energy or store it as explained before. So when you are eating every few hours, or overeating, it stimulates a major insulin release into the bloodstream which has major long-term damage. However, to understand this, we must dive into the fed state/eating and fasting state first.

In the fed state, our bodies are digesting and absorbing food. This begins when you start eating and lasts for 3-5 hours after. During this time, our bodies do not burn fat cells efficiently because our insulin levels are high due to the food we are eating. When insulin is constantly released due to eating more often, it leads to insulin resistance. Insulin is an important hormone in converting sugar into energy and storing it, but also a bad hormone that can lead to storing more fat from excess sugar/intake of food. After this state, the body goes into a post-absorptive state lasting from 8-12 hours and leads into the fasting state. During this time, it is much easier for our bodies to burn fat cells/use them for energy because the insulin is not in the way to prevent this. This is what leads to fat loss, and the quickest way possible without doing harm to the body.


Intermittent fasting has numerous benefits ranging from insulin resistance to simplicity. When we are not eating as much, insulin is not burning much energy in the process of trying to convert sugar into energy or storing it. We put a lot of pressure on insulin by eating often, which can lead to insulin resistance as mentioned before. Since our bodies only have a certain amount of glycogen we can store(no more than 500 grams which provides 90 minutes of endurance exercise), when those stores are full, the insulin has to take it and store it as fat, leading to weight gain. By fasting, our bodies are not calling on insulin to constantly do work by converting and storing, but instead leaning on those fat cells for energy, thus resulting in weight loss.

Intermittent fasting makes our lives simpler. We do not always have to worry about making breakfast the first thing we wake up in the morning or when your three meals will be and what. In the mornings, you can grab a glass of water or coffee and be on time to work. Intermittent fasting requires less planning and more enjoying your life.

Intermittent fasting can be beneficial for anyone. Whether you want to lose weight, try and fix a disease or illness, or live a life of simplicity, fasting can be incorporated into anyone’s life. Before starting, please refer to your primary doctor or nutrition expert. 

Written by: Matthew Schreder, Program Director for Health & Wellness at the Tri-City YMCA


Nutrition, Food

All opinions expressed here are those of their authors and/or contributors and not of their employer.
Any questions or concerns regarding the content found here may be sent to