Fasting 3/17/2021

What is Intermittent Fasting?

What is Intermittent Fasting?

This course will help you understand what intermittent fasting is and how it can help you improve your health and lose weight.

31 Cards

Fasting is an ancient practice. It involves going without any calories for a period of time. People have been fasting for religious and healing reasons for centuries.

Hippocrates, the Father of Western Medicine, regularly prescribed fasting as a treatment for better health. American inventor and statesman Benjamin Franklin also fasted in his time!

Modern researchers have discovered that fasting for just 12 to 24 hours at a time can help with weight loss and health. They call this intermittent fasting, or IF.

Intermittent fasting is a pattern of eating that gives your body a multi-hour or multi-day break from the work of metabolizing food.

In the next few cards, you will learn what happens in your body when you fast.

Swipe to learn more!

IF involves going for short periods of time without consuming any calories. A calorie is a unit of energy that your body can get from food.

After a meal, fats and sugars like glucose move from your stomach to your intestines, into your bloodstream and then into cells.

Your cells use those fats and sugars to create energy to do their work. But your cells don’t use all these nutrients all at once.

Your body stores extra sugars and fats from each of your meals
in your liver, in your muscles and in your fat tissue.

So what happens when you fast?

First, your body starts to use sugars it stored away after your last meal, like the glycogen in your liver.

But when your sugar stores start running low, after about 12 hours, your body has to turn to other sources of energy.  For example, fasting burns your stored fat!

Your body’s fat-burning mode is called ketosis because when your body is breaking down stored fat for energy, some fat compounds are used by your liver to make ketones.

Ketones are an important source of energy for your energy-hungry brain cells when you are fasting.

While your brain prefers to use sugar for energy, it can use ketones too.

Ketones have many other health benefits.  They help your body to fight stress and they can improve your cognition and memory!

You might be thinking, “I’m ready to get started!”  Take it slow, starting with short 10 to 12-hour fasting windows.

IF can take a little getting used to.

Before your body goes into ketosis and burns stored fat for energy, it sets off alarm bells.

These alarm bells make your stomach growl.  Your empty stomach makes ghrelin, a hunger hormone that tells your brain to find and eat food.

But if you eat every time you feel a little hungry, your body will constantly be breaking down food for energy.  It will rarely dip into your stored fat.  It won’t make many ketones.

When your body senses sugar entering your bloodstream from your gut, it makes insulin.  This hormone tells your cells to stockpile sugar and store energy as fat!

Instead, if you wait until you are moderately hungry to eat your meals, you allow your insulin levels to come down.
A little hungry?  This is prime fat-burning time!

IF allows your body to regularly dip into its fat stores for energy. This can help you lose weight.

Now you know that fasting can help you burn fat.  But when you fast overnight or longer, other good things happen.

Swipe to learn more!

After just 16 to 24 hours of fasting, your cells go into an “eco” clean-up mode called autophagy.

Your cells get busy recycling old proteins and making their cellular components fresh.

Autophagy has all sorts of health benefits.  It helps to protect your brain from neurodegenerative diseases and lowers inflammation.

Fasting is similar to exercise in how it benefits your health.  Both activate autophagy!  Both stress your body out just enough to make it renew and rebuild itself.

Your body even creates extra stress-busting antioxidants when you fast and when you exercise.

Now you know how IF can improve your health and help you lose weight. 

But how do I get started?

Swipe to learn more!

There are many different ways to practice intermittent fasting.

Find a consistent fasting and eating pattern that works best for you.

Are you new to fasting? Try fasting just 12 hours overnight, drinking only water after dinner and black coffee or tea in the morning before you break your fast.

Other popular approaches to IF are the 16:8 (daily fasting for 16 hours, with an 8-hour eating window) and alternate day fasting (fasting every other day).

Celebrate National
Fasting February with us!

Track your fasting in the LIFE Extend app this February.


Fasting for more than 12 hours at a time helps your body to burn fat, make brain-healthy ketones, clean up harmful chemicals and recycle old components.

Fasting for 36 hours or less is generally safe, but you should talk to a physician beforehand.  You should not practice fasting if you are pregnant or breast-feeding, if you have type 1 diabetes, or if you have an eating disorder.
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