The Stages of Intermittent Fasting
January 15, 2023
You may have been hearing the term ‘intermittent fasting’ buzzing around on the health scene recently - and for good reason. It’s a pattern of eating that has been gaining more attention in recent years for its impressive health benefits (1). With its evolution rooted in rich cultural and religious practices, recent science has bolstered its health-boosting-benefits, bringing it to the forefront of the health industry.
Intermittent fasting involves alternating dedicated periods of eating and fasting, consuming only water, tea or black coffee. Intermittent fasting has many different types of schedules, ranging from daily 16-hour fasts to longer fasts of up to 48 hours completed only occasionally.
In this blog post, we’ll take a look at the different stages of intermittent fasting and explore what happens inside your body at each stage of the journey!
How to Do Intermittent Fasting
Intermittent fasting is typically done on a daily or weekly basis, depending on the chosen length of fast. For example, you could fast intentionally for 16 hours every day or do a 24-hour fast once a week. The most common type of intermittent fasting is the 16:8 method, which involves eating during an 8-hour window and fasting for the remaining 16 hours.
Your method of fasting should be chosen based on the following:
- Your body’s unique needs
- Your long and short term goals
- Your lifestyle
When choosing a style of intermittent fasting that works for you, it is important to listen to your body throughout the entire process, adjusting your fasting timer according to your successes and obstacles.
Track your progress throughout your fasting journey is undeniably valuable, ensuring that you are consuming an adequate amount of water, calories and nutrients. This can be recorded with a written diary, or through a tool such as Fastic. After all, our app IS designed specifically for those looking to improve their health and well-being through fasting.
What Happens to Your Body During a Fast?
When you’re fasting, your body goes through several stages. Each stage offers a different benefit; from body fat utilization and insulin management, to cellular healing and a systemic reduction of inflammation.
As the duration of your fast progresses, your body shifts its use of energy from food to fat stores. It then enters a new phase of cellular cleaning, autophagy, where we reap the benefits of extended fast durations, ending with ketosis.
Transitioning through each stage is an impressive feat of biological magic; let’s take a closer look at the ins-and-outs of what your body gets up to during each stage of intermittent fasting.
The Stages of Intermittent Fasting
Phase One: Immediately after your meal
Like a well-oiled machine, your body gets to work right after your meal; ingested carbohydrates are being processed and released into the bloodstream as glucose (sugar). As a result, your blood sugar rises, initiating the production of insulin.
As a hormone, insulin has two important functions:
- It stimulates the absorption of sugar, supplying your tissues with a quick boost of energy
- It stores energy for when your body does not immediately require it, converting glucose into glycogen. Glycogen is stored in your liver and muscles, only to be released when the energy is required, like when exercising vigorously! But if your glycogen stores are full, the excess will be stored in your tissues in the form of body fat.
Phase Two: 3 hours after your meal
Glucose is transported throughout the blood and tissues by insulin, resulting in a drop in blood sugar. Whilst insulin is in circulation, your body is primed to absorb energy. During this time, as long as glucose is in the blood and glycogen is in your muscles and liver, fat is not used as a source of energy. Our body switches to energy production from fat once the glucose in your blood has been depleted and the glycogen reserves are used up.
Phase Three: 9 hours after your meal
After digestion and insulin production has settled, your body has a brief resting period.
However, we’re soon back into action because our organs, muscles and cognitive tissues all require continuous energy - here, we welcome glucagon, a hormone produced in the pancreas that promotes the breakdown of glycogen to glucose in the liver!
As soon as blood sugar levels drop, the body must react. In doing so, glucagon is released back into the bloodstream, settling blood sugar level and supplying energy to the body.
Phase Four: 11 hours after your meal
Your body’s glucagon supplies are now running low. But because your vital organs are always in need of energy, the body switches to fat reserves.
Fastic Fact: The average calorie supply of an adult human in the form of fat reserves amounts to around 80,000 calories.
In order to tap into this energy reservoir, your body starts to produce 6 fat-burning hormones;
- HGH (Human Growth Hormone)
- IGF-1 (Insulin-Like Growth Factor)
- T3 (Triiodothyronine)
This vital hormonal mechanism performs more or less the same function as fat metabolism.
“What is fat metabolism?” we hear you ask?
Fat (lipid) metabolism is a biological process that breaks down any ingested fats into fatty acids and glycerol (the backbone of lipids) into simpler compounds that can be used to aid the cells of the body in everyday functions.
Phase Five: 14-16 hours after your meal
After your fat-metabolizing hormones have set to work in providing the body with new energy, ketones start being produced in the liver as a result of fat burning. While this process starts 14-16 hours after your last meal, it increases in intensity depending on how long you have fasted.
Ketones are fatty acid molecules that are formed when cells are broken down and are known to provide energy to the heart, brain and vital organs.
They activate nerve cells, strengthen intellectual capacity and develop new cells from your stem cells. These little powerhouses are the reason many people report increased levels of focus and cognition when fasting for long periods of time
Phase Six: 16 hours after your meal
You’ve hit autophagy - a process kickstarted by a longer fast and fat-burning!
Translated from ancient Greek αὐτόφαγος (autóphagos), meaning to “consume oneself”, this is exactly what is happening 16 hours after your last meal; your cells begin to process themselves.
Old cell components and unused proteins are recycled during this stage, completely renewing the cells at work! This clean up process increases the efficiency of your cells as well as prolonging their lifespan, and with that, your own.
By this point, your stomach is probably rumbling, excited for your next meal. But wait! Breaking a fast effectively is a vital step to ensuring this lifestyle is sustainable for you, so let’s do this together.
How to Break a Fast
Breaking a fast is just as important as going into it. When you’re breaking a fast, it’s important to ease your body back into eating by slowly introducing nutritious, easily absorbed foods that encourage healthy digestion.
Transitioning into an eating phase with a balanced meal is the key to success. Focus on creating a nourishing and varied plate, including proteins such as lean beef, fish or tofu, healthy fats like avocado and nuts as well as complex carbohydrates like wholegrains. Each macronutrient is essential to health and well-being.
- Protein: The building blocks of your cells, proteins help to build and repair your body every single day. They also help to oxygenate blood cells, create digestive enzymes and even regulate our hormones (2)! It is vital to ingest an adequate amount of protein because our body doesn’t store it as it does with fats or carbohydrates, so aim for 1-1.5 grams of protein per kilo of bodyweight.
- Fats: For fuel and insulation, fats have gotten a bad reputation over recent years in the advertising industry, but they are essential for a healthy body! Healthy fats are vital for hormonal health, brain function and provide protection for our vital organs.
- Saturated: Foods like processed meats and dairy, baked goods and ice cream include saturated fats. While delicious, these fats should be eaten in moderation.
- Unsaturated: Foods such as avocados, nuts, seeds and fish provide us with unsaturated fats that help to lower cholesterol (3).
- Carbohydrates: Foods like whole grains, breads, fruits and vegetables contain carbs, essential for energy storage, digestive fiber and even Serotonin production (4). We recommend you focus on unprocessed complex carbohydrates, and pair them with a source of protein or fat to regulate your blood sugar.
Eating a balance of protein, carbs and healthy fats after having fasted for a long time is essential to satisfy your body’s needs, fuel your energy levels, keep you fuller for longer, and to perform basic bodily functions.
When building your meal, focus on foods that will not spike blood sugar, irritate the gut or leave you craving more. Ensure you take the time to consciously prepare, cook and eat your meal, giving your mind and body time to adjust back into an eating phase and aiding healthy digestion in an unstressed state.
To sum it all up…
Intermittent fasting is a popular nutrition trend that involves alternating periods of eating and fasting. There are different types of intermittent fasting schedules, ranging from daily 16-hour fasts to longer fasts of up to 48 hours. During a fast, your body goes through several stages, from the initial fed state to the long-term fasting state. It’s important to break a fast carefully by slowly introducing nutritious foods to your diet and avoiding overeating.
It is important to use intermittent fasting in a healthy and sustainable way to ensure you’re creating habits that support your mental and physical well-being.
If you’re looking to try intermittent fasting, try Fastic Plus today. Learn from the experts about the benefits of fasting, creating your healthy lifestyle, how to progress in your health goals and be a part of a world-wide community of like-minded individuals.
Haven’t gotten the Fastic app yet? Download it for free on your App Store!