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Fasting may be a growing trend, but most of us don’t know that fasting has been followed for years and even plays a crucial role in many religions and cultures.
Fasting is generally defined as abstinence from food and drinks for a certain period of time, mostly 24 to 72 hours.
The different stages of fasting come with numerous health benefits such as weight loss, improved brain function, better cardiovascular health, and so much more.
1. Different Types of Fasting
1.1. Water Fasting
It involves drinking only water for a certain amount of time.
1.2. Juice Fasting
Involves drinking only vegetable or fruit juice for a specific amount of time.
1.3. Partial Fasting
entails eating only certain types of foods. Certain foods and drinks like meat and animal products, caffeine, and processed food are avoided from the diet for a specific amount of time.
1.4. Intermittent Fasting
In this type of fasting, food intake is completely or partially restricted for a few hours, and a normal diet is followed on other days.
1.5. Calorie Limit
Calories are restricted on some days of the week.
There are many subcategories under these types, such as alternate-day fasting – which entails eating on alternative days or eating only a few hours a day. The stages of fasting may differ depending on what type of fast is being followed by individuals.
2. Five Stages of Fasting
During the process of fasting, our body goes through different stages of fasting.
2.1. Fed State
The first one among the different stages of fasting is the fed state, which usually occurs just a few hours after eating. It usually happens 0 to 3 hours after eating when our body is still undergoing ingestion and storing food.
The body breaks down carbohydrates, proteins, amino acids, and fats; metabolizes them, and stores them for energy for later use.
During this stage, our blood sugar levels rise, and a high amount of insulin is secreted. The amount of insulin secreted depends on the whole meal composition; the higher the carbs in your food, the more glucose in your bloodstream, which means a rise in insulin levels.
During this period, the levels of hormones, namely ghrelin and leptin, also fluctuate. Ghrelin is the hormone responsible for stimulating hunger, whose levels gradually decrease after eating. While leptin does the opposite by suppressing hunger, its levels rise after a meal signalling the brain that your stomach is full.
The major factors that determine how long our body will stay in this state are the size and composition Fed stage, which occurs 0 to 3 hours after the meal, is also called the growth period since our body can burn the available nutrients, build them or even store them.
2.2. Early Fasting Stage
The second one is the early fasting state. This state occurs 3 to 4 hours after eating and usually lasts for about 18 hours.
In this stage, our blood sugar level and insulin levels start to fall, eventually causing the body to convert glycogen1 into glucose to use as energy. By the end of this stage, the body tends to run out of liver glycogen stores and starts to search for alternative energy sources.
Our body then switches from glucose to ketones, but it is important to remember that glucose is still our body’s primary and preferred fuel source.
This leads to more intensification of lipolysis, where triglycerides 2present in fat cells are broken down into molecules of smaller size, which are then used as alternative soulful sources the amino acids, which are considered the building blocks of our body and are also converted into energy.
2.3. Fasting Stage
The next one among the different stages of fasting is the fasting stage, which lasts for about 18 hours to 2 days of fasting.
By this stage, the glycogen levels in the body are completely depleted, and our body instead starts to break down fat stores and proteins, thereby resulting in more production of ketones, a compound that is produced when fat is converted into fuel in our body.
At this stage, our body transitions into the ketosis stage – which is a state where fat is used as the main source of energy by our body, but the transition into this stage does not occur immediately, but only later on.
The major factors that determine when the body enters the ketosis 3state are the size and composition of the meal, the time of the last meal, and so much more. Some common signs of ketosis are loss of weight, tiredness or fatigue, bad breath, and higher ketone bodies in urine, blood, and breath.
Apart from fasting, ketosis can be attained by many other methods. Also, one among them is following a ketogenic diet which is all about lowering the body’s carb intake.
It is also important to note that ketosis cannot be attained while following the popular trend of intermittent fasting as their fasting duration is shorter and ranges from about 12 to 18 hours only. Ketosis requires fasting for not less than 24 hours unless you are on a ketogenic diet.
2.4. Starvation Stage
The starvation state is the fourth stage. It usually occurs about 48 hours after our food intake and is also termed a long-term fasting state by some people.
In this stage, the insulin levels of the body decline, and the levels of BHB – beta-hydroxybutyrate, a kind of ketone body, rise. The increase of BHB levels in individuals varies accordingly, but normally fasting for about 24-72 hours leads to rising between 0.5 to 2mM in our bodies.
At this point, our kidneys also start generating sugar through a process called glucogenesis, thereby serving as the primary source of fuel for our brain as our brain needs a little bit of glucose to function. However, the rest of our body relies mostly on ketone bodies.
2.5. Prolonged Fasting Stage
The prolonged Fasting Stage is the last of all the stages of fasting. By this time, the insulin and glucose levels are low, there is also a suppression of hunger, and the body is now in the state of nutritional ketosis.
During this period, BHB levels 4also steadily rise during fasting. They are most likely to reach around 1.5-3mM levels as the body now generates enough ketones to fuel our body.
Fasting for a minimum of 72 hours decreases the circulation of insulin and glucose by 30% or even more, which can significantly contribute towards cutting down the risk of metabolic diseases. It also comes with other benefits like better immunity, inflammation, and improved metabolic health 5overall.
3. How To Break A Fast?
A person can break a fast in many ways. Some of the recommended ways through which a person can break their fast are:
- Water: By drinking water case, was also included in the fast.
- Small meal: Eating a small meal as eating a large meal to break the fast can drain the digestive system
- Cooked foods: Instead of eating raw vegetables, it is better to opt for cooked vegetables to break a fast
- No New Foods: It is important to not indulge in experimentation as going for new foods to break a fast can make the digestion process harder and even make the person sick in some cases. Therefore, it is always best to stick to foods that our body had tolerated well previously.
4. Fasting: Things to Keep In Mind
Even though fasting comes with a long list of health benefits, it may not be ideal for everyone.
It could be dangerous for people with pre-existing medical conditions. If you have diabetes or have low blood sugar levels, fasting can lead to spiking and crashing of blood sugar levels, posing problems. It is best to consult with a doctor for such people with medical conditions before getting into fasting.
Moreover, for underweight people, fasting is not generally recommended in both adults and adolescents.
Another important thing to make sure of while you are fasting is to minimize physical activity and get enough rest.
4.1. Some of the People for Whom Fasting Can Pose Risks Include
- Pregnant and breastfeeding women
- Diabetic people
- People with medical conditions that require them to eat food
- Children and adolescents
- People with eating disorders
5. Conclusion
The practice of fasting comes with a long list of health benefits such as weight loss, improved heart health, blood sugar control, better brain function, and so much more.
Incorporating fasting into our lives along with a healthy diet and lifestyle can keep many diseases at bay. There are also many different types of fasting to suit every individual’s lifestyle.
The body which undergoes the different stages of fasting is dependent on many factors, as mentioned above.
The most important thing to note while fasting is that in case of any previous medical condition, it is best to consult with a medical professional before really getting into the process of fasting.
5. Frequently Asked Questions
5.1. How Long Should You Do Fasting?
You should at least try to fast for 20 to 24 hours a day
5.2. Is Fasting Good for the Body?
Fasting may provide several health benefits, including weight loss, improved blood sugar control, and decreased inflammation. It might also offer protection against certain conditions like cancer and neurodegenerative disorders
5.3. How Many Hours Is Safe for Fasting?
Studies have found that people who regularly fast more than 16 or 18 hours a day have a higher risk of gallstones.
- Vigh-Larsen, Jeppe F., et al. “Muscle glycogen metabolism and high-intensity exercise performance: a narrative review.” Sports Medicine 51.9 (2021): 1855-1874. ↩︎
- Laufs, Ulrich, et al. “Clinical review on triglycerides.” European heart journal 41.1 (2020): 99-109c. ↩︎
- Zhang, Guanshi, and Burim N. Ametaj. “Ketosis an old story under a new approach.” Dairy 1.1 (2020): 5. ↩︎
- Chaput, C., and M. A. Sirard. “Embryonic response to high beta-hydroxybutyrate (BHB) levels in postpartum dairy cows.” Domestic animal endocrinology 72 (2020): 106431. ↩︎
- Fan, Yong, and Oluf Pedersen. “Gut microbiota in human metabolic health and disease.” Nature Reviews Microbiology 19.1 (2021): 55-71. ↩︎
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