Healthy Diet

The Science Behind Intermittent Fasting: How It Affects Your Body

During the last years, intermittent fasting has gained a significant amount of popularity as a dietary pattern that involves alternating eating and fasting phases. This post aims to provide information and guidance on intermittent fasting and its impacts on the human body and health

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The Science Behind Intermittent Fasting: How It Affects Your Body

How intermittent fasting works

Intermittent fasting is based on the concept of limiting the time frame of the patient’s caloric consumption.

This can be achieved using various techniques, such as the 16/8 method with 16 hours of fasting, the 5:2 method by eating normally for five days and limiting calories to 500-600 on the other two non-consecutive days, and a fasting every other day method, for example.

All of them eventually reduce the number of meals consumed and the patient’s energy intake.

Hormonal changes during intermittent fasting

This way of eating causes various changes in the body’s hormones. Insulin levels drop, helping regulate blood sugar and triggering the body to burn fat. The growth hormone increases after consuming it.

Hormonal changes during intermittent fasting

Intermittent fasting affects levels of hunger hormones such as leptin and ghrelin, reducing hunger in the process. It has other effects on hormones, including cortisol and testosterone.

Effects on metabolism and weight loss

Fat burning is increased, and the body produces ketones, which it uses for energy. Metabolic rate and energy breakdown increase, making it easier to lose weight. However, intermittent fasting is unique in that it protects lean mass during weight loss – muscle.

This is critical to maintaining health and body composition. Ultimately, it may also improve insulin sensitivity, which reduces the chance of developing type 2 diabetes.

Intermittent fasting’s influence on brain function and well-being is profound. It increases the production of a protein known as brain-derived neurotrophic factor, which promotes the creation and maintenance of neurons.

As a result, it increases neuroplasticity and neurogenesis, allowing you to learn and remember more. Additionally, it possesses anti-inflammatory and antioxidant.

Potential health benefits of intermittent fasting

Intermittent fasting has been found to help control blood sugar and lower the risk of type 2 diabetes. In addition, it is important to maintain cholesterol and blood pressure levels, which has a positive impact on heart health.

Inflammation can be reduced and the immune system can be supported through fasting. Likewise, recent research has proved that it may prevent chronic diseases that are related to the age factor such as cancer, and Alzheimer’s.

Considerations and potential side effects

Approaching intermittent fasting should be personalized, and it may need to be discussed with a healthcare provider. Individuals with certain medical conditions or dietary requirements should not attempt it.

Some of the challenges one may face during the fasting period include irritability caused by hunger. However, some people should avoid it, such as pregnant women. The following are some ideas and plans for intermittent fasting.

Pregnant woman should not perform an intermittent fasting
Credit @gabrielaespinalphotography

Staying hydrated and listening to hunger cues is also essential. Regular physical activity must also be included in the intermittent fasting lifestyle.

What are the different methods or schedules of intermittent fasting that people follow?

Time-restricted feeding

Another common way of intermittent fasting is time-restricted feeding (TRF). In this case, a person reduces their daily diet to a certain number of hours. For instance, 16/8 means abstaining from food for 16 hours and eating in the remaining 8 hours.

As a result, the person skips breakfast and eats three meals during the 8 hours. There is another version, called the 18/6 method, which implies an 18-hour fast and 6-hour meal. By shortening the time to eat, TRF also reduces the opportunity to snack and eat late. Thus, it controls calorie intake and weight.

Alternate-day fasting

Another method of intermittent fasting is alternate-day fasting. With this method, the individual takes the daily allowance on one day and fasts the next day.

The caloric restriction day can be partial, where an individual may have 500 cal or less. The following day they can have normal caloric intake without restriction. This method is effective for weight loss as it creates a considerable caloric deficit.

5:2 diet

The 5:2 diet is one of the most reputed types of intermittent fasting. It requires followers to eat normally for five days within a week and consume a low amount of calories during two other non-consecutive days.

Time-restricted feeding

During fasting days, men can consume 600 calories, while women are only allowed to eat 500. The other five days should have no restriction on one’s ration but be balanced and healthy.


Here are some additional methods or schedules that people may follow when practicing intermittent fasting:

1. Eat-stop-eat: This method involves one or two complete 24-hour fasts per week, where no food is consumed.

2. Warrior Diet: This approach involves fasting during the day and having one large meal at night within a 4-hour eating window.

3. Spontaneous meal skipping: Some individuals may choose to skip meals spontaneously without following a specific schedule.

4. OMAD (One Meal A Day): As the name implies, this method involves consuming all daily calories within a single meal, usually lasting for around one hour.

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Other mechanisms contributing to weight loss during intermittent fasting

Growth Hormone Increase

Firstly, the levels of growth hormones also increase. Growth hormone declines in line with growth hormone-releasing hormone secretion as glucose and insulin levels rise in the body. They assist in the maintenance of muscle mass while ensuring the burning of fats, all of which are weight loss aid.

Higher Level Of Insulin Sensitivity

Secondly, there is a higher level of insulin sensitivity. People with insulin resistance have a harder time losing weight because their bodies will save extra glucose as fat rather than burn it for energy.

Improved Autophagy

Thirdly, there will be improved autophagy. Autophagy recycles damaged cells and removes fat cells that have not been adequately programmed.

Apart from these mechanisms, IF could also lead to better appetite management, lessen inflammation, and enhance gut microbiota and metabolic gas, making them fantastic weight aids.

Improved Insulin Sensitivity

Intermittent fasting helps your body respond adequately to blood sugar regulation, which is known as insulin sensitivity.

In intermittent fasting, insulin sensitivity can drop significantly. People with type 2 diabetes can experience improvements in insulin resistance levels. When you fast, your body uses glycogen as its primary source of fat.

Start Slowly and Gradually Increase Fasting Duration

Listen to Your Body

For beginners who are new to intermittent fasting, it is important to start slowly and gradually increase the fasting duration. This allows your body to adjust to the changes and minimizes the potential side effects. Begin by skipping one meal or extending the time between meals by a few hours.

intermittent fasting for weight loss
Credit @micahpastrami

Do note how your body responds through the fasting hours. In case you feel unwell or experience lightheadedness or other forms of discomfort, you might want to consider shortening the fasting window.

Should the symptoms persist, contact a healthcare practitioner as soon as feasible. With time, an individual can fast longer.

As an example, some folks refuse up to two meals daily. Another option is to increase the hours of fasting to more than 16.

Nonetheless, as previously stated, it is critical not to push too hard. Since everyone’s circumstances are unique, those who choose to give fasting a try must conduct a personal study.

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Stay Hydrated During Fasting Periods

Importance of Water Intake

When practicing intermittent fasting, it is essential to stay hydrated throughout the fasting periods. Drinking an adequate amount of water helps prevent dehydration and supports various bodily functions.

Aim to drink at least 8-10 glasses of water per day, even when you are not eating during your fasts. You can also consume herbal teas or infusions without adding any sweeteners or calories as they can help curb hunger pangs and provide additional hydration.

Choose Nutrient-Dense Foods During Eating Windows

Focusing on Balanced Meals

During the eating windows in intermittent fasting, it will be essential for novices to eat nutrient-packed food that supplies all essential vitamins, minerals, and macronutrients.

This will guarantee that your body is well-maintained in optimal health. Nutrient foods include varieties of fruits, vegetables, whole grains, lean meat, and healthy fats.

Alternatively, avoid relying on processed foods and taking sugary snacks since they may cause low energy and don’t make any progress. Therefore you must have a meal plan for your eating time, including a variety of food groups.

Seek Professional Guidance

Consulting with a Healthcare Professional or Nutritionist

I encourage beginners in the above statement to refer to the appropriate professional. Following that, you should receive professional guidance in considering this diet.

Credit @abhishek_4_numbari

A healthcare professional or nutritionist could give you advice that is tailored to your unique health needs and objectives. They can help determine if it is permitted for you based on any underlying medical conditions or medications you are taking.

Additionally, professional assistance may address any concerns or anxieties you may have and follow up with you consistently to confirm you are following this diet.


Intermittent fasting is a type of dietary plan that includes continued periods of eating and non-eating without necessarily excluding specific food intake.

Unlike traditional fasting, the method emphasizes the timing of eating rather than the food to consume. One of the benefits of intermittent fasting is its indirect contribution to improving a person’s metabolism and overall well-being.

Some of the methods of implementation include the 16/8 method and the alternate-day fasting. However, the ways may differ from individual to individual because the results may not necessarily be identical.

Some of the associated risks include irritability, hunger, and poor management of the fast. People can slowly switch to the method and listen to their bodies to start adequate intermittent fasting.

While the results could be visible only after some time, what matters most is consistency. It can also be used in combination with certain diets or exercise types.

Additionally, it affects the energy and cognitive function levels positively. People have to drink sufficient water and be careful with food or drinks that will break the fast when fasting.

Hence, some foods have a high performance regarding insulin and blood sugar regulation. The other advantage is related to decreasing the inflammation in bodies.

Many studies and surveys could be considered in this regard, showing the benefits of intermittent fasting regarding weight loss, metabolic state, and lifespan. Nonetheless, there are plenty of myths that need to be debunked as well.

List of common misconceptions of Intermittent fasting

  • It causes muscle loss
  • It slows down metabolism
  • It leads to nutrient deficiencies
  • It is only effective for weight loss
  • It is not suitable for women
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FAQ (Frequently Asked Questions)

Q: What is intermittent fasting?
A: Intermittent fasting is a dietary pattern that involves cycling between periods of eating and fasting. It is usually done to promote weight loss and improve overall health.

Q: How often should I do intermittent fasting?
A: It depends on your goals, but most people will fast between 16-24 hours a day, usually done several times a week.

Q: What are some benefits of intermittent fasting?
A: Intermittent fasting can help improve weight loss, reduce inflammation, and improve overall health. It can also help reduce risk factors for certain diseases, such as type 2 diabetes and heart disease.

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