Intermittent Fasting: Benefits, How-to & Risks

Intermittent fasting (IF) is a popular eating pattern that alternates between periods of fasting and eating. It has garnered attention for its potential health benefits and flexibility in accommodating various lifestyles.

There are several intermittent fasting methods, such as the time-restricted 16/8 and 14/10 methods, where you fast for 16 or 14 hours, respectively, and eat during an 8 or 10-hour window. 

The key to success lies in finding the method that works best for you and aligns with your personal goals and daily routine.

This guide will provide essential information on intermittent fasting, helping you understand the basics, the benefits, the various methods, and tips for incorporating it into your lifestyle. 

What Is Intermittent Fasting (IF)?

Intermittent fasting (IF) is an eating pattern that focuses on when you eat rather than what you eat. This approach offers a flexible, sustainable lifestyle change rather than a restrictive diet.

Research indicates that IF can help manage weight, prevent certain diseases, and even reverse some health issues. 

However, it’s essential to consult a healthcare professional before starting intermittent fasting, especially if you have any pre-existing medical conditions.

Intermittent Fasting Methods

There are several IF methods, each with its own fasting duration and frequency. Regardless of the method, the principle remains the same, which is incorporating periods of fasting with periods of eating. 

Alternate-Day Fasting

In alternate-day fasting, practitioners alternate between fasting for 24 hours and eating without restrictions for another 24 hours. 

This method can be quite extreme for beginners, as it involves total abstention from food every other day. However, it is known to speed up weight loss and improve markers of health significantly. 

Seek medical advice before beginning an Alternate-Day Fasting regimen to ensure it is safe for your specific needs.


Eat-stop-eat is a flexible method requiring a 24-hour fast once or twice weekly. The 12-hour fast involves fasting for 12 hours each day and consuming meals within a 12-hour window.

During fasting days, one abstains from eating, but can consume calorie-free beverages.

The 16/8 Method

The 16/8 method involves fasting for 16 hours daily and restricting your eating window to 8 hours. Often, this simply extends the fasting period during sleep, meaning most people only skip breakfast.

Adopting the 16/8 method can promote weight loss, improve metabolic health, and simplify one’s lifestyle. However, it’s important to eat healthy foods during the eating period.

The 5:2 Diet

With the 5:2 diet, you consume your regular calorie intake for five days and reduce it to about 25% of normal on the remaining two days. This method is more of a dietary pattern than a fast. 

It is beneficial for those who find daily fasting too difficult. 

However, it’s crucial to ensure the reduced-calorie days are still balanced and nutritious.

How IF Affects Your Cells and Hormones

When you practice intermittent fasting, your body undergoes various hormonal and cellular changes, such as a change in your insulin levels and cellular repair processes.


Intermittent fasting has notable effects on insulin, the hormone that regulates blood sugar levels. Fasting periods help to lower insulin levels in the bloodstream, enabling efficient fat burning.

Additionally, intermittent fasting can improve insulin sensitivity. This may be highly beneficial for people who are pre-diabetic or dealing with insulin resistance, but it’s always essential to consult with a healthcare professional first.


Intermittent fasting influences ketone levels in the body. During fasting periods, insulin levels fall, and the body starts to break down fat for energy, leading to the production of ketones.

Elevated ketone levels in the body can improve brain function and mood and potentially reduce the risk of chronic diseases like Alzheimer’s. Still, it’s necessary to monitor ketone levels to avoid entering a state of ketoacidosis, particularly if you have diabetes.


Intermittent fasting can lead to a significant increase in levels of hormones that can play an essential role in growth, body composition, cell repair, and metabolism.

Additionally, an increase in hormones during fasting periods can boosts muscle growth, promotes fat loss, and offers an array of other health benefits.

Cellular Repair

Intermittent fasting triggers a cellular repair process called autophagy. During this process, cells break down and metabolize broken and dysfunctional proteins that build up inside cells over time.

Enhanced autophagy from intermittent fasting could provide protection against several diseases, including cancer and Alzheimer’s disease. Notably, the balance of this process is crucial, and thus, professional guidance is advised.

Stress Hormones

Two stress hormones, epinephrine and its nor- variation, experience fluctuations during fasting. While short-term increases in these hormones help mobilize fat stores for energy, it’s crucial not to overdo fasting to maintain hormonal balance. 

Observing your body’s responses and seeking professional advice in case of emotional distress is advisable.

Benefits of Intermittent Fasting

Intermittent Fasting boasts several benefits ranging from weight loss to improved metabolic health. It can boost cognitive function, enhance longevity, reduce inflammation, and lower the risk of chronic diseases like diabetes and heart disease.

However, these benefits can vary among individuals.

Improves Metabolic Health and Blood Sugar Control

By regulating insulin levels and reducing insulin resistance, it can help manage blood sugar, an essential factor in metabolic syndrome and type 2 diabetes prevention.

Having a faster metabolism can also aid in weight loss, as it means your body burns calories more quickly than usual. This often results in higher energy expenditure, even at rest, which can lead to a deficit in calorie intake versus output. This deficit often results in weight loss.

Improves Cognitive Function

The increase in ketone levels during fasting provides additional energy to the brain, improving focus and mental clarity, thus improving cognitive function.

In addition, intermittent fasting could potentially reduce the risk of neurodegenerative diseases like Alzheimer’s and Parkinson’s. However, more research is needed to understand these cognitive benefits fully.

Reduces Inflammation

Intermittent Fasting may help reduce inflammation, a key driver of many chronic diseases. By preventing the release of pro-inflammatory cells called monocytes in your blood, it can help lower inflammation levels.

However, the extent of these benefits can vary from person to person, which is why a healthcare professional’s advice is valuable to ensure fasting regimes align safely and beneficially with different health profiles.

Lowers Risk of Cardiovascular Diseases

Intermittent Fasting can contribute to a healthier heart. By improving factors like blood pressure, cholesterol levels, triglycerides, and inflammatory markers, it can potentially lower the risk of cardiovascular disease.

However, individual outcomes may vary, and it’s essential to pair fasting with a balanced, heart-healthy diet as well.

Increases Lifespan

Intermittent Fasting could potentially contribute to increased longevity. Animal studies show that fasting can extend lifespan akin to calorie restriction.

Moreover, by improving many health markers and reducing the risk of several chronic diseases, intermittent fasting could lead to a longer life. Do note, however, that more research is needed involving human participants to firmly establish this benefit.

Makes Your Healthy Lifestyle Simpler

Intermittent Fasting can simplify your healthy lifestyle. With fewer meals to plan, you save time and effort in meal preparation. A consistent eating pattern aids in better nutrient absorption and supports your training goals.

Developing healthy habits becomes easier when you focus on fewer meals.

Who Should Avoid Intermittent Fasting?

While intermittent fasting offers various health benefits, it’s not suitable for everyone. Certain populations should exercise caution or avoid this dietary approach altogether.


People with diabetes, particularly type 1, should be cautious about intermittent fasting. Uncontrolled blood sugar levels during the fasting period can lead to serious health consequences.

Moreover, for people treating diabetes with insulin or oral medication, improper adjustment of doses could lead to dangerously low blood sugar levels. It’s crucial to consult with a healthcare provider before starting any fasting regimen.

Experiencing Fatigue

If you frequently experience fatigue or have conditions like anemia, you should exercise caution around intermittent fasting. Extended periods without food can exacerbate fatigue and lead to decreased energy levels.

Moreover, fasting could potentially cause lightheadedness, especially in those already prone to fatigue.

Eating Disorders

Intermittent Fasting can be challenging if you have a history of eating disorders. For some, restrictions around eating times can trigger unhealthy behaviors and exacerbate the condition.

Health should always be the priority, and any dietary change that may promote a harmful relationship with food should be avoided. Professional dietary and psychological advice should always be sought in such cases.

Safety and Side Effects

Introducing intermittent fasting into your routine can be beneficial. However, it is essential to be aware of potential side effects and safety concerns.

Remember, intermittent fasting is not a one-size-fits-all approach. Customize your fasting plan to fit your unique lifestyle and health needs.


One of the most common side effects of intermittent fasting is increased hunger. This is especially likely during the initial adaptation phase as your body adjusts to the new eating schedule.

However, this hunger often subsides after a few days or weeks. If persistent hunger occurs, it may be an indication that this approach to eating is not suitable for you.

Fatigue and Nausea

During the initial stages of intermittent fasting, you might experience symptoms of fatigue and nausea. 

These symptoms can result from the body’s adjustment to a new eating cycle and decreased calorie intake. Such symptoms usually reduce over time as the body adapts.

Frequently Asked Questions

What is the ideal fasting window for weight loss?

The ideal fasting window for weight loss varies for each individual. Generally, a 16:8 fasting schedule is popular, where you fast for 16 hours and eat within an 8-hour window. 

However, some people prefer shorter fasting periods like 14:10 or longer ones like 18:6. It’s essential to find a schedule that works best for your lifestyle and goals.

How does intermittent fasting impact health?

Intermittent Fasting has numerous health benefits. Some studies show that it can improve insulin sensitivity, reduce inflammation, and promote cellular repair. Additionally, it may help with weight loss and improve heart health.

However, it is not suitable for everyone, and individuals with certain health conditions should consult a healthcare professional before starting intermittent fasting.

How should a beginner start intermittent fasting?

Beginners should start by gradually introducing fasting into their daily routine. One approach is to extend your overnight fast by a few hours and slowly work your way up to a 16-hour fast. 

Another option is to start with the 5:2 method, incorporating two days of reduced calorie intake. It’s essential to listen to your body and consult with a healthcare professional if necessary.

Can intermittent fasting help lose belly fat?

Yes, intermittent fasting can help with losing belly fat. When your body enters a fasting state, it relies on stored fat, including abdominal fat, for energy.

Intermittent fasting combined with a healthy diet and regular exercise can be an effective strategy to target belly fat and improve overall health.