19/5 and 16/8 Intermittent Fasting: The Ultimate Guide

19-5 and 16-8 Intermittent Fasting

Intermittent fasting has become a focal point of the health and wellness conversation in recent years, with various fasting schedules gaining popularity. 

Among the most prominent approaches are the 19/5 and 16/8 intermittent fasting methods. 

The main difference between 19/5 and 16/8 intermittent fasting schedules are the window at which you fast and eat.

In this comprehensive guide, I will take you on a journey through the world of intermittent fasting. 

We will explore together what intermittent fasting truly is, delve into the intricate details of 19/5 and 16/8 fasting windows, and discuss benefits and drawbacks to help you decide which intermittent fasting regimen might be the optimal choice for your unique needs and goals.

I will also discuss some additional IF options to consider.

Let’s dive right in.

What Is Intermittent Fasting?

Intermittent fasting is often misconstrued as just another diet plan, but it stands apart as a nuanced approach to when you consume your calories rather than focusing on what you eat. 

It’s fundamentally a lifestyle that revolves around cycling between periods of eating and fasting. 

Intermittent fasting is not a one size fits all strategy. Instead, intermittent fasting works by encompassing various methods, each characterized by specific fasting and eating windows. 


These methods include the popular 19/5 and 16/8 intermittent fasting schedules, among others. 

What Intermittent fasting is not is a magic diet tool. It is simply an eating schedule that works wonders for many people by helping them maintain a set schedule of calorie consumption.

An intermittent fasting plan can help you lose weight by being more calorie conscious and scheduling the periods at which you eat, getting you into a routine.

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What is 19/5 Intermittent Fasting?

19/5 is just one of the many types of intermittent fasting. 19/5 intermittent fasting consists of a 5 hour eating window, and a 19 hour fasting window where you do not consume calories.

The Fasting Window: 19 Hours of Abstinence

In the world of intermittent fasting, 19/5 is a rigorously structured regimen. It entails fasting for 19 hours each day and reserving a 5 hour window for eating. 

The discipline required for this method is certainly not for the faint of heart and may not be for everyone.

But what precisely occurs during these extended fasting periods? When you abstain from food for such a protracted duration, several physiological processes come into play. 

Understanding these mechanisms can shed light on the benefits and drawbacks of 19/5 intermittent fasting.

What You Can Consume During The Fasting Window

During the fasting window of intermittent fasting, you are expected to abstain from consuming calories through food intake, which means avoiding traditional food and beverages that contain calories. 

However, it’s essential to stay hydrated, so drinking water, herbal tea, or black coffee (without added sugar or cream) is generally permitted and encouraged. 

These non-caloric beverages can help curb hunger and keep you hydrated while adhering to your fasting schedule. 

Remember that the primary goal during the fasting window is to allow your body to enter a fasting state through calorie restriction, so you do not want to consume any calories during this time.

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The Eating Window: What Foods Should You Consume?

Being that intermittent fasting is only a pattern of eating and not a magic tool, there are really no rules when it comes to what you can consume.

However, if you are looking to shed body fat and maintain overall health, it is important to maintain a calorie deficit while also consuming adequate amounts of lean protein, healthy fats, and moderate amounts of carbohydrates.

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Protein is so important for maintaining muscle mass when losing weight, so be sure to try and consume 0.8-1.0 gram of protein per pound of body weight.

Benefits of 19/5 Intermittent Fasting

Intermittent fasting may be a great way to schedule your eating periods, but it actually can provide many benefits to the human body.

Improves Insulin Resistance

At the core of 19/5 intermittent fasting’s appeal is its capacity to enhance insulin sensitivity

This means that your body becomes more proficient at regulating blood sugar levels, potentially reducing the risk of developing type 2 diabetes.

To grasp the significance of this benefit, it’s essential to delve into the role of insulin in our bodies. 

Insulin is a hormone that facilitates the uptake of glucose into our cells, ensuring they receive the energy they need to function optimally. 

However, when we consistently consume high levels of carbohydrates and sugars, our bodies can become resistant to the effects of insulin, leading to elevated blood sugar levels which can lead to type 2 diabetes.

19/5 intermittent fasting, by reducing the frequency and magnitude of insulin spikes, helps recalibrate the body’s response to this vital hormone. 

As a result, it can mitigate insulin resistance and contribute to better metabolic health and insulin levels.

Improves Cardiovascular Health

Beyond its effects on insulin resistance, 19/5 intermittent fasting has garnered attention for its potential cardiovascular benefits. 

Heart disease remains a leading global health concern, with factors such as high blood pressure and elevated cholesterol levels contributing to its prevalence.

Research suggests that fasting can be a valuable tool in mitigating these risk factors. 

Extended fasting periods allow the body to engage in processes like autophagy, wherein it clears out damaged cells and supports the growth of new ones. 

This cellular housekeeping extends to the heart, potentially reducing the risk of heart disease.

Moreover, fasting can positively influence blood pressure. High blood pressure, or hypertension, is a well known risk factor for heart disease and stroke. 

There is also research IF can help to mitigate heart failure.

By regulating hormones like insulin and norepinephrine, fasting may help lower blood pressure, enhancing overall cardiovascular health.

Improved Weight Loss

Intermittent fasting may help you lose weight in an easier way by reducing the number of calories you eat in a day, and fewer calories means better adherence to a calorie deficit.

For most people, the window at which they will be fasting is during the time when they are already sleeping. 

They will not need to worry about eating breakfast and will not eat until later in the noon/afternoon time period, which can help decrease the overall amount of calories consumed.

This is only true if you do not overindulge during your eating window. So be sure to be calorie conscious when not fasting.

Weight loss in itself will lead to improved cardiovascular health, decreased waist circumference preventing diabetes, and a healthy body weight overall to prevent many types of diseases.

Increased Cellular Repair

The body induces important cellular repair processes, such as removing waste material from cells.

When we fast, the cells in the body initiate a cellular “waste removal” process called autophagy.

This involves our cells breaking down and metabolizing proteins that build up inside our cells.

Increased autophagy can prevent certain diseases, including cancer and Alzheimer’s disease.

Improved Brain Health

The autophagy we just talked about? That can help your brain as well.

This cellular housekeeping may help reduce the buildup of toxic proteins and ultimately enhance cognitive function over time.

May Help Prevent Chronic Diseases

Intermittent fasting has shown promise in reducing the risk of chronic diseases such as type 2 diabetes, heart disease, and certain cancers. 

By improving insulin sensitivity, regulating blood sugar levels, increasing cellular repair, and reducing inflammation, IF can contribute to better long-term health outcomes, making it a valuable strategy in disease prevention.

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Cons of 19/5 Intermittent Fasting

While 19/5 intermittent fasting offers a plethora of advantages, it’s vital to recognize the challenges and limitations it presents. 

As with any dietary or lifestyle change, what works for one person may not suit another. Here are some cons to consider:

Hunger and Irritability

Extended fasting periods can trigger hunger pangs and mood swings, making it challenging for some individuals to adhere to this regimen. 

This may mean you need to decrease the amount of time you are fasting by trying a different approach.

Difficulty Meeting Nutritional Needs

With a restricted eating window, it can be challenging to consume all the necessary nutrients your body requires for optimal health. 

You may need to plan meals meticulously to ensure adequate nutrition.

Not Suitable for Everyone

19/5 intermittent fasting may not be appropriate for pregnant or breastfeeding women, individuals with certain medical conditions such as diabetes, or those taking specific medications. 

Consulting with a healthcare professional is crucial before embarking on such a strict fasting schedule.

Now, let’s shift our focus to 16/8 intermittent fasting, exploring its nuances and how it compares to the 19/5 approach.

What is 16/8 Intermittent Fasting?

In the realm of intermittent fasting, 16/8 offers a more forgiving approach. It consists of fasting for 16 hours and allotting an 8-hour window for calorie intake. 

This method is less stringent in terms of fasting duration compared to 19/5, making it a more attainable option for many individuals.

Stay with us as we delve deeper into the differences between these two popular fasting schedules and explore why 16/8 may be the preferable choice for some.

Difference Between 19/5 and 16/8

The primary divergence between 19/5 and 16/8 intermittent fasting lies in the duration of the fasting window. In 19/5, you undergo a more prolonged fasting period of 19 hours, followed by a 5-hour eating window. 

In contrast, 16/8 offers a slightly wider eating window, allowing you to fast for 16 hours of the day and eat during an 8-hour period.

But what does this difference in fasting duration mean for your body and overall fasting experience? To answer this question, we must explore the physiological responses and practical implications of both methods.

Why 16/8 May be The Better Option

All Intermittent fasting schedules are not for everyone. Many might feel that 19/5 is too hard to maintain and may opt to try 16/8 instead.

Flexibility: The Key Advantage

The allure of 16/8 intermittent fasting lies in its flexibility. It strikes a balance between fasting and eating that makes it more sustainable for many individuals. 

Unlike the more rigid 19/5 schedule, 16/8 can be more easily integrated into daily life and social activities.

This flexibility can be particularly appealing for those new to intermittent fasting. It offers room for adjustment and allows you to tailor the fasting window to your lifestyle and preferences.

Easier Adherence

Consistency is a crucial factor in the success of any dietary or lifestyle change. 

The less restrictive fasting window in 16/8 may be more conducive to adherence, making it easier to establish a consistent fasting routine.

Things To Consider Before Starting 19/5 or 16/8 Intermittent Fasting

Before taking the plunge into the world of intermittent fasting, it’s essential to consider various factors to ensure it aligns with your health, goals, and daily life. 

Consult a Healthcare Professional

If you have underlying medical conditions, are taking medications, or have specific health concerns, consulting with a healthcare professional is paramount. 

They can provide personalized guidance and ensure that intermittent fasting is safe and suitable for your individual circumstances. Intermittent fasting is not recommended for pregnant women.

Personal Lifestyle

Evaluate your daily routine, work commitments, and social activities to determine which fasting method harmonizes better with your lifestyle.

Nutritional Needs

Consider whether you can adequately meet your nutritional requirements within the chosen eating window. Paying attention to nutrient-dense foods is crucial.

Listen to Your Body

Intermittent fasting should not be a source of physical or emotional distress. Pay close attention to your body’s signals, adjust your fasting schedule as needed, and prioritize your overall well-being.

Additional Intermittent Fasting Options

While 19/5 and 16/8 intermittent fasting methods have gained prominence, it’s worth noting that there are alternative intermittent fasting schedules that offer greater flexibility and might be more suitable for certain individuals. 

Some popular alternatives include the 14/10 or 12/12 schedules. These options provide more balanced fasting and eating periods, which can be a better fit for those who find longer fasting periods challenging.

Let’s discuss some additional popular IF schedules, shall we?

Alternate-Day Fasting (ADF)

  • What it is: Alternate Day Fasting, as the name suggests, involves alternating between days of regular eating and fast days or consuming very few calories.
  • Fasting Days: On fasting days, individuals typically restrict calorie intake to around 500-600 calories, often through a single meal.
  • Eating Days: On eating days, you can consume your regular diet without specific restrictions, such as the next day.
  • Benefits: ADF has also been associated with weight loss, improved insulin sensitivity, and reductions in markers of inflammation. It can also simplify meal planning, as you have days with no dietary constraints.
  • Challenges: It can be challenging to adhere to strict fasting on alternate days, leading to potential hunger and irritability. Some individuals may find it difficult to maintain social commitments around fasting days.

5:2 Intermittent Fasting

  • What it is: The 5:2 method involves five days of regular eating and two non-consecutive days of fasting each week.
  • Fasting Days: On fasting days, calorie intake is usually limited to about 500-600 calories.
  • Eating Days: On the remaining five days, you can eat your usual diet.
  • Benefits: 5:2 fasting may lead to weight loss, improve insulin sensitivity, and support overall metabolic health. It provides flexibility in choosing fasting days.
  • Challenges: Similar to ADF, strict fasting days can be difficult for some individuals. Planning fasting days around work and social commitments can be tricky.

Warrior Diet

  • What it is: The Warrior Diet entails fasting for a substantial portion of the day and consuming all your daily calories within a specific eating window.
  • Fasting Period: Typically, you fast for 20 hours each day, leaving a 4-hour eating window in the evening.
  • Eating Window: During the eating window, you can have one or more meals, with an emphasis on nutrient-dense foods.
  • Benefits: The Warrior Diet can promote fat loss, improve insulin sensitivity, and may align well with evening social activities.
  • Challenges: Fasting for 20 hours can be challenging for some individuals, potentially leading to increased hunger and overeating during the eating window.

These alternative forms of intermittent fasting offer flexibility and may suit different lifestyles and preferences. 

However, it’s crucial to choose the method that aligns best with your individual needs, as adherence and sustainability are key factors in the success of any fasting regimen. 

Consulting with a healthcare professional before starting any fasting routine is also advisable, especially if you have underlying health conditions.

All intermittent fasting schedules are not for everyone.


Intermittent fasting, whether practiced through the 19/5 or 16/8 schedules, holds the potential to yield numerous health benefits, including improved insulin sensitivity and enhanced cardiovascular health. 

However, the decision between these two methods should hinge on your individual preferences, daily routines, and health objectives.

Before embarking on an intermittent fasting journey, always consult a healthcare professional to ensure that it aligns with your health goals and specific needs. 

It’s important to remember that the most effective fasting schedule is one you can consistently maintain over time, while prioritizing your overall health and well-being.