< Calculators < Intermittent Fasting Calculator: Find Your Perfect Fasting Schedule

Intermittent Fasting Calculator: Find Your Perfect Fasting Schedule

Melissa Mitri post Reviewer
Melissa Mitri post Reviewer
Verified by Melissa Mitri
MS, Registered Dietitian, Former President of CT Academy of Nutrition & Dietetics

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When on an intermittent fasting (IF) weight-loss plan, it is sometimes hard to understand when and how much to eat, which is why Welltech designed a dedicated calculator to help simplify this process.

If you want to know how fasting can support your weight loss and how this calculator can make your intermittent fasting experience easier, then this is just the article you need to read. 

Intermittent Fasting Calculator

This free intermittent fasting calculator, developed and verified by Welltech experts, enables you to calculate your feeding and fasting windows easily. All you need to do is follow the instructions, press the “Calculate” button, and you will immediately see your eating and fasting window times appear on your calculator screen.

Using an intermittent fasting time calculator can facilitate your weight-loss journey by allowing you to achieve a more organized eating schedule, which is especially useful for those who work set shifts or have a particularly busy agenda.

Calculation Method

The free fasting calculator can provide you with specific feeding and fasting windows through simple calculations.

To obtain your feeding and fasting times, the calculator will first need to know your IF protocol, which is determined by the duration of these two phases. 

The intermittent fasting calculator provides you with some of the most popular fasting protocols, such as the 16/8 or the 18/6, by default, but also offers a custom option where you can input your preferred feeding and fasting time duration manually.  

Once you determine the duration of each phase, the calculator will require you to input what time you would like your feeding window to start.

Using a modulus operator, the fasting calculator will then be able to determine the exact times you should start and stop eating across a 24-hour time span. The results will be displayed on the screen with the chosen time format.

How Does Intermittent Fasting Work?

Intermittent fasting is a dietary protocol characterized by eating phases where you can eat and drink freely, alternated with fasting phases, during which you cannot consume any calories.

Fasting can lead to ketosis, where your body starts pulling energy from your fat stores since it doesn’t have fuel to pull from. This is why IF is an ideal dietary protocol for many people aiming to get rid of excess body fat. [1] [2]

Ketosis also occurs when consuming a very low-carbohydrate diet. If, therefore, you want to maximize your fat-burning potential and achieve results faster, you can combine IF with a ketogenic diet. [3]

Main Types of Intermittent Fasting

Below is a list of some of the most popular IF protocols.

main types of intermittent fasting illustrated, intermittent fasting calculator

14/10 Intermittent Fasting

As the feeding window lasts for 10 hours and allows enough time for three main meals, this IF protocol is particularly suggested for beginners. 

16/8 Intermittent Fasting

This protocol requires 16 hours of fasting and allows food intake for the remaining 8, enabling you to cover at least two of the main meal times. For this reason, this approach is suitable for beginners as well. 

18/6 Intermittent Fasting

18/6 intermittent fasting requires you to fast for 18 hours and allows food intake for the remaining 6 hours. Due to the long fasting window, this protocol is more commonly suggested for people who have already gained some experience with less restrictive intermittent fasting protocols. 

20/4 Intermittent Fasting

The 20/4 intermittent fasting protocol requires you to abstain from food for 20 hours a day, so it is more suitable for advanced fasting practitioners. Due to the short 4-hour feeding window, you’ll want to make your meals as nutritious as possible.

23/1 Intermittent Fasting

The 23/1 IF protocol is mostly suggested to those who already have some experience with fasting. Even then, this protocol shouldn’t be practiced more than once a week. To prevent health concerns and nutritional deficiencies, always consult a nutrition professional when following this protocol. 

24-Hour and Longer Fasts

Fasts that last 24 hours or more are not suitable for beginners due to the high strain they put on the body. This type of fast should not be maintained for a prolonged period and should always be monitored by a health professional. 

24-hour fasts are usually practiced as a part of alternate-day fasting when you fast every other day, or the eat-stop-eat method, when you fast for a day once or twice a week.

Intermittent Fasting Benefits

Intermittent fasting offers a series of benefits. Below, you can find the main ones.

proven benefits of intermittent fasting illustrated, intermittent fasting calculator

Reduced Risk Of Developing Cardiovascular And Chronic Diseases

Fasting may lower biomarkers linked to chronic and cardiovascular disease, such as blood glucose or cholesterol levels. Over time, this decreases the risk of developing any chronic illness associated with these markers, such as type 2 diabetes. [4]

Weight Loss

Intermittent fasting promotes weight loss as it results in lower energy intake and increased use of fat for energy production). [4] 

Reduced Stress

IF decreases oxidative stress and the risk of developing inflammatory health issues associated with it, such as Alzheimer’s disease. [5]

Improved Gut Health

IF is linked to a more favorable gut microbiome, which ultimately results in improved intestinal health. [5]

Risks & Restrictions

However, there are some risks or contraindications linked to intermittent fasting.

All in all, research has demonstrated that appropriately designed IF protocols don’t cause harm to the body. [5] However, side effects can occur when daily calorie intake is too low or fasting windows are too long.

Risks of intermittent fasting:

  • Tiredness and fatigue
  • Constipation
  • Headaches
  • Lightheadedness
  • Nutrient deficiencies
  • Irritability
  • Muscle wasting 

Contraindications for intermittent fasting

You should refrain from fasting if you:

  • Are a child or a teenager
  • Suffered or currently suffer from an eating disorder
  • Are pregnant or breastfeeding
  • Have an immunodeficiency
  • Had traumatic brain injuries
  • Are weak or have low muscle mass

Intermittent Fasting for Weight Loss

Intermittent fasting has been found to be as effective as other calorie-restricted weight-loss protocols to reduce body fat. [6]

With IF, calorie restriction is usually achieved by limiting the amount of time dedicated to eating rather than eliminating certain food groups. This is why many people find IF more flexible than other diets, making it easy to follow for long periods. 

Furthermore, IF has been shown to improve appetite regulation, which can lead to more mindful food choices and increased fat burning. [5]

Other Important Factors to Consider to Lose Weight on Intermittent Fasting

Intermittent fasting can help you lose weight. However, there are a few other things you should take into account if you want to achieve the best results. 

Here are a few tips to follow if you want to maximize fat loss when intermittent fasting.

Calorie Deficit

You must be actively in a calorie deficit to drop fat. So, even if you’re only eating for a few hours a day, you likely won’t lose weight unless your calorie intake is at a level to support weight loss. 

Eat Nourishing Food

Many people who follow an IF protocol eat whatever they fancy. However, it is important to consume a nutrient-dense diet packed with whole foods if you want to support your health while losing weight. 

These foods can also make you feel full for longer, which makes it easier to abstain from eating during your fasting window.

Activity Levels

Increasing your activity levels is essential if you want to increase your calorie expenditure and achieve your fat-loss goal faster. 

Final Words

Intermittent fasting can be a great way to lose weight, and using a calculator to determine your feeding and eating window times can make this process easier. Here are the main key points about intermittent fasting and the dedicated Welltech calculator:

  • Determining your feeding and fasting hours using an IF calculator can support your weight-loss journey. It does this by allowing you to plan a well-organized eating and exercise schedule.
  • Intermittent fasting is a dietary protocol often followed by those who aim to lose weight, characterized by alternating feeding and fasting phases.
  • Intermittent fasting stimulates ketosis and fat oxidation, which further aids weight loss.
  • There are many types of IF protocols with different feeding and fasting durations. Longer feeding windows are more suitable for beginners as they adjust to the process of fasting.
  • Intermittent fasting has several health benefits such as weight loss, reduced risk of developing cardiovascular or chronic illnesses, decreased oxidative stress, and improved gut health.
  • If daily calorie intake is too low or feeding windows last too long, then there is a higher risk of side effects.
  • Some population categories should refrain from intermittent fasting as it may pose a health risk to them.
  • Besides intermittent fasting, you can increase your chances of weight loss by staying in a calorie deficit, favoring nutrient-dense foods, and keeping physical activity levels high.
Disclaimer This Intermittent Fasting Calculator is intended for informational purposes only and does not address individual variations, health conditions, or specific circumstances. It should not be considered a substitute for professional medical advice, diagnosis, or treatment. We strongly recommend consulting with a qualified healthcare professional or a registered dietitian before making any decisions or taking any actions based on results obtained from this Intermittent Fasting Calculator. Use of this Intermittent Fasting Calculator is at your own risk, and any reliance on information and results obtained from it is solely your responsibility.

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