Intermittent Fasting Rules

Intermittent Fasting Rules

Written by Andrew Brewer. ⚕️Reviewed and fact checked by our medical team.

Intermittent Fasting Rules

With the recent increase in interest in intermittent fasting, there can be some confusion on when to fast and when to eat. There are few hard-set rules for intermittent fasting as there are so many different methods, but there are certainly some recommendations you should adhere to.

Intermittent fasting can be a powerful weight-loss tool when done right, so it’s important to understand what your body needs. It provides many different benefits to the body while helping you lose weight. But if done improperly, intermittent fasting can cause some harm to the body.

Here are some of the biggest rules and recommendations for intermittent fasting. To get the most out of the experience, it’s recommended that you stick to these recommendations and take care of your body throughout the process.

We’ll start by looking at the many different intermittent fasting methods. This will help us break down the rules and recommendations associated with intermittent fasting by each method.

Key Takeaways

  • There are many different methods of intermittent fasting, each with its own set of rules and recommendations. It’s important to choose the right method for your body’s needs.
  • When practicing intermittent fasting, it’s essential to stay hydrated, keep busy during fasting periods, and have healthy snacks on hand.
  • Intermittent fasting has many benefits, including weight loss, improved insulin sensitivity, and reduced inflammation. However, it can also have potential risks, such as dehydration, low blood sugar, and nutrient deficiencies.
  • It’s important to space out fasting days and speak with a healthcare provider before starting an intermittent fasting plan to avoid potential risks.
  • Fasting apps can be useful tools to help track progress and stay on track with intermittent fasting.

Different Methods and Different Rules

There are many different ways to intermittent fast. Some are designed to help you lose weight quickly while others are for the more gradual approach. Each method comes with its own pros and cons and should be chosen based on the needs of your body.

With these many different methods of fasting come many different rules and recommendations to follow. Some of the rules are generalized and can apply to each method of intermittent fasting whereas others are specific to one.

Hourly Methods

Many of the rules associated with these intermittent fasting methods can be applied throughout. They’re all relatively similar in practice and therefore come with the same base set of rules for fasters to follow. Here is a quick breakdown of the hourly intermittent fasting rules.

  • 16:8 – This is probably the most common form of intermittent fasting. This method is the practice of eating your daily calories within an 8-hour window and then fasting for the remaining 16. The rules are that you should cut out eating and most forms of drinking once the fasting period begins. Typically, the 16 hours of fasting start around 8 or 9 pm and then ends at noon or 1 pm.
  • 18:6 – This is a very similar method of intermittent fasting to the 16:8, but the window of food intake is slightly smaller. Instead of the 8 hours of eating, you’re limited to 6 hours. This requires you to get all of your meals in within the smaller window before your fasting time starts.
  • 20:4 – Much like the two above, this hourly intermittent fasting window requires you to get all of your meals and calories in within a short period. For this method, you can only eat for 4 hours a day, and then you must fast for the remaining 20.
  • 22:2 – This is the most restrictive hourly intermittent fasting plan recommended by experts. As with the others, this limits you to eating within a 2-hour time frame. The remaining 22 hours of the day are for calorie and fat burning. With an intermittent fasting plan as restrictive as this one, it’s recommended that you don’t do it every day of the week.


This method of fasting is where a user will eat normally for five days of the week and then fast for a full 24-hours. The day of fasting should occur twice a week and should NOT be consecutive. That’s one of the biggest rules of this fasting method – space your fasting days so that your body can recover.


The same rule applies to this method of fasting – space your fasting days apart so that your body doesn’t shut down. In this case, the two days of the week where you eat only 500 calories should have at least one in between them.

Don’t forget to check our 10 best fasting apps to make your intermittent fasting journey easier.


  • What are the different types of intermittent fasting?

There are several types of intermittent fasting, including the 16/8 method, the 5:2 diet, alternate-day fasting, and the eat-stop-eat method.

  • How does the 16/8 method work?

The 16/8 method involves fasting for 16 hours and eating during an 8-hour window each day.

  • What is the 5:2 diet?

The 5:2 diet involves eating normally five days a week and restricting calorie intake to 500-600 calories for two non-consecutive days.

  • What is alternate-day fasting?

Alternate-day fasting involves fasting every other day and eating normally on non-fasting days.

  • How does the eat-stop-eat method work?

The eat-stop-eat method involves fasting for 24 hours once or twice per week.

  • Can I drink water during the fasting period?

Yes, it is important to stay hydrated during the fasting period, so drinking water is allowed.

  • Can I drink coffee or tea during the fasting period?

Yes, black coffee, tea, and other non-caloric beverages are generally allowed during fasting.

  • Is intermittent fasting safe?

Intermittent fasting can be safe for most healthy adults. Still, it may not be appropriate for certain groups, such as pregnant or breastfeeding women, individuals with a history of disordered eating, or those with certain medical conditions. It’s always important to consult a healthcare professional before starting a new diet or exercise program.

Andrew Brewer

Andrew Brewer

Andrew Brewer started to give people the guidance that he never received when he was first starting. His goal is to make your goals achievable and to offer you only the best fasting apps that the internet has to offer. You're not on your own - Andrew and the entire family of reviewers at are here with you every step of the way!