IF: How To Break A Fast [DON’T Get It Wrong]

  • Author: Kara
  • Date: May 8, 2023
  • Time to Read: 7 min.

In this article, we will take you through the dos and donts of how to break a fast following intermittent fasting. You do not want to undo all of your hard work by getting this wrong, nor do you want to make yourself feel ill post fast. So let’s get into how to break a fast the right way!

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There are a number of different types of intermittent fasting, all of which can be combined with the keto diet for amazing results.

How to break a fast does not really differ depending on what type of fasting you are doing. However, the longer you have been fasting, the more mindful you are going to need to be when breaking your fast.

How To Break A Fast

The Different Types of IF On Keto

There are a number of forms of intermittent fasting (IF). None of these are unique to keto and can be done without combining them with a keto diet.

But seeing as you’re here, I’m guessing that you are interested in combining intermittent fasting with keto and reaping the rewards from this.

Intermittent Fasting

Intermittent fasting is the umbrella term for going for a period of time without eating.

There is an eating window, followed by a feeding window.

People will fast, and feed for different periods of time. Most people will begin with 16/8 fasting. This means you will fast for 16 hours and eat for 8 hours.

People will generally build up for there.

Once they are seasoned faster, they will move on to the other types of fasting, as described below.

  • 16/8
  • 17/7
  • 18/6
  • 19/5
  • 20/4

Generally, if you’re new to intermittent fasting, this is where you will start.

One Meal A Day (OMAD)

OMAD stands for ‘One Meal A Day’, sometimes people will refer to this as one meal per day.

The concept of this is simple, you only eat one meal a day.

Sometime this may be referred to 23/1 fasting. I.e. you fast for 23 hours of the day, and only eat within a one hour period.

For more on OMAD, we have a guide, on what is OMAD on keto.

Alternate Day Fasting

Some people interpret ADF as not eating one day and then eating the next.

We would advocate the 36 hours due to the health benefits that the body starts to see at 36 hours. This means not eating for 36 hours and then eating all of your macros within the following 8 hours.

Some people will ‘alternate’ days like this for a period of weeks or even months.

Fasting for 36 hours brings no end of health benefits.

Check out our guide on alternate date fasting with keto if you want to find out more about this.

Extended Fasting

Extended fasting is an intense form of intermittent fasting.

When extended fasting, people will refrain from eating for a period of 36 up to 72 hours.

Some people will take an extended fast beyond 72 hours, however, we do not discuss fasts of these lengths here.

If you are fasting for longer than 72 hours, this should be supervised by a medical professional.

If you are on any medications or have any health conditions or concerns at all, you should seek advice from a health care professional before beginning a fast.

Health Benefits of Fasting

For more on the health benefits of each type of fasting, check out each of the guides above for specifics.

The general health benefits you can achieve through fasting are;

  • Fat Loss
  • Muscle Definition
  • Rebuild Your Immune System
  • Deeper Ketosis
  • Increased Autophagy
  • Reducing Inflammation
  • Resets Gut Microbiome
  • Mental Clarity
  • Hormonal Balance
  • Insulin and Leptin Rebalance
  • Weight Loss

See our guide to the keto fasting timeline to understand more about the health benefits which are triggered at different points on the fasting timeline.

Also, we are well aware that there are a lot of acronyms and abbreviations that are specific to the world of intermittent fasting, bookmark or print out our keto intermittent fasting key terms guide.

You may also be interested in our keto terms and keto abbreviations guide.

What Happens When You Start Eating After Fasting?

When you have been fasting, your gut has had a break. Rather than spending its time and energy breaking down and digesting food, it has been able to focus on removing toxins from cells as well as allowing time for cell repair.

During this time blood sugar has decreased and depending on the period of your fast, other metabolic processes may have kicked in.

Also, again depending on how long you have been fasting, but your stomach will likely have shrunk in size, meaning it does not need a big meal to fill it again.

Reactivating Your Gut

When you start eating again, your gut is reactivated. Going full out and eating a big heavy meal is likely to put added strain on your gut. It will take time to recognize that it needs to stop ‘repair’ mode and needs to return to digesting mode.

If you overfill your stomach at this time, it is likely to start ‘knotting’, and you may feel some real discomfort. Some people have reported diarrhea too, and let’s face it, none of us want to go through that!

After we have fasted for any period, it is natural to want to eat a lot, as psychologically we feel like we have deprived ourselves and we deserve a treat.

The treat is a big meal.

Also, when you start to eat, your blood sugar will increase, even if you are eating a low-carb, keto diet.

Please be mindful not to eat a high number of carbs, if you are continuing with a keto diet or not. You do not want to see a big spike in blood sugar.

How To Break Your Fast [Safely]

Once your gut has rested due to your period of fasting, you do not want to put too much strain on it. The body has done some amazing things to support you during your fasting period, it’s now your turn to repay the favor.

Warming Up Your Gut

Break your fast by eating an easily digestible, low-carb meal.

If you are following a keto diet, you will likely be familiar with bone broth. This is nutrient-dense, high in fat, low in carb, and high in electrolyte soup/drink.

Drinking a mug of bone broth will be enough to awaken your gut, without putting heavy foods in there that it needs to break down.

Small Meal Time

Your stomach naturally contracts when you’re not eating as much. Depending on how long you have been fasting, your stomach may have contracted a little bit, or a lot. Either way, you do not want to overload it and stretch it.

Your first ‘proper’ meal should be 30 mins to 90 mins have you have reactivated your gut.

Fish and poultry are easier for your stomach to digest than red meats, so it may be worth planning a meal with chicken or fish as the main event, with some easy-to-digest leafy greens.

Don’t make this a big meal. The meal should be able to fit on a side plate (and no, not piled a foot high as if you are at the all you can eat buffet!). 

It is likely that this small meal will fill you up and you can return to your normal keto eating pattern.

At this point listen to what your body (not your mind) is telling you it wants.

Foods To Avoid When Breaking A Fast

Depending on long you have been fasting, will depend on how sensitive your gut will be to receiving food again. As discussed above, some foods are harder for the body to digest than others, even keto foods. So it is best to avoid these until you have warmed up your gut.

Keto foods to consider avoiding until you have warmed up your gut are;

  • Red meats
  • Raw Vegetables
  • Eggs
  • Nuts
  • Dairy
  • Fat heavy foods
  • Alcohol
  • Artificial sugars (even if they are keto-friendly sugars)

I know it’s unusual to not recommend fatty foods to a keto eater, but whilst you are trying to reawaken your gut, try and skip deep-fried foods, oven-baked, or pan-fried chicken thighs are perfect for this, they contain fat, but are not dripping in it!

Moreover, check out our guide for intermittent fasting and alcohol. You should not drink alcohol during your fasting window, or once your fast is complete, you should not break your fast with alcohol.

Top Tips For Breaking A Fast

Bringing all of the above together, we have lined up our top do’s and don’t for breaking a fast.


  • Small initial meal (bone broth or similar is perfect)
  • 30 mins to 90 min, a slightly bigger meal that is nutrient-dense
  • keep up your hydration
  • avoid excessively fatty or fried foods initially
  • avoid foods that are harder to digest
  • avoid artificial sugars
  • do listen to how your body responds to your initial intake of food


  • Break a fast with alcohol
  • eat a big meal before warming up your gut
  • eat foods that are hard to digest
  • don’t eat sugars (including keto-friendly artificial sugars)
  • don’t ignore your body, it will tell you what it wants and when it wants it.

How To Break A Fast Like An Expert

There you have it, you should now know how to break a fast like a pro. In short, start gentle, and build up for there. You should now know what foods to prioritize, and which to avoid initially. Remember your keto principles and you will not go far wrong.

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