What Breaks An Intermittent Fast And What Doesn’t

The Internet’s full of inconsistent answers to the question, ‘What breaks a fast during intermittent fasting?’ Let’s clear this up for you and then explain what else you should know too.

What breaks an intermittent fast? Anything you consume that contains calories will break an intermittent fast immediately, this is because whatever raises your body’s insulin level will alter your fasted state and technically break the fast, even if it only contains a very small number of calories.

Confusion occurs because people don’t fully understand the concept of intermittent fasting (sometimes shortened to the letters IF) in enough detail, they may also want to sell something to help intermittent fasting, make it sound easier and less structured, or sometimes they may want to make things sound more complicated than they are too.

The concept of intermittent fasting has to be understood properly to figure out the food or drink items that break it. Once you’re clear about the concept, you can easily identify what breaks the intermittent fasting cycle you’re on.


In simple terms, intermittent fasting is alternating the times of the day, or cycles, when you eat and when you don’t, so are fasting. And the times you eat or fast vary depending on the intermittent fasting plan or model you decide to follow.

Whatever the intermittent fasting method is, the core objective is to make the body and its metabolic system respond in a controlled and deliberate way – basically biohack it.


What are the benefits of Intermittent Fasting? It has three main health and fitness benefits – fat loss, turning waste material in cells into energy and reducing calorie consumption.

The first is fat loss as fasting boosts fat loss. Without getting scientific it turns up your cell’s and your hormone’s ability to burn fat, this makes your body more efficient and more lilely to choose this as an energy source not only when exercising but in day-to-day life too.

The second reason is what’s called Autophagy; this is the ability of cells to turn waste material and old protein in to energy – more on this later.

And the third is simply that when people cut out eating during certain times of the day it generally tends to make them reduce their consumption of food and therefore calories. No more late night snacking or starting the day with a meal.


  • 16/8
  • 14/10
  • 24 Hour Fasting
  • 20/4 (also called Warrior Diet)
  • 23/1 (also called One Meal A Day Diet or OMAD)
  • 36 Hour Fasting
  • 48 Hour Fasting
  • Extended Fasting (normally 3 to 7 days)
  • Alternate Day Fasting
  • Juice Fasting
  • Fat Fasting
  • Dry Fasting
  • 5:2 Diet
  • ProLon Fasting Mimicking Diet
  • Protein-Sparing Modified Fasting (PSMF)

To explain the basic principle behind fasting, let’s use the most common intermittent fasting cycle is the 16/8 method.

This 16/8 method simply means you will only eat within an 8-hour window, and fast during the rest, 16 hours. For example you may eat between 12 midday and 8pm and not eat from 8pm to 12 midday the following day.


The popular belief is that the body would lose weight due to fasting and that is an overriding good thing. Well, it is true that intermittent fasting can help you to get rid of the extra fat you’ve gathered over the years, but this is not the sole purpose by any means.

Intermittent fasting does three things to the human body – in a nutshell: Hormesis, Ketosis and Autophagy.

Don’t worry if this sounds like a foreign language, I’ll explain.


Hormesis triggers protective metabolic pathways to increase mitochondrial density. This way the immune system of the body gets better. In the long run, it makes the body’s organisms much stronger. In human terms, you will not fall prey to diseases as easily or often.


Ketosis is the process of elevating ketone substances in the bloodstream. Due to ketosis, the body burns fat to fuel bodily functions. It’s a good way to get rid of unwanted fatty tissues too – this is why you’ll hear people talking excitedly about a keto diet.


Autophagy turns the body’s old waste products and protein into energy and recycles the body waste through self-digestion – basically your stronger cells combine with those that are not as strong and this as all sorts of benefits.

But a word of warning, there are many positives with intermittent fasting, but that doesn’t mean fasting as much as you can it the right thing to do, you can have too much of a good thing as they say, so have a plan that works for your body and your lifestyle.



If you’re not consuming any calories for more than 12 hours, that would be considered a fasted state. And if you’re having food or drink without calories, that’s fine too – so feel free to drink as much water as you like, especially biohacked water.

There’s an opinion shared by many that if you consume something with less than 50 calories your body will remain in a fasted state, so if you want a black coffee or tea you can, especially after you wake up, but you’re not being 100% true to the fast.

But in reality, most people use intermittent fasting for metabolic, autophagy and fat loss effects, not just to fast, and drinking coffee, in particular, has shown to help this even when you’re not in a fasted state.

There are several ways you can measure what you are burning in the body as fuel, even when you think you are in a fasted state, so it’s not guesswork, I use what’s called a Lumen, a device that you breathe through to measure this.

It’s impossible to start listing every single food or drink that contains a calorie here, use something like MyFitnessPal to help with that.

So to help you let’s focus on “grey areas” that people are confused about. This list highlights food, drinks, and supplements that some believe are safe during an intermittent fast, but here’s the truth…


All kinds of solid food items break your intermittent fast.


There are some so called negative calorie foods that are given the benefit of doubt during the fasted state. But you should refrain from eating any solid food if you want your fasting to be precise.

  • Apple: Apples are often considered as a ‘zero calorie’ fruit. While it is true that Apples contain a lot of water and fiber, that doesn’t mean it doesn’t contain any calories. An average apple has 52 calories per 100 grams. Add 0.2 g fat with that too.
  • Apricot: Apricots may have many health benefits, but they’re not calorie free. Having 48 calories per 100 grams, an average apricot might make it a better option than an apple, but not the perfect one by any means.
  • Beetroot: Beetroot is used as a juice item, but it’s not for intermittent fasting. It does have 0 saturated fat, but along with this there are 43 calories per 100 grams. Also, it’s not a pleasant experience to eat raw beetroot for most people.
  • Celery: With just 16 calories per 100 grams, celery is an incredible healthy option. But still, a calorie’s a calorie.
  • Cucumber: So many people eat cucumber during their intermittent fasting cycle, but that doesn’t make it calorie free. Cucumbers have about 15 calories per 100 grams.
  • Soft Drinks / Sodas: Soft drinks contain high amounts of sugar; hence they are not going to keep your intermittent fasting intact. Diet soda can be sugar-free, but you should still avoid it, as it is not always totally calorie free, and that’s before you think about the other negative factors diet drinks have.
  • Fruit Juices: Even if you make your fruit juices at home without adding any sugar, fruits do have calories and juices would contain that. Moreover, most of the fruits tend to be high in natural sugar.
  • Almond Milk: Sugar free almond milk is a very good addition to a healthy diet, but not for perfect intermittent fasting. It contains both fat and protein, in small amounts.
  • Lemon Tea: If you like tea, then stick to regular sugar-free tea and don’t add lemon into it. Some people do drink tea with one or two drops of lemon during their fast, but lemon isn’t totally calorie free.
  • Bulletproof Coffee: I have no idea why some even recommend drinking bulletproof coffee during an intermittent fast, with things like MCT Oil in it there are normally about 100 calories in a cup. So you shouldn’t even go near bulletproof coffee during your fast. Its purpose is to replace breakfast and provide other health benefits, not keep you in a fasted state.
  • Protein Shakes: Don’t have a protein shake during your fasted state, as it will affect insulin.
  • BCCA: BCCA supplements are very insulinogenic (stimulating the production of insulin) – it’s part of reason people take them, so don’t even consider them if you’re fasting.
  • Collagen: Collagen’s positive impacts on burning fat are quite well known, but the glycine it has will definitely break your fast. And if you are looking for autophagy, then avoid collagen at any cost.
  • Sweeteners: This is dependent on the specific sweetener – if it has calories as some do, then it will break a fast.


So now you know that anything that increases your insulin levels breaks a fast. But your intermittent fast doesn’t have to be too strict, complicated, or stressful to be beneficial.

Depending on your goals it may be okay to consume a minimum amount of calories during your fast, as long as it doesn’t mess with the overall objective.

And the best advice, when it comes to intermittent fasting, is this – know why you’re fasting and then plan what approach is best for you’re health and fitness goals and your lifestyle, this way you know what you’re doing, not doing and when because success in this like anything is based on just three things:

  1. Stop doing what’s not beneficial.
  2. Do more of what is beneficial.
  3. Try new things that have a high probability of being beneficial to see if they are for you.

So, if you’ve not done so already, try intermittent fasting and some of the other biohacking approaches to becoming substantially fitter, healthier and happier.

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