How to Fast: Part 1 — The Different Types of Fast

by BiohackMD Staff May 27, 2019 5 min read

How to Fast: Part 1 — The Different Types of Fast

How to Fast: Part 1 — The Different Types of Fast


So you’ve decided to givefasting a try! You’re on your way to some seriously incrediblehealth benefits, but how do you get started? Which type of fast should you go for? And how do you do it safely?


There are a number of ways to fast, all of which have their own benefits and drawbacks, but the best type of fast for you will depend on factors like your health goals, your lifestyle, and your tolerance for hunger.


Here, I’ve broken down the most popular methods to help you decide, and I’ve provided some advice to help you practice safely.


Water fasting


Water fasting is just as the name suggests — you take in nothing but water. There’s absolutely no food or other liquids allowed for the duration, although some people practice a more flexible approach that allows black coffee or tea.


This is the simplest and most effective way to fast, putting you intoketosis very quickly and allowing you to get maximum benefits from your fast. Ideally, it should last three to five days, but I’d recommend building up to this with shorter fasts as it can be quite a challenge at first.


Bone broth fasting


Similar to a water fast, a bone broth fast involves drinking only bone broth and water.


Bone broth is made by simmering animal bones and vegetables. Until recently, it was mainly used as a base in cooking, but it’s becoming increasingly popular as a drink thanks to its many health benefits. It’s full of collagen, amino acids and trace minerals, and it’s thought to boost gut, joint and immune health, among many other benefits.


Like a water fast, a bone broth fast should ideally last around there to five days. You can drink as much bone broth as you like during this time, which makes it a little more manageable and satisfying than water alone. It’s cheap and easy to make, but you can find it ready-made at most large grocery stores and health stores too.


Fat fasting


A fat fast involves restricting your calorie intake and getting most of those calories from fat. It works on the same principle as theketo diet, where the lack of carbohydrates forces your body to start burning fat for energy instead


If you want to get the benefits ofketosis (particularly the rapid fat loss) without having to endure a restrictive water fast, then a fat fast is a great way to start. If you’re more active than the average person, it’s also a good way to avoid the lethargy that comes with a typical fast.


On a fat fast, you should aim to eat around 1200 calories a day, with around 85% of those calories coming from fat. Choose high-quality, monounsaturated fats like organic coconut oil, grass-fed butter and avocado, and keep carbs to a minimum. If you keep this up for around four days, you can expect to lose around five to eight pounds of water weight and fat.


Exogenous ketone fasting


When your body has exhausted its reserves of glycogen (the stored form of glucose), it starts to burn fat for energy instead. At this point, you’re said to be in a state calledketosis, the state in which the many benefits of fasting occur.


During ketosis, your liver breaks down fat to create chemicals called ketones, which are then used for energy. These naturally produced chemicals are called endogenous ketones, but you can also buy synthetic powder or pill supplements called exogenous ketones.


At the start of a fast, exogenous ketone supplements boost the levels of ketones in your body until you can produce enough of your own. This helps you transition into ketosis much quicker, and it can help to alleviate some of the negative side effects of fasting.


An exogenous ketone fast is essentially a water fast with accelerated benefits. You consume nothing but water, ketones and electrolytes for up to four days, taking the supplements three times a day for the first two days and then twice a day for the next two days. At that point, you should be producing enough ketones by yourself.


How to fast safely


Fasting is a powerful health tool but it should always be practiced carefully. As with any significant change to your diet, you should always talk to your physician first to make sure it’s safe for you. This is particularly important if you have a pre-existing illness or you’re taking medication.


Who should avoid fasting?


If you fall into any of the following groups, you should avoid fasting altogether:


    • Pregnant or breastfeeding moms.
    • Children and young teenagers.
    • People with active infections or diseases.
    • People with a history of eating disorders.


Preparing for a fast


In the lead-up to any longer fast, it’s a good idea to prepare your body by gradually reducing your food intake.


If you’ve never fasted before, or if you have particularly high energy needs, you might experience side effects like blood sugar crashes, lethargy and intense hunger if you jump straight into a longer fast. In this case, I’d recommend starting with shorter fasts and building up to five-day fasts.


During a fast


Electrolytes (sodium, potassium and magnesium) are essential for healthy organ and muscle function. Your electrolyte levels can become dangerously unbalanced during a fast, so it’s important to take electrolyte supplements throughout.


After a fast


If you’re fasting for three days or more, it’s important to reintroduce food carefully. If you go back to eating heavy meals straight away, you can experience a potentially life-threatening condition called re-feeding syndrome.


Break your fast with something light like broth, soup, or soft-cooked vegetables, and steer clearer of heavier foods like dairy, meat or fish. Take it easy on the alcohol and caffeine too!


Exercise and fasting


It’s technically okay to exercise on a fast if you’re feeling well and able. However, if you’re new to fasting, avoid exercise the first few times until you know how it affects your energy and blood sugar levels. And if you feel unwell at any point, stop exercising and rest immediately.


Listening to your body


It’s normal to feel a little weak, nauseous, or dizzy as you get used to fasting, but sometimes discomfort can be a sign that fasting is causing you problems. Listen to your body and if you have any concerns, take them seriously!


If you really can’t tolerate fasting, or you feel genuinely unwell, break your fast gently with a small, light meal. If you experience fainting, vomiting, a racing heartbeat, lasting stomach pain, or any other worrying symptoms, seek medical advice immediately.


Maximize the benefits of your fast


Whichever type of fast you choose, I recommend combining it with aketogenic diet during your eating periods. This is the best way to keep on reaping the many benefits of ketosis, even when you’re not fasting.


BiohackMD Staff
BiohackMD Staff