by Health By Principle

Fasting Do’s and Don'ts


By Rachel Welch  

Does 2023 feel fast to any of you so far? It has felt like a complete blur to me, and I am stunned that we are already so close to the end of January!  


Hopefully you feel great about your resolutions and new years’ goals and their progress. If you set big goals for yourself this year, you’re not alone! Fifty-nine percent of young adults (ages 18-34) and 38% of adults in other age brackets set New Year’s resolutions every year. Among these, close to 50% of goal-setters choose goals related to getting more exercise or movement.  


Health-related resolutions cover the top 3, and a Swiss study found that over 70% of resolutions in their sample centered on improving physical health. With a new health trend at every turn these days, it can be challenging to know which one is the right one for you: from diet, to exercise, to mindfulness, there are many options. 

The practice of fasting is one in particular that has come into mainstream popularity. Before we dive in, I want you to please remember to always consult your doctor before beginning any new health regimen. Fasting can have some serious implications for people with certain health conditions, so play it safe and make sure it’s right for you! Now, let’s go over what fasting is, what you need to know, and some of the main fasting dos, and fasting don’ts. 


History of Fasting 


Fasting is the practice of abstaining from food or drink for a certain timeframe. Fasting, while recently trending as a health practice, is by no means a new thing. It has been a common practice for various groups since at least the 5th century, and Hippocrates was one of the early physicians to suggest it as a form of treatment. He recommended fasting from food or drink to help patients overcome certain types of illness. This partly came about from the doctors’ observation of ill patients’ loss of appetite, or what some called a “fasting instinct.”  


As time went by, medical fasting evolved into official scientific studies on animals and humans.  


Another way that fasting has been used over the years is in the context of religion and spirituality. Fasting and religion have gone hand-in-hand for some time, with beliefs that it would help prepare a person to approach their deities, give them clearer dreams and visions, or help them to make amends after a confession.  


In some Native American cultures, fasting was used as part of a vision quest. Other groups used to fast as part of structured, religious ceremonies. In India, Hindy holy men fast to gain honor and accolades from their peers. In western religions like Judaism, Christianity, and Islam, fasting may be done as a ritual to honor certain days of the year, certain celebrations, or days of mourning. Even politically, fasting has been used by well-known figures like Gandhi, as a means of enacting social change.  


Fasting over the years has achieved different goals for different people, but most recently it has been touted in the mainstream culture to lose weight, balance hormones, improve blood sugar, and even possibly safeguard against cancer and cognitive decline. Here are some of the basics that fasting will typically involve: 



Fasting 101 


Timeframe: most fasts will last 1-3 days (24-72 hours). There is also a variety of fasting known as intermittent fasting, where a person cycles through periods of fasting over the course of a few days. Common structures for intermittent fasting involve eating within an 8-hour window, and fasting for 16 hours, or pretty much any other split that works for the individual and their schedule. 


What’s Allowed: Fasts vary with what a person does or does not consume.  For instance, there are water fasts, where the person only drinks water throughout their fasting duration. On the flip side, there is also dry fasting, where not even water is allowed. Other forms allow the consumption of things like green tea or black coffee, but not food.  


Pros and Cons 


With any health trend, there are good things and not-so-good things, not to mention the factors that will be completely different from person to person! Here are some things to know and consider before deciding if you want to try fasting.  


You Will Be Hungry 

This may come as a no brainer, but it’s something important to consider! Some of us do better at handling our hunger than others. (Talking to you, “hangry” friends). If hunger is something that will significantly disrupt your day, your ability to focus, or your mood, then perhaps fasting is not the best health bandwagon for you! I can guarantee that your family and coworkers don’t want to be snapped at as a result of your new health kick.  


Headaches Might Get Worse 


A lot of us suffer from migraines and understand the correlation between hunger (or lack of proper nutrition) and an increase of migraine symptoms. While migraines and headaches are separate entities, headaches are a common side effect of fasting. They will typically occur during the first few days of a fast, so if you make it past day 3 with no issues, you might be fine! But, fasting shouldn’t cause you immense discomfort, and if it does, it’s probably not right for you. These headaches can also come about as a result of withdrawal from your otherwise routine caffeine.  


Your Stomach Might Act Weird 


When the body that is used to getting meals on a regular basis suddenly doesn’t anymore, it can make some weird things happen to the GI system. Fasting can sometimes lead to issues like diarrhea, nausea, bloating, and constipation. Dehydration is also a risk if the fast excludes all food and drink, and this is obviously amplified if you have these digestive issues that cause your body to lose its liquid faster than normal.  


You Might Lose Energy 


While fasting can ultimately lead to an increase in energy when practiced regularly, you are likely to experience fatigue and lethargy the first few times. This is often due to low blood sugar, which is the direct result of abstaining from food that normally would keep it balanced. For this reason, it is not recommended that people with diabetes engage in fasting.   


To Fast, or Not to Fast 


Now that you can make an informed decision about whether to fast or not, you need to select your fasting method, which includes a range of options. Regardless of which form of fasting you choose, here are some fasting dos and don’ts to keep in mind!  


The Dos 


Pick Your Fast, and Understand the Plan 


With the available fasting options, make sure you understand your “why.” What do you hope to gain from fasting? Is your goal centered on weight loss, religious purposes, recommended by a doctor, or just because you’re curious? From there, decide which form of fasting you want to try, and decide on a timeframe.  


Make sure that you run all of this by your doctor first, especially if you have any health conditions that could be impacted.  


Be Self-Aware and Kind to Your Body 


Fasting can be difficult to adjust to at first. It puts the body through abrupt changes and physical strain. The symptoms we discussed above are very common, so as you begin your fast, pay attention to how you feel. How is your mood, your energy, and your ability to continue your daily routine? Everyone’s body will react differently to fasting, so pay attention to your body’s cues. If you start to feel unwell in any way: dizzy, excessively tired, or unable to continue your daily tasks, you should immediately stop fasting. No health trend is worth your actual health.  


Drink Lots of Water 


Water will be your best friend, assuming you are not participating in a dry fast! It is crucial to always stay hydrated, but particularly when fasting 


Water will help to curb your appetite, keep headaches at bay, and keep your energy up. Make sure to drink plenty of water during your fast, and if you need to, pretend it’s a caramel frappuccino. Whatever gets you through the fasting window successfully! 


Take Your Time 


Just because it’s in the name, does not mean that fasting must happen fast! Allow your body the time it needs to ease into the transition of fasting. You can always build up to more intense fasting practices later, so don’t rush the process. Fasting a little bit at a time to start will make sure you and your body can handle it and get the full benefits.  


Take the Day Off from the Gym 


Time spent fasting is not the time to push yourself to new limits at the gym! Fasting puts a strain on your body, and to exercise on top of that is sure to cause some unpleasant side effects (7). Consider the fast itself as a workout, and allow yourself to take a break from the heavy lifting and cardio! 




Fasting is as much a mental game as it is a physical one. In addition to the body’s physical hunger cues, the mental impact can be challenging. Meditation is a great way to shift your focus to other, better things. There are abundant resources for meditation online and available through various, free apps. Explore some of the options and find one that brings you peace, calm, and confidence during your fast!  


Fasting Don’ts 


Safety is the priority, and no one wants to jump into a health trend, and leave with their health being worse off than it was before. With this in mind, please avoid these fasting don’ts!  


Don’t Immediately Splurge 


When your fast ends, you may be tempted to immediately raid the kitchen and pantry, eating everything in sight. Please don’t. Breaking your fast abruptly, with a large quantity of food can leave you feeling sick, tired, and bloated. You’ll undoubtedly feel hungry after your fast is over, but focus on eating a normal meal and normal quantity, despite the urge to eat more. 


Don’t Do Another Fast, Immediately 


So, you made it through your first fast, finally ate a meal, and survived. You might feel unstoppable and want to fast every day! However, science strongly advises against this. Fasting can be a great tool when used occasionally, but studies have found that individuals who fast for more than 16 or 18 hours per day have a higher risk of gallstones, and may be at a higher risk of needing gallbladder surgery. Additionally, the body needs a regular amount of nutrients to maintain health and wellness, and fasting too often or for too long can hinder this.  


Don’t Fast Without First Consulting Your Doctor 


Fasting is objectively hard on the body. Therefore, it is not recommended for individuals with certain health conditions. Consider that fasting can not only impact blood sugar levels, but also can aggravate mental health symptoms like depression and anxiety. Always check with your doctor before beginning a fasting regimen to make sure that it will be a healthy addition to your lifestyle!  


If you observe these fasting dos and don’ts, your fasting journey can be a rewarding and beneficial practice!

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