Fasting is a practice that is part and parcel of the human experience. Whether you’re doing it for religious, spiritual, or health reasons, there is evidence of people having fasted throughout history.
Today, people fast for many reasons. In the world of health and fitness, fasting is often associated with weight loss. Intermittent fasting in particular has been suggested to have both weight loss and general health benefits.
If you’d like to start fasting but do not know where to start, then you’ve come to the right place. Read on to learn how to prepare for a fast so you can complete it safely and reap all the benefits that are associated with this centuries-old practice.
How Do I Prepare for a Fast the Day Before?
When it comes to fasting, it is ideally best to start planning more than a day before. While fasting can look as easy as “stop eating at time ‘a’ and start eating at time ‘b’”, it is actually more complicated.
In order to be successful at your fast to lose weight or for spiritual/religious reasons, it is best to start preparing at least 3 days or even a week before. Here are some tips on how to prepare for a fast:
Mind over matter
Fasting is more mental than you might realize. An important tip to remember for fasting for beginners is that you will sometimes be hungry. There is no way around this. Your body is used to getting fed at certain times and therefore, fasting will lead to hunger pangs.
Preparing your mind for this means you will be able to hold on and avoid breaking your fast. You should keep reminding yourself why you chose to fast. Write down these reasons where you can see them or set reminders at normal meal times to help you remember why you are doing it.
In addition please remember to be kind to yourself and know your limits. Not everyone who starts a fast can do it for 24 hours straight, let alone for 3 days. Start small and if you have to break your fast earlier than someone else because your body can’t handle it, do it and don’t beat yourself up over it.
Ease into it
In addition to preparing your mind, you must also prepare your body – this is why it’s best to start prepping for a fast a couple of days or even a week in advance.
Gradually start cutting back on how much food and drink you consume. This will enable the body to slowly get used to fasting and that way, it will not go into shock on the day you officially start your fast.
A good way of doing this is by slowly cutting out your usual snacks and only eating the three official meals of breakfast, lunch, and dinner. After a while, you can go down to just two meals a day and ultimately, just one meal a day. This process actually works great for anyone who is looking for tips for fasting for 24 hours.
Reducing how much you eat over time trains the mind and body on when to expect extra food/fuel while also helping the body gradually learn how to adjust energy expenditure and levels throughout the day before the next meal arrives.
Stock up your water
Water is one of the only things that is allowed during the fasting hours of an intermittent fasting meal plan. Not only will it prevent dehydration, it will also help keep your energy levels up throughout the day.
A lack of food also causes headaches, mood changes – irritability – and cramps, all of which can be lessened by drinking water throughout the day/during fasting hours.
Caffeinated drinks such as black coffee and green tea are also great options to have at hand while intermittent fasting. Just make sure they are unsweetened as sugar, honey, maple syrup, etc. will break your fast, and know how much caffeine you can tolerate and what is safe for you.
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We’re not saying that you should avoid exercise altogether, but you should avoid exercising during fasting hours. Fasted exercise or fasted cardio is one of the things that suddenly became popular with intermittent fasting.
Those who advocated for it claimed that it led to more calorie burning and more weight loss in the long term. However, research on this matter is not in agreement.
One study that was published in the Scandinavian Journal of Medicine & Science in Sports found that fasted cardio causes higher fat oxidation than non-fasted cardio, but eating before exercise improves performance and endurance (3).
In an older study published in the Journal of the International Society of Sports Nutrition, researchers found the statement about fasted cardio leading to more weight loss to be untrue. The study involved 20 female volunteers who were divided into two groups.
One group was instructed to do an hour of fasted steady-state cardio, and the other did an hour of non-fasted steady-state cardio. All women worked out 3 days per week for 4 weeks and ate a specified calorie deficit diet. At the end of the study, the researchers found no difference in weight loss or body composition between the two groups (1).
From these findings, it can be seen that there are likely only insignificant benefits to working out or increasing physical activity when fasting.
In addition, fasted cardio may actually be dangerous. According to Healthline, some exercise while intermittent fasting can lead to side effects such as lightheadedness, dizziness, shaking, or even passing out – all of which are due to dehydration or low blood sugar.
If you want to start a fasting diet and still work out, we suggest working out immediately before you have to break the fast, or better yet, 30 minutes after breaking your fast with a snack or 1 hour after with a full meal.
There is no way to avoid thinking about food, particularly during the first few days of your fasting meal plan. One of the best things to add to your ‘what to do before intermittent fasting’ plan is to find healthy distractions to keep you from obsessing over how many hours, minutes, or seconds you have before you can eat.
Some healthy distractions include:
- Catch up on some work
- Pray – if your fasting is for religious reasons, turning to a higher power could help you hold on for longer
- Watch a movie or binge that series you have been putting off
- Get out of the house – that’s where all the tempting food is
- Go for a walk, but keep the pace slow to avoid using up too much energy
- Find a good book, sit in a quiet corner, and read
Eat more protein and fiber
Both protein and fiber from whole foods help keep you feeling full for longer, which is particularly important for weight loss and for fasts (8, 11). Increased satiety will not only help regulate your appetite, it will also help keep you at a calorie deficit, two factors that help you lose weight.
Choose more whole foods over refined carbs or unhealthy snacks
Not only will eating healthier whole foods help improve your health, these foods also contain more nutrients. Fasting for long periods means your body is getting less nutrients than it normally would.
The best thing to do when you break your fast is to make sure you eat foods with plenty of nutrients to replenish your body’s stores and increase your energy.
Refined carbs and other highly processed snacks/foods may curb a craving, but they offer little else to the body. These empty calories and sugars will get used up very quickly by the body, making you feel hungry again sooner. This could take you out of a calorie deficit and ruin your weight/fat loss goals.
If you’re taking medication, consult your doctor before fasting
Some medications cannot be stopped in the name of not wanting to break a fast and certain medications need to be taken at specific times, often with food. Speak to your doctor to avoid any mishaps that could result from missing a dose or by not eating food with your medicine.
If you don’t fast regularly or for extended periods of time, you may not really need supplements.
However, if you do, you may consider looking into this. Fasting often and for long periods means that you do not eat as often or get enough calories as normal and this could lead to nutritional deficiencies (9, 4).
To be on the safe side, speak to your doctor and get some blood tests done to investigate if you have a deficiency or are at risk of one.
Also, if you don’t want to turn to supplements, you can increase your intake of whole foods that are rich in any nutrients you may be missing.
Read more: Is Fasting for 24 Hours Once a Week Healthy?
How Do I Prepare for a Fast for 3 Days?
If you have never fasted before, fasting for 3 days should not be something you initially aim for. You will be better off trying an intermittent fasting for beginners plan to work yourself up to a 72-hour/3-day fast.
If you’ve done 24-hour (or longer) fasts before, then you may be able to last all 72 hours. Some things you should do to ensure you fast safely for 3 days include:
Eat well before the fast
This meal will obviously not last in the body for 3 days, but it will help the first few hours go by easily
Rest as much as possible
Do not work out and if you can, don’t go to work either. It is best to schedule a 72-hour fast for a weekend or a holiday leading up to a weekend
Do not fast if you are on medication or if you are underweight
Seek medical attention
Fasts that last beyond the 24-hour mark are not recommended and often raise health concerns. Be sure to speak to a doctor before starting a 3-day fast (aka water fast)
If possible, have medical supervision as you undergo your fast
Long fasting is not recommended for anyone under the age of 18 or over the age of 65
Pregnant and breastfeeding women
Should not fast, and those with any medical conditions should speak with their healthcare provider first
What Should You Avoid Before a Fast?
If you are fasting for religious reasons, your religious texts should provide you with proper guidelines on what you should avoid before starting a fast.
If you are fasting for a blood test, you will most likely be requested not to smoke, eat, or drink anything – except water – before the test (2).
If you are doing a short fast for health or weight loss reasons:
- Avoid jumping straight into the fast – ease into it for a better chance of success
- Avoid eating ultra-processed foods right before you fast – they are empty carbs that will make you feel hungrier faster
- Avoid binging – eating too much will not keep you fuller for longer and you will most likely get sick instead
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How Should a Beginner Start Fasting?
- Choose your preferred fasting method – There are many fasting regimens in the intermittent fasting world. The most popular option is 16/8, which involves a 16-hour fasting window and an 8-hour feeding window. Other beginner-friendly options include 12/12 and 14/10.
- Stock up on water, unsweetened coffee, black tea, and green tea. These are the three things that will tide you over during the fasting window.
- Do a grocery shop and clear out the fridge/pantry of any overly tempting foods.
- Do meal prep. No one wants to start cooking after hours of fasting and feeling hungry. Do a meal prep and divide up your meals into ready-to-eat portions that can be quickly heated up when it’s time to eat.
- Plan your workouts around your feeding windows. Work out either right before you need to break your fast, ensuring that you can fuel up as soon as possible, or soon after your first meal to avoid working out in a fasted state.
What Should I Include in My Intermittent Fasting 7-Day Meal Plan?
As you are fueling your body less than you normally would, your meal plan for this period should be as healthy and nutritious as possible. Every good intermittent fasting meal plan should include the following:
- Foods that are rich in protein, such as lean meats, fish, eggs, tofu, nuts and seeds.
- An assortment of vegetables – always remember to eat a rainbow. The more colors on your plate of vegetables, the better. Shop for both starchy and non-starchy vegetables, in addition to leafy greens.
- Legumes and lentils for a plant-based protein and complex carbohydrates option.
- Whole grains – they are rich in fiber, which helps keep your calorie intake down and helps you feel full for longer during the fasting window.
What Age Should You Start Fasting?
It is recommended that people start fasting no earlier than the age of 18. Different religions may have different rules for this.
Is the first day of fasting the hardest?
That depends. For some, the first day is the hardest, while others say that the second and third days are the hardest.
How much weight can you lose on a 72-hour fast?
Any weight that is lost on a 72-hour fast is negligible. This is because during such fasts, you only tend to lose water weight, rather than body fat. To actually lose body fat, you must exercise, eat a healthy diet, and perhaps try intermittent fasting for several weeks or months before you see any actual results.
How long should I fast to cleanse my body?
Unless it’s for religious or spiritual reasons, normal fasting will not cleanse the body or get rid of toxins. Your body already has a detoxification system in the form of the liver, kidneys, lungs, skin, and digestive system that works day and night to detoxify itself (7).
What electrolytes do I need when fasting?
Electrolytes are essential for basic life functioning as they help with the control of your fluid balance, blood pressure regulation, muscle contraction – including heart muscles, and maintenance of the correct acidity in your blood.
Significant electrolytes that the body needs include sodium, potassium, chloride, magnesium, calcium, phosphate, and bicarbonates – all of which can be found in food and drinks (5).
When fasting, you tend to lose the electrolytes in the body (6). Water – even tap water – can help you replenish the electrolyte levels in the body (10). However, once your fast is broken, you should try to eat foods containing the aforementioned minerals to ensure that even when your electrolyte levels go down when fasting, they aren’t at dangerous levels.
The Bottom Line
The process of preparing for a fast is more detailed and complicated than many people think. To successfully go through this process without breaking halfway, both your mind and body must be ready long before the first day of the fast.
Follow the steps above and you will have a much easier time than if you simply jump into it with little to no preparation. Be sure to speak to a doctor before you change your eating habits.
This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!
- Body composition changes associated with fasted versus non-fasted aerobic exercise (2014, ncbi.nlm.nih.gov)
- Can I eat and drink before having a blood test? (2021, nhs.uk)
- Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis (2018, onlinelibrary.wiley.com)
- Effects of Periodic Religious Fasting for Decades on Nutrient Intakes and the Blood Biochemical Profile (2021, ncbi.nlm.nih.gov)
- Electrolytes (2023, ncbi.nlm.nih.gov)
- Fasting—A review with emphasis on the electrolytes (1971, amjmed.com)
- ORGAN SYSTEMS: DETOXIFICATION (n.d., vetmed.tamu.edu)
- Protein, weight management, and satiety (2008, sciencedirect.com)
- The influence of fasting on energy and nutrient intake and their corresponding food sources among 6-23 months old children in rural communities with high burden of stunting from Northern Ethiopia (2022, nutritionj.biomedcentral.com)
- The mineral content of tap water in United States households (2013, sciencedirect.com)
- Unravelling the Effects of Soluble Dietary Fibre Supplementation on Energy Intake and Perceived Satiety in Healthy Adults: Evidence from Systematic Review and Meta-Analysis of Randomised-Controlled Trials (2019, ncbi.nlm.nih.gov)