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It is safe to say most of us stick to the standard three meals a day, maybe with a snack or two in between, to keep us fueled and satisfied from morning till night. Therefore, the idea of fasting, or not eating for extended periods of time, can seem a little extreme (or just painful!). Yet, intermittent fasting is now becoming one of the most popular habits adopted by people looking to lose weight and optimize their health.
WHAT IS INTERMITTENT FASTING?
Intermittent fasting is the method of restricting the window of time in which you eat: either on a daily, weekly, or monthly basis. The principle of this technique is that, by minimizing the time spent eating, you are giving the body a period to fully digest food, store nutrients, and restore the body before the next eating period. This has a number of health benefits but also encourages people to make better food choices.
With the rapid increase in interest toward intermittent fasting over the last few years, it can seem to some people as just another "health fad". However, some scientists and historians believe that having periods of fasting is a much more natural way for humans to eat versus the "3 meals, 2 snacks a day" modern approach. Even back in hunter-gatherer days, when food wasn't always guaranteed, humans would very commonly go without food for 1 or 2 days while they were traveling or when struggling to find their next meal.
You can also find fasting practices or periods of abstinence from food as acts of devotion in many religions and cultures. For example, during the yearly Islamic Ramadan, followers don't eat between sunrise and sunset for 30 days. Similarly, the yearly Christian ritual of Lent is considered to be a time to fast to honor Jesus Christ's 40-day journey in the desert. Intermittent fasting is also present in Buddhism where some monks often chose not to eat after noon every day.
DIFFERENT METHODS OF INTERMITTENT FASTING
When considering intermittent fasting as a way to improve your health, it can be a tool to help you gain more control over when or how you eat throughout the day or week.
The 16:8 Method
This is the most common way for people to intermittent fast as it can be adapted and altered to fit your lifestyle. The basic concept is that you fast for 16 hours and eat during the remaining 8-hour window: the timing of the 8-hour window is completely up to the individual. The best way to achieve this method is to start the fast before you go to bed. For example, if you eat dinner and stop eating at 6pm, you then fast through the night and into the morning where you can break your fast at 10am.
If this initially seems tricky, maybe start by having a 10-hour eating window (9am-7pm) and incrementally try to reduce it to 8 hours over the course of a few months. Once you get comfortable with the 16:8 method, some people choose to extend it further to 18:6 or even 20:4.
The 5-2 diet
The 5-2 diet takes fasting into more of a weekly meal plan rather than daily. The idea is that you eat a normal, unrestricted but healthy balanced diet for 5 days of the week, then, on 2 non-consecutive days of the week, you only consume around 500-600 calories. This diet has become popular as more people are finding it an easier way to diet versus the traditional way of calorie-restricting every single day. On the 2 calorie-restricted days, many people find either eating three small meals or two large meals, full of fiber and protein, throughout the day helps them to reduce hunger pains and keep them on track.
One meal a day
Often called the Warrior diet, this is a 20:4 method of intermittent fasting where you eat your daily calorie intake (normally between 2,000-3,000 calories) in one large meal. This extreme diet is not generally recommended by nutritionists but is often adopted by people looking to gain certain weight goals to build lean muscle and strength. There are technically no restrictions about what can be eaten during the 4-hour window but people are encouraged to find their calories in high-protein wholefoods rather than junk food.
24-48 hour fasts
The "Eat-Stop-Eat" approach is when people choose to not eat for 24 hour periods, possibly several times a week. This is often done by essentially skipping two meals: ie. having dinner and then not eating until the following day's dinner.
Similar to the concept of detoxing, some people chose to do these longer 24-48 hour fasts once every month or even once every 3, 6, or 12 months. There are many variations with some people only choosing to drink water during the fast while others choose to drink cold-pressed vegetable juice or bone broth to provide a source of nutrients without the calories.
A fast that lasts longer than 48 hours is not considered intermittent fasting. It is advised to only do an extended fast under the supervision of health professionals.
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HEALTH BENEFITS OF INTERMITTENT FASTING
Research has shown that even just having 12 hours of fasting every day can significantly benefit people who are trying to lose weight or regain their health. However, if you can take it a step further and fast for periods of 16-18 hours regularly, then the health benefits could multiple significantly.
Intermittent fasting can offer an alternative solution to time-consuming calorie counting and other weight loss methods. Reducing the eating time window, rather than focusing on how much you are eating, allows the body to fully digest, rest and reset, and has shown to help restore a healthy metabolism in both obese and overweight people. The weight-loss benefits of intermittent fasting are significantly higher if adopted alongside a healthy well-balanced diet.
Brain & Heart Health
Fasting regularly promotes a healthier blood flow throughout the body, meaning brain and heart health are dramatically improved. This is the result of a more steady blood sugar level as you are limiting the amount of cholesterol and sugar that is normally being constantly added to your body. It has also been claimed that fasting promotes healthy nerve cells and could be a preventive measure against Alzheimer's disease.
Inflammation & Chronic Disease
When we are constantly eating, our body puts all its energy into the digestive system to try and digest all the food, store the nutrients and get rid of waste. If we stop eating, we allow time for the body to use its energy to restore and heal. One significant outcome of fasting is the increased level of human growth hormone which is what we use for cellular repair and muscle growth. It has been shown that fasting for 14-16 hours allows the body to heal quicker: it has shown to reduce inflammation for people who regularly exercise and even helps with chronic illnesses such as asthma and arthritis.
It is often claimed that intermittent fasting is the ultimate solution to helping you live for longer. However, this has been hard to fully study on humans as so many other factors are at play when trying to figure out people's life expectancy. However, lab studies looking at intermittent fasting on mice and rats have shown that regular periods of fasting versus having a constant supply of food did increase the length of life in the rodents. Whether this translates to humans, science is working on that. But from a logical point of view, intermittent fasting is known to reduce the risks of many lifestyle diseases all of which are more likely to occur in older age. Reducing the risk of heart disease, cancer, or diabetes through intermittent fasting could increase the chance of people living longer, vibrant, healthier lives.
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INTERMITTENT FASTING GUIDELINES
If you think intermittent fasting could work for you and your lifestyle, starting can be as easy as waking up tomorrow morning and seeing if you can hold off having breakfast for a couple of hours longer than usual. You don't really need to do anything before you start trying to fast but it is always best to have a well-balanced healthy diet before adopting other healthy lifestyle changes.
From the different methods explained above, there are a variety of ways to fast so ultimately it is up to you what you think will work best. However, the 16:8 method is usually a good place to start.
Troubleshooting, what to be aware of: When first starting to fast, the first few days or weeks may feel uncomfortable as your body adjusts to the new eating pattern. Here are some tips and tricks to help you.
Hunger pangs: Often our body can trick us into thinking we are hungry when we are just thirsty. Whenever you think you are feeling hungry, first sip on a large glass of water and then see how you feel. Also, try to have herbal teas, flavored waters, or even an electrolyte supplement to keep your taste buds and stomach at bay.
Feeling weak: If you do feel sluggish try going for a walk in the sunshine and fresh air or take a cold shower. After a few days, if nothing changes and you don't have an increase in energy levels, then maybe reduce the fasting window to something more suitable for you.
- Thinking constantly of food: if you find yourself constantly thinking about food and you're just staring at the clock wanting the fast to be over, you will find intermittent fasting harder to maintain. Try to incorporate a routine that will keep you distracted during the fasting period. For example, if you try to fast in the morning until 11am, schedule an early work meeting or go to the gym or run errands in the car. Keeping yourself busy and active will keep you focused on your daily tasks and away from the temptation of the fridge.
Best ways to start and break a fast
Last meal before the fast: make sure it is packed with protein and fiber so that it keeps you fuller for longer. Also, try to incorporate some whole grains, leafy greens, and nuts or seeds to give you a boost of micronutrients and vitamins. You should be full, satisfied, and full of energy rather than feeling stuffed, too full, and sluggish.
- How to break the fast: with intermittent fasting that lasts no more than 18 hours, you don't need to be too cautious when breaking your fast. However, it is recommended to go for something like a smoothie or soup as it is easy to digest and won't shock your digestive system. Then, during your eating window, continue to make sure you are making healthy choices so when you are facing your next fasting period, your body is full of vitamins, minerals, and energy to take you through your next fast.
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RISKS OF INTERMITTENT FASTING
To some, intermittent fasting can seem like an elaborate way of describing starvation and encouraging people to lose weight by simply not eating. There are significant risks to intermittent fasting and it is definitely not recommended for everyone. For example, people with eating disorders and who struggle to maintain a healthy calorie intake should not be adopting intermittent fasting. However, intermittent fasting is not about reducing the number of calories consumed in a day but rather reducing the window of time in which those calories are consumed.
Fasting, and especially fasting for multiple days, is still very controversial amongst health professionals: it is tricky to ethically justify telling people not to eat. However, there is little harm in choosing to eat dinner a little earlier and breakfast a little later. If you are looking to try more extreme types of intermittent fasting, it is often suggested to get yourself checked by your doctor before you start and then have regular check-ups while your body adjusts to your new lifestyle.
INTERMITTENT FASTING RESOURCES
The Fast Diet by Dr. Micheal Mosley & Mimi Spencer
This book kick-started the rise in the 5:2 diet and continues to provide insight into intermittent fasting and losing weight without the constant hassle of calorie counting. The revised and updated version now contains easy simple recipes to help you manage those two 500 calorie days.
Fast. Feast. Repeat by Gin Stephens
To accompany her successful online community, Gin Stephens' book helps to define intermittent fasting as a lifestyle choice rather than a diet, providing insight into why focusing on overall health can be the catalyst towards weight loss. With its 28 day guide, this book helps to make intermittent fasting work with your specific lifestyle.
The Obesity Code by Dr. Jason Fung
In this book, Dr. Fung suggests intermittent fasting as the solution to "yo-yo dieting" and weight loss that actually lasts. With a deep dive into how your hormones could be the reason why certain people struggle with obesity, this book looks at how managing the intake of food with intermittent fasting, plus adopting a more high-fat diet, could be the final act to rid yourself of excess weight.
Intuitive Fasting by Dr. Will Cole
The concept of "intuitive fasting" that is promoted in this book will encourage you to really understand how your body may feel and react when fasting. The four-week fasting plan is a great tool to get you started on incorporating intermittent fasting into your life by encouraging you to make healthy choices that work with your body’s natural cycles.
FREQUENTLY ASKED QUESTIONS
- Can I Exercise While Fasting?
If you are doing a 16:8 intermittent fast, exercising regularly and even exercising a couple of hours before breaking your fast could be very beneficial. However, if doing longer fasts that last 24 hours or longer, it is recommended to only go on steady walks or do some gentle stretching or yoga, saving more intense exercises for when you can eat to restore your energy levels.
- Can I Drink Anything Other Than Water?
Some people choose to fast while having soups and juices, so they are still consuming very minimal calories. If you are doing a strict water fast, you want to make sure you don't accidentally break the fast by consuming any sugar. Therefore, it is usually recommended to only drink herbal teas or water with lemon or apple cider vinegar. These may help to reduce cravings and provide some flavor to plain water. However, it is possible to drink small amounts of black tea or coffee and also bone broth without breaking your fast.
- Who Should Avoid Intermittent Fasting?
It is advised that children, women who are pregnant or breastfeeding, and the elderly should not undergo any form of intermittent fasting. Also, if you do have any medical condition, such as high blood pressure or diabetes, it is best to seek advice from your doctor about whether intermittent fasting is suitable for you.
- What If I Am Working/Travelling/Socialising & I Can't Stick To A Regular Intermittent Fasting Schedule?
Some people like to take a more ad-hoc approach to fasting and try to incorporate different fasting windows into their routine depending on their schedule. For example, if you have the time and energy you might be inclined to extend your fast to 18 hours over the weekend, while on the days or weeks where you have more social, work or family commitments, you may have to reduce your fasts to 12 or 14 hours. As long as you are maintaining a healthy balanced diet, you can work with intermittent fasting in whatever way works for you and your lifestyle.
THE BOTTOM LINE
Intermittent fasting gives the body a break from digesting food and time to heal, resulting in many potential long-term health benefits. Trying intermittent fasting for yourself can be a very empowering way to gain more control over how you eat and offer you an alternative solution to calorie-counting diets.
The information provided in this article is not nutritional or medical advice. Please read our disclaimer.