Updated: Jun 30
IF is a way of eating that employs a fasting window of 24 hours or less. IF has been used to facilitate weight loss, build lean muscle mass, improve digestion, decrease inflammation throughout the body as well as to increase energy levels.
IF is a way of life, not a diet. Our bodies are designed to fast and feed in regular cycles – our first meal of the day is after all called BreakFast! We are all very good at the feeding part but we miss the opportunity to take full advantage of the fasting part. During fasting hours, our bodies continue working and when not overwhelmed with the work of digesting food, our bodies can focus on repairing cells, healing illness as well as detoxifying our blood. More on the benefits of IF later.
Employing IF as a lifestyle choice facilitates our physiological organism to function at a more optimal frequency, thereby impacting our health and well-being in a plethora of ways – from digestive health to emotional balance, it all begins (and ends!) in the gastrointestinal track.
IF is not the same as water-only fasting; which consists of consuming ONLY WATER for a period of longer than 24 hours. That is a wholly different type of fast and not the type of fasting lifestyle we are discussing here. IF allows for ‘zero calorie’ beverages to be consumed during the fasting hours (lemon juice, ACV, tea, black coffee) and one type of IF allows for up to 500/600 calories to be consumed on ‘fasting days’. These allowances differentiate IF from medically supervised water-only fasting.
A key component to successful IF is your nutrition during your feeding hours. Be sure to focus on nutrient dense foods to ensure your body receives the vitamins and minerals it needs to perform optimally. Remember that food is your only fuel and consuming nutrient dense options during your feeding hours (no matter the type of IF you choose) will better fortify your body to be able to do the healing work during your fasting hours.
Types of Intermittent Fasting
Type of IF: The 5:2 Diet
Developed by: Dr. Michael Mosley
You eat normally five days during the week. For two days each week you ‘fast’ for 24 hours. During those ‘fasting’ days, women are allowed up to 500 calories and men up to 600 calories.
Eat normally on Sunday, Monday, Wednesday, Friday and Saturday
Fast (limiting calories to 500 or 600 depending on gender) on Tuesday and Thursday
This type of fasting routine is beneficial for the overall restriction of calories. Though not technically a fast, the benefits of the calorie restrictions on the ‘fasting days’ are a good way to introduce yourself to IF and the caloric restriction impacts the body in a similar way to more intense IF programs.
Type of IF: Leangains
Developed by: Martin Berkhan
Level: Beginner to Advanced (as you wish!)
With Leangains, you will choose a set time for fasting each day. If you are new to IF, begin with a 12:12 practice and slowly build up to 16:8. If you are an experienced IF practitioner, increase the Leangains fast/feed ratio up to 20:4.
12:12 – twelve hours fasting and twelve hours feeding
16:8 – sixteen hours fasting and eight hours feeding
20:4 – twenty hours fasting and four hours eating
During the fasting hours you are allowed to consume ‘zero calorie’ drinks. These include lemon juice in water, ACV with water, black coffee and tea. During the feeding hours you are allowed to eat what you like whenever you like. Split up your calorie intake during your feeding window to fit your lifestyle and schedule. During your feeding hours, the frequency of your meals is irrelevant. You can eat as often as you wish during your feeding hours, and eating only one meal is fine too.
One point of guidance is to be sure to leave a minimum of two hours between your final calories of the day and your bedtime. This will allow for digestion to begin before you sleep as well as put a good chunk (up 70%) of your fasting window in your bed sleeping!! Maybe dreaming of food!!
The key is to be consistent and not shock your body into a new pattern each day. Try to keep your fasting/feeding hours consistent. If you begin your fast at 7pm one day, try to begin as close to 7pm each day. Your body will adjust to a new consistent routine much more easily than to a hit-and-miss approach to IF.
Type of IF: Eat.Stop.Eat.
Developed by: Brad Pilon
This type of IF practice is similar to The 5:2 Diet approach in that two days during each week you fast – though this time it is a full 24 hours without any calories. Each week you will choose two days during which you will fast for a full 24 hours. Zero calorie drinks – lemon juice, ACV, black coffee, tea – are allowed during the fasting hours.
Eat normally on Sunday, Monday, Wednesday, Thursday and Saturday
Fast (zero calorie drinks are allowed) on Tuesday and Friday
: Begin fasting Monday night and fast until Tuesday night (ex: 7pm to 7pm)
: Eat as you wish on Wednesday and Thursday (until fast begins again)
: Begin fasting on Thursday night and fast until Friday night (ex: 7pm to 7pm)
: Eat as you wish on Saturday, Sunday and Monday
: Begin fasting cycle on Monday night, etc …
This is a more advanced type of IF and I suggest you begin with one day a week and build up to two after a few weeks. Again, consistency is key to a successful IF lifestyle and it is better to start slowly in order to ensure you will have the patience to keep with it.
Type of IF: Warrior Diet
Developed by: Ori Hofmekler
If you choose this type of IF, you will eat one meal a day in the evening. There is no calorie or macronutrient restriction for this meal. Throughout the ‘underfeeding’ hours you are allowed to consume fresh/raw fruits and vegetables but are not allowed any fats, sugars, salts or carbohydrates. During the ‘overfeeding’ stage, you will eat one meal – and anything you wish can be a part of that meal, no restrictions.
During the ‘undereating’ phase you are allowed ‘live’ foods, zero calorie beverages (lemon juice, black coffee, tea, ACV), and light proteins found in live foods (ex: nuts, avocadoe, etc.). You are NOT ALLOWED any carbohydrates or starches during the undereating phase. Fruit juices are not allowed during the ‘undereating’ phase though FRESH VEGETABLE JUICES are highly recommended.
During the ‘overeating’ phase (your one meal of the day in the evening) it is recommended that you include all macronutrients in your meal. Ideally, you will begin your meal with raw food (salad) then move onto a cooked dish (protein based dish) and finally you will eat food with plenty of carbs and fat (grains/pasta/rice based dish).
Plan your ‘overfeeding’ meal to best optimize its digestion by following the order of macros introduced into your body (raw/protein/carbs/fats). There is no calorie counting required for this type of IF.
This is an advanced IF practice for those who employ IF techniques daily and want to push themselves a bit further. With this type of IF it is crucial to be consistent with your once daily mealtime. Try to consume your meal between hours 20 and 24 of your ‘fast’. I put it in quotes due to the allowance of fresh produce during the ‘fasting’ hours.
Those are the four best known and studied IF techniques summarized. Choose wisely and begin your new adventure with IF – the benefits are on their way!!
I have said it before but it is worth repeating …
A key component to successful IF is your nutrition during your feeding hours. Be sure to focus on nutrient dense foods to ensure your body receives the vitamins and minerals it needs to perform optimally.
Remember – IF is a lifestyle choice, one that can be practiced each and every day of your life. Explore the IF options and find the one that fits best into your schedule and preferences.
And keep at it … it has taken some time for your body to learn its current feeding schedule, allow it time to adjust to a new schedule now so that you can fully reap the health benefits of IF.