Adding intermittent fasting to your diet is an effective way to throw your metabolism a curveball, keep insulin levels low, and encourage faster weight loss. The intermittent fasting method that you follow will have a lot to do with what fits into your lifestyle. In this post, discover ten ways to fast.
Intermittent Fasting Schedules – At-A-Glance
12:12 – 12 hours fasting and a 12-hour eating window.
16:8 – 16 hours fasting and an 8-hour eating window.
The Warrior Diet (20:4) – 20 hours fasting and a 4-hour eating window.
One-Meal-a-Day (OMAD) – 23 hours fasting and a 1-hour eating window.
Fat Fast – Eating only high-fat foods. Eat when hungry and stop when full.
5:2 Diet – Eat normally for five days and limit calories to 500-600 calories for two days.
Alternate Day Fasting – Fast every other day. Extreme version: No calories on fasting days
Modified Alternate Day Fasting – Eat about 25% of your normal caloric intake on your fasting days.
Extended Fasts – Fasts lasting longer than one day.
Instinctive Intermittent Fasting – Follow your instincts and skip a meal when it fits your schedule.
10 Intermittent Fasting Schedules for Weight Loss [Video]
In this video, you’ll learn…
- The most common intermittent fasting schedules.
- Tips on where to begin and how to fast as safely as possible.
- Additional intermittent fasting methods.
Popular Intermittent Fasting Schedules
Many of the popular intermittent fasting schedules fall under the umbrella of time-restricted feeding, which is the technically correct term for restricting the number of hours within a day that you consume calories (1).
12:12 Intermittent Fasting
12:12 Intermittent Fasting can be an effective place to start if you are new to fasting as it has been shown in animal research to reduce obesity (2).
This method simply requires you to split your day into two 12-hour periods that cycle between eating and fasting.
This can be thought of as an overnight fast. For instance, if you’ve ever had a blood test scheduled for the morning, you were likely told to stop eating after dinner and fast overnight. Performing a 12:12 intermittent fast is no more complicated than that.
16:8 Intermittent Fasting
There are many ways you can split your day up when you practice time-restricted eating, but perhaps the most popular and best-studied method is 16:8 intermittent fasting.
The popularity of this method has a lot to do with the weight loss benefits as well as the ease at which it can fit into your life (3).
For instance, many people find that not eating after dinner and then skipping breakfast the next day fits their lifestyle.
By doing this, you can enjoy being social at dinnertime. You can then perform the last stage of the 16-hour fast in the morning when life is busy and it’s easy to keep your focus off of food.
The Warrior Diet (20:4 Intermittent Fasting)
Another method of fasting is referred to as The Warrior Diet by Ori Hofmekler, which is simply a spin on time-restricted eating that requires a 20-hour fast with just four hours in which to consume all of your calories for the day.
While many of the intermittent fasting methods outlined in this post do not specify a particular way of eating, the Warrior Diet puts an emphasis on filling up on whole unprocessed foods.
This is meant to mimic ancient warriors, who fasted most of the day and then feasted for a few hours of the same day.
OMAD (One-Meal-a-Day) (23:1 Intermittent Fast)
OMAD or One-Meal-a-Day Fasting is the practice of narrowing your eating window to just one hour of the day.
This method obviously requires you to fast for 23 hours, so it is not far off from a full 24-hour fast. This fast was popularized by Brad Pilon in his book, Eat-Stop-Eat. Pilon advocates practicing these full-day fasts once or twice a week.
Things to Consider before Starting
More Research is Needed
The health benefits or consequences of these types of fasts need more evaluation. For instance, some animal models showed OMAD to be less effective at controlling body fat than having a large and small meal throughout the day (4).
Talk with Your Doctor
Do not jump into a fasting routine without being assured by your doctor that you are healthy enough to perform a fast.
Because you are not consuming food during your fast, you need to be careful with medications that may be affected by your food intake or changes in your blood sugar.
Err on the side of caution. Start with a simple form like 12:12 and keep your doctor in the loop as you change your eating pattern.
Non-Caloric Drinks are Allowed
In all of the fasts discussed, it is common to allow non-caloric drinks, including water, coffee, and tea during the fast.
Other Intermittent Fasting Methods
An alternate method is to allow fat calories during your fasting window, which brings me to the next intermittent fasting method which can be referred to as a Fat Fast.
This term has yet to get a solid definition and there are variations in how it is performed. One method of Fat Fasting involves eating only high-fat foods as spelled out by Dr. Jason Fung on his “Intensive Dietary Management” website.
My husband’s version helped him successfully reach his 80-pound weight loss goal at age 56. It involves utilizing time-restricted eating but allowing heavy cream or other forms of pure fat in his coffee throughout the day.
Fat fasts work because fat consumption is very hunger satiating. It mimics the effects of a complete fast by keeping blood sugar or insulin levels low. When these elements are low, your body is able to pull the fat out of storage and use it for energy (5).
The 5:2 Diet
The 5:2 diet is another way to bring intermittent fasting into your weekly routine. It involves eating as you normally would for five days and then limiting your calories to 500 (women) or 600 (men) calories for the remaining two days of the week.
You can choose which days to fast as long as you do not do them back to back. Fasting on a Friday and Sunday would fit this method.
As with many of these methods, there is not a ton of research to support them, with many being the creation of individuals that found something to be effective for weight loss. The 5:2 Diet which is also known as the Fast Diet was popularized by Dr. Michael Mosley.
Alternate Day Fasting
The concept of fasting one day and feasting another is also seen in a method of fasting known as alternate day fasting.
There are two camps when it comes to this type of fast. The more extreme version is to consume no calories for 24 to 36 hours and then eat whatever you want within your eating window the next day (6).
On my 2 Fit Docs YouTube Channel, we experimented with Alternate Day Fasting. When it comes right down to it, a full fast every other day felt a bit brutal.
We also experimented with Modified Alternate Day Fasting, which is the less extreme of the two versions of this fast.
Modified Alternate Day Fasting
Most of the research supporting Modified Alternate Day Fasting has been performed by Dr. Krista Varady who wrote the book, The Every Other Day Diet.
The modification allows you to eat about 25% of your normal caloric intake on your fasting day, which is often simplified to allowing 500 calories on those fasting days.
My husband, Keith, and I experimented with this method and found it very doable.
Positive weight loss and health benefits uncovered from the research show that modified alternate-day fasting is worth a look (7).
Extended fasts are fasts lasting longer than one day.
In his book, The Complete Guide to Fasting, Dr. Jason Fung discusses the potential benefits of longer fasts, which include weight loss and reduced insulin levels, but also cautions about the increased risks of extending your fast.
These risks include, but are not limited to, complications for diabetics, heart patients, and those taking medications.
If extending your fast is something that you’re interested in, you’ll do best to do so while being monitored by your doctor.
Instinctive Intermittent Fasting
The last method is instinctive intermittent fasting. In other words, follow your instincts and skip a meal when it fits your schedule.
The only thing this method requires you to do is listen to your body. For instance, if you are not feeling hungry for breakfast, put off eating for a few hours or skip breakfast altogether and start your eating day with lunch.
Your body is well equipped to handle periods of no food intake. In fact, it weathers that storm each night as you sleep.
Starting with a Solid Foundation
No matter which intermittent fasting method you choose, it is easiest to perform if you prime your body by eating a low-carb or keto diet before starting. This style of diet stabilizes your blood sugar, preventing sudden crashes.
If you’re not sure how to make these diets work in your life, I have a number of programs that can help that you.
(1) Longo, Valter D., and Satchidananda Panda. “Fasting, circadian rhythms, and time-restricted feeding in healthy lifespan.” Cell metabolism 23.6 (2016): 1048-1059.
(2) Sundaram, Sneha, and Lin Yan. “Time-restricted feeding reduces adiposity in mice fed a high-fat diet.” Nutrition research 36.6 (2016): 603-611.
(3) Smith, Siobhan T., Jordan C. LeSarge, and Peter WR Lemon. “Time-Restricted Eating In Women-A Pilot Study.” Western Undergraduate Research Journal: Health and Natural Sciences 8.1 (2017).
(4) Fuse, Yuta, et al. “Differential roles of breakfast only (one meal per day) and a bigger breakfast with a small dinner (two meals per day) in mice fed a high-fat diet with regard to induced obesity and lipid metabolism.” Journal of Circadian Rhythms 10.1 (2012): 4.
(5) Perry, Rachel J., et al. “Leptin mediates a glucose-fatty acid cycle to maintain glucose homeostasis in starvation.” Cell 172.1-2 (2018): 234-248.
(6) Stekovic, Slaven, et al. “Alternate day fasting improves physiological and molecular markers of aging in healthy, non-obese humans.” Cell metabolism 30.3 (2019): 462-476.
(7) Alhamdan, B. A., et al. “Alternate‐day versus daily energy restriction diets: which is more effective for weight loss? A systematic review and meta‐analysis.” Obesity science & practice 2.3 (2016): 293-302.
About the Author
Dr. Becky Gillaspy, DC graduated in 1991 with a Doctor of Chiropractic degree from Palmer College.