Today, a well-known dietary management group asked people on social media to name their favourite fasting protocol and what struck me was that there were as many different styles of intermittent fasting, as people.
Here are some of the answer that were posted;
- OMAD 20:4
- eat lunch/dinner Tues/Thurs/Sat/Sun, Fast Mon/Wed/Fri
- 42 x 3
- 24 hour fast 1 x week, 48 hour fast 1 x month, 4 day fast 1 x year
- IF daily : 2 meals, alternate day, OMAD occasionally
- 36 hrs on Mondays and Thursdays, 18:6 the rest of the days
- OMAD three days a week. Two meals four days a week. LCHF when eating twice.
- ADF on MWF, two meals plus snack on the off days
- Sunday dinner to Tuesday first meal when hungry
- OMAD with ADF and extended fasts of 72 hours to 7 days throughout the year
- EF of 5 plus days every 5-6 week
- 16:8 with an eating window 11 am to 7 pm
- 42 x 3 times a week plus 18:6 on feasting days
Definition of Terms
OMAD = one meal a day
IF = intermittent fasting
ADF – alternate day fasting
18:6 = fasting 18 hours / day, six-hour eating window
20:4 – fasting for 20 hours / day, 4 hour eating window
EF of 5+ days = extended fasting for 5 or more days
Internal and External Perceptions of Intermittent Fasting
I think to someone reading this who had no experience with these different types of “intermittent fasting”, this would seem terribly complicated. And difficult. It might even seem like an ‘initiation rite’ of sorts, or perhaps a competition as to who does the most radical type of fasting.
While fasting has therapeutic benefits of enabling insulin levels to fall, those who fashion their diets after books that have been written on fasting often see it as ‘part and parcel’ of a very high fat / moderate protein “keto diet”.
It’s important to understand, as I’ve said many times in different articles such as this one, there are different types of “low carb” diets and different types of “keto diets”. Not all are super high fat! Some versions do not have people eating lots of whipping cream and coconut oil and bullet-proof’ing everything and eating ‘fat-head’ bread and pizza, with tons of bacon and avocado. And not all involve “fasting”. In fact, some approaches caution against it, due to the potential of loss of muscle mass.
More than One Type of Low-Carb or “Keto” Diet
Some approaches are high protein with as much fat as people want, whereas other encourage moderate to high level of lean protein with visible fat removed. There is no one “low carb” or “keto diet”, even though when most people think of “keto” they envision the high fat version, which alternates with different types of fasting.
It is understandable though, that if someone is going to eat huge amounts of fat in a day, that it is followed by longer or shorter periods of intermittent fasting, which balance it out. It also balances out the cost of eating that way, as one only has to buy food for 1/2 the amount of time.
My Answer to the Question
I answered the question “what is your favourite fasting protocol” as follows;
My favourite ‘fasting protocol’ since my type 2 diabetes is in remission isn’t really “new”.
According to circadian biologists like Dr. Satchidananda Panda of Salk Institute and Dr. Matthew Walker of University of California at Berkeley, this is probably pretty close to how mankind ate for that last few millennia; until the advent of the gas and then electric light and refrigeration.
Until we could artificially extend ‘day’ as long as we wished simply by leaving the lights on — and pushing it even further with our smartphones in bed, people ate well before nightfall and went to sleep when it got dark and didn’t eat until the first meal the following day. According to Panda, the master circadian “clock” in our suprachiasmatic nucleus of our brains are set by these ~24 hour day/night cycles and when we are first exposed to light, and the individual circadian ‘clocks’ in our organs are ‘synced’ by when we sleep and eat.
Literally, for thousands of years, people didn’t eat from after their last meal of the day (which was quite a while before they slept) and then didn’t eat until the first meal the next day (which wasn’t as soon as they opened their eyes, either!). Even after the invention of electric lighting and refrigeration, many people had a long period of time between when they finished dinner and the next morning when they ate breakfast (the meal that broke the “fast”). It would seem that our species did pretty well eating that way, and didn’t seem to suffer the metabolic diseases of overabundance we are now inflicted with.
Given our body’s circadian clocks are literally tied to these approximate 24/hour cycles, and ‘synced’ by when we eat / don’t eat and sleep, eating in accordance with these natural circadian rhythms (when it functioned best for thousands of years) just seems to make “sense”.
In light of this, my general “philosophy” for healthy individuals about when to eat and when to “fast” is simple;
- eat real, whole food when genuinely hungry, as part of a meal
- don’t eat between meals (avoids keeping insulin high, allows it to fall between meals)
- Don’t eat after an early-ish last meal of the day (~3 hours before bedtime) and not until the first meal the following day (whenever that is). This too allows insulin levels to fall, and enables your body to do all the wonderful “housekeeping tasks” that both Dr. Panda and Dr. Walker write and teach about.
(Note: For those who are metabolically unwell, done with supervision, slightly longer periods of intermittent fasting up to 24 hours may be beneficial for lowering insulin resistance, without loss of muscle mass.)
If you would like more information about the different low carb meal patterns available and which might be best for you as well as implementing times for eating and times not eating, I can help.
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To your good health!
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Panda S, Circadian physiology of metabolism, 2016, Science: 354(6315)