Why Daily Fasting and Not Intermittent Fasting?

Suggesting Daily Fasting as a better way to describe a Short Duration Fast

Why Not?

Due to its popularity, Intermittent Fasting became an umbrella term for a wide range of fasting approaches (see below). Plus I found the term Intermittent especially vague and misleading. Intermittent is an adjective, meaning something occurring at irregular intervals; not continuous or steady. Example: an intermittent rain. Well, most people fast for a consistant number of hours each day.

Daily Fasting

Instead of Intermittent, I prefer the term Daily to describe a fast lasting less than 24 hours that can be repeated daily. It’s a way to visualize mentally Daily Fasting as an Healthy Daily Habit. The effects are coming from your regularity and consistency over a long period of time like any other daily habit or routine. A Daily Fast can last anywhere from 12 hours to 22 hours. By limiting its duration below 22 hours, it clearly differentiates a Daily Fast from a Water Fast usually lasting several days.

Starting with 12 hours: one can make sure to fast as long as he eats. In France, people used to have their breakfast at 8 am, lunch at 1pm and dinner at 8pm (20–8= 12 hours to eat, so a 12 hours fast including the night sleep). That’s a traditional 12 hours fast, that people were doing without knowing that it was beneficial to their health and well being.

Adopting a Daily Fasting Habit of 14 hours by reducing your eating window to 10 hours. Simply by taking your breakfast at 08am to finish your dinner by 6pm, you then secure 14 hours of rest for your digestive system.

You can go one step further by eating twice daily or by eating during daylight so that your eating pattern stays synchronized with the circadian cycle.

I tend to think that using the term Daily instead of Intermittent will help to see this fasting approach as a simple lifestyle habit that you can adopt safely in your everyday life.

Daily Fasting, eating in sync with the circadian cycle

Time to Rest and Recover

Humans are meant to be active (eating, moving, working) during daylight and then at rest (relaxing, recovering, sleeping) during the night. Your digestive system isn’t that different from your muscles and your brain, in that he needs time to rest and recover. As you age, it’s likely that your digestive system will need more recovery time each day. So it’s an healthy daily habit to make sure that you’re at minimum fasting for as long as you’re eating, and even better fasting slightly more time than you’re eating.

As any healthy habit, you have to find what type of Daily Fast works best for you, given your life circumstances and constraints. You can experiment around fast durations to see which one works best for you or even simplify it further by eating only twice a day.

My Daily Fasting

I tend to oscillate between a 14 hours Daily Fast (so eating within 10 hours daily) or Eating twice Daily (breakfast + lunch, not counting hours). Most days, I go for a run around sunrise. I then have a post-run breakfast. My lunch takes place close to 1pm or 2 pm depending of my work, especially if I need time for deep or creative work. If I feel hungry that day, I will have a light dinner before 6pm. I noticed that I recover better from my long trail runs by having a shorter eating window. So after a long run, I tend to simply eat one or twice within a 6 hours window. If I eat only twice, I adjust my hydration with water or infusions to compensate for the water that would have come from eating a third time.

Most Common Terms around Fasting

Intermittent Fasting: broad term used for almost any type of short duration fast below 22 hours as well as alternate day fast.
Alternate Day Fasting: an Intermittent Fasting approach. You fast one day, then eat the next day.
5:2 Fasting: Type of IF. You eat normally for 5 days and fast or limit your calorie intake to 500 calories during 2 days.
IF 16:8: popular type of IF in which you fast for 16 hours and eat within a 8 hours window. Some people get slightly obsessed with this number 8. Let’s not forget, that it is just an abstract number, which likely coincide with lab’s opening hours.
TRE or TRF: Time Restricted Eating — or Feeding. Terms used in most research papers. It’s descriptive but “restricted” is not that positive, not talking about “feeding” that describes the feeding time for mice during experiments. TRE 14:10 means fasting for 14 hours and eating within a tine window of 10 hours.
early TRE: describes an eating window Early in the Day like breakfast + lunch or early dinner. It seems to be the healthiest approach of Daily Fasting, but frankly the least appealing and adopted amongst the population as it lacks of social acceptance by cutting out a popular gathering.
late or “social” TRE: here the eating window happens later in the day. “Social TRE” is likely the most popular approach of IF as well as a good excuse to skip breakfast. Regardless of scientific evidences, it is understandable for most people to keep their dinner as a family or social event and therefore as their main meal of the day.
OMAD: One Meal a DAY is another type of IF. It doesn’t specify when to eat but most people eating once a day, eat at dinner time.
Water Fast or Prolong Fast: indicate a Water only Fast that lasts more than 24 hours, often from 48 hours to 4 / 5 days. Longer water fasts require supervision. Some Fasts protocol are conducted in special clinics and include a vegetable bouillon (Buchinger therapeutic fasting).
Fast Mimicking Diet: a 5-day 800 calorie plant-based diet developed by Dr. Valter Longo to mimics the longevity and health promoting effects of a water only fast (Dr. Valter Longo webpage).