I’ve spent quite a lot of time researching the issue of “Fasting”, and during my studies, I came across the website and YouTube videos of Dr. Jason Fung M.D. in which he shares his comprehensive views about fasting, as well as related issues.

Here at DietHobby my own one-size-does-not-fit-all position is consistently threaded throughout this entire website; and as Dr. Fung shares his preferences and recommendations about food and ways of eating, he makes it clear that he also holds a one-size-does-not-fit-all philosophy.

In his answer to the question: “Why Can’t I Lose Weight”, Dr. Fung says:

“The answer really lies in the multi-factorial nature of obesity.”

“The key to understanding obesity is that many different things can contribute to the development and the treatment. Consider the analogy of your car not starting. There could be multiple problems. For example, the battery is dead, the car ran out of gas, or the spark plugs are worn out. So, if your problem is that the battery is dead, filling up with gas will not help. Neither will replacing the spark plugs. That seems kind of obvious.

But then, websites proliferate about how changing batteries is the cure for cars that don’t start. It is filled with testimonials of how people changed batteries and their cars effortlessly started. Other people attack the website saying that they changed batteries and nothing happened. Instead, they filled up with gas and the car started, so obviously, the key to starting the car is filling up on gas.

That’s exactly what happens in the sad sack, wacky world of weight loss. When you try to lose weight, people assume that there is only one problem for everybody. If your problem is insulin resistance, then reducing carbs may not be the best strategy (intermittent fasting may work better). If your problem is sleep deprivation/ stress, then increasing fibre is not going to be too good.

Cutting sugar works well for those people whose problem is excessive sugar intake. They write books and websites about how sugar is the devil. Others think that is ridiculous and think that refined grains (wheat) is the real devil since they’ve done well reducing grains. Others think that stress relief is the major problem in weight loss. Others blame calories. They all ridicule each other and fill the internet with testimonials. Worse, they all start bickering about how the real problem is carbs, or sugar, or wheat, or calories, or stress, or sleep deprivation, or fibre, or animal proteins etc.

You must understand that they can all be correct. Obesity is not a single problem. There is no single solution. A low sugar diet works amazingly for some, and not at all for others. Just as replacing the battery will work for some cars amazingly and not at all for others.”

For more of this article see Why Can’t I Lose Weight - HTLW12.

Dr. Fung’s website: Intensive Dietary Management, contains a great deal of comprehensive and interesting information which includes an excellent series of articles about Fasting.   Below are links which will take you directly to these fasting articles.

Fasting – A History Part I

Fasting Physiology – Part II

Fasting and Growth Hormone Physiology – Part 3

Fasting and Lipolysis – Part 4

Fasting Myths – Part 5

Fasting Regimens – Part 6

Longer Fasting Regimens – Part 7

The Ancient Secret of Weight Loss – Fasting Part 8

Caloric Reduction vs Fasting – Part 9

Women and Fasting – Part 10

Feasts and Fasts – The Cycle of Life – Fasting part 11

Practical Fasting Tips – Part 12

More Practical Fasting Tips – part 13

The Fasting ‘Advantage’ – Part 14

Fasting and Muscle Mass – Fasting Part 15

Fasting Cures Type 2 Diabetes – T2D 4

Fasting Lowers Cholesterol – Fasting Part 16

Fasting and Hunger – Fasting Part 17

Cephalic Phase Response and Hunger – Fasting 18

Bariatrics is Surgically Enforced Fasting - T2D 6

Circadian Rhythms - Fasting 19

Refeeding syndromes – Fasting 20

Obesity – Solving the Two-Compartment Problem – Fasting 21

The Biggest Loser Diet – Eat Less Move More’s Bigger Badass Brother – Fasting 22

Fasting and Exercise – Fasting 23

Fasting and Brain Function – Fasting 24

Fasting and Autophagy – Fasting 25

Power: Fasting vs. Low Carb – Fasting 26

The difference between calorie restriction and fasting – Fasting 27

Why You're Always Hungry – Fasting 28

Fasting and Ghrelin - Fasting 29

Below is a comment by Dr. Jason Fung recently posted in Fung Schweigh, a private Facebook fasting support group.

"First, there is no optimal way to fast. If you do take tea, coffee and broth and have good results, then that is all that matters. If you only get good results with water only, then do water only. There are others that also use sweeteners and bouillon and do well - so great. However, I don't really like the use of artificial chemicals, so i generally do not recommend. There is no 'right' way. Second, I don't think it is necessary to restrict salt during fasting. Third, we help many people with fasting, but they do not get through without problems. We simply try to anticipate the problems (headache, constipation, hunger, cramps) and manage them through it by reassuring them it is normal and giving tips just as this group does."
 

Information about Dr Jason Fung’s Medical Background:
Dr. Fung grew up in Toronto, Ontario, Canada. He went to the University of Toronto at age 17 to begin studies in Biochemistry. By age 23, he completed medical school at the University of Toronto, and began his Internal Medicine residency there.

Finishing his specialty of Internal Medicine, he studied Nephrology (kidney disease) at the University of California, Los Angeles mostly at Cedars-Sinai Hospital and the VA Wadsworth.  He returned to Toronto in 2001 to start his career in Nephrology, where he still has both an office and hospital practice.

NOTE: 
This is an updated version of an article that I first posted in October 2015.
As new fasting articles by Dr. Fung are becoming available, I am adding those new links and bumping this article up in my blog to make it easy find in DietHobby, under the headings: BLOG CATEGORIES, Fasting. 

NOTE: December 1, 2017 update: 

For the past several years, I’ve followed Dr. Fung’s blog, videos, podcasts and purchased and read his book “Obesity Code”, and his subsequent book on fasting which was co-authored with long-time-low-carb-blogger, Jimmy Moore, … who appears to now be at least 50 to 75 pounds heavier AFTER experimenting with Fung-related Fasting than he was immediately prior to doing so. (See the recent photo posted on the right side of this page.) 

Moore is a severely-obese, very large man who BEFORE he began the fasting experiments ... was claiming an on-going, long-term maintenance of about one-half of a 180 pound weight-loss down from a 2004 highest weight of 410 pounds. Recent pictures show that his current body size now appears to be equal-to-or-larger-than the 410 pound body size which is shown in his posted 2004 "Before" pictures.

It seems clear to me that Dr. Fung and I have read and digested much of the same writings and research.  He is a nephrologist who is holding himself out as a obesity specialist and diabetologist … without any formal training in either of these medical disciplines.

During the past several years Dr. Fung has been heavily promoted by low-carb community bloggers, including Jimmy Moore and a Swedish family doctor, Andreas Eenfeldt, and as a result, has become famous in the low-carb community. 

While Dr. Fung’s fame has increased, his credibility has diminished.  He appears to have lost much of his previous “one-size-fits-all” attitude, and has been becoming more and more dogmatic about his own non-evidence based opinions … many of which appear to be merely wishful thinking.

The way that Dr. Fung ridicules medical experts who disagree with him on any position is frankly offensive, and I find his silent refusal to respond with explanations about questionable opinions to be troublesome. 

I recently read an informed, creative blogger refer to some of Dr. Fung’s questionable statements as “Fung POOP” (Pulled Out of his Posterior).  Unfortunately, at this time, I agree with that assessment, and until I see evidence to the contrary, I will not be linking his future fasting articles here in DietHobby.
 

Today,
I modified the graphics and specifics of my current diet experiment....because I can.  See day-before-yesterday's April 10 blog for the graphics of my previous plan.

The reason for this modification was that when my (Down) Fast day turns into an (Up) Fed day, I need the following day to be a (Down) Fast day.   Otherwise, it seems likely that I'm going to wind up with weeks full of (Up) Fed days. 

At present I'm having too many unsuccessful Fast (Down) days to be able to predict exactly which days will be Fed (Up) days and which days will be Fast (Down) days each week.  So, for a while, it looks like I'll be jumping back and forth between Week 1 & 2 days at random.

See my April 10 blog to see details of my previous plan.

MY CURRENT PLAN:
My UP days are based on my own personal Total Daily Energy Expenditure (TDEE) which is close to 1,000 calories.  Adding 10% brings it up to a total of about 1,100.  My plan calls for 3 weekly UP days.

My DOWN days of about 300 calories are close to ¼ (25%) of my TDEE.  My plan calls for 3 weekly DOWN days.

1,100 plus 300 equals 1,400 divided by 2 equals 700 calories… Therefore a 2 week rotation of this pattern would result in a total Average calorie intake of 700 calories daily.

I have changed my plan to remove the MEDIUM day of about 700 calories from weekly rotation as I have decided to only include it occasionaly.

I am 71 years old, 5'0" tall, and an inactive, reduced obese female (high weight 271 lbs) who has been maintaining a normal BMI for 10+ years, and my individual TDEE of about 1,000 is low, but not “abnormally” low.

For ME, an average daily intake of 700 calories should create a daily deficit of about 300 calories, and … according to the 3,500 calorie rule… result in a weight-loss of about ½ pound per week.

FOR PERSPECTIVE:
To bring my calorie counts into proper perspective...
note that the well-known and frequenlty-used Mifflin formula gives an "AVERAGE" person of my age, size, and activity level, a TDEE of 1150 calories, and a BMR of 985. 

I've been keeping computer records of my calorie intake & weight every day now for about 12 years, and so I know that my own TDEE is about 100 calories or so below the "AVERAGE". 

Women who are younger, taller, heavier, and more active often have very little understanding or knowledge of how low the TDEE is for a short, light, inactive elderly woman... and of course, it is even less for a "reduced obese" one.

For those people who think my TDEE calculation is too low.... HERE's a little personal lesson.
Click this link to get access to one of the online calculators that use Mifflin to determine both BMR & TDEE.  If you are a female use it to run your own numbers. After you've done that .... try changing your own age to 71, and moving yourself to "Inactive"... Look at your numbers change.  Now, change your height to 5'0".... Quite a difference, right?...  Now give yourself ...as an elderly, short, inactive person... a BMI of around 22.5 (which is somewhere near the middle of a "normal"  BMI)  by setting your weight at 115 pounds.... Now, look at the resulting numbers.... which should be around 985 BMR, and 1150 TDEE.

Here is a picture showing my current diet experiment.  I’m using my own Alternate Day Fasting (ADF) eating plan which is based on Dr. Johnson’s Up Day Down Day Diet (JUDDD); and Dr. Varady’s  Every Other Day (EOD) diet; and Dr. Daugirdas’ QOD diet.

Dr. Fung’s blog, (see DietHobby’s RESOURCES, Links for a link to his blog, Intensive Dietary Management) inspired me to do additional experimentation with Intermittent Fasting.

Previously, I’ve written several articles about Intermittent Fasting diet plans here at DietHobby.  You can do a search of DietHobby for them, or you can go to DietHobby’s BLOG CATEGORIES, Fasting to find them. (Look near the middle of the right hand side of this DietHobby page to find the heading: Blog Categories.)

Much of the fasting research that is quoted by Dr. Fung in his blog and new book, The Obesity Code is from Dr. Varady’s research and experimentation of her Every Other Day diet.

The plan alternates “fasting” days with “eating” days.  Dr. Johnson refers to “fasting” days as “Down” days, and “eating” days as “Up” days.  Dr. Varady refers to “fasting” days as “Fast” days, and “eating” days sometimes as “Fed” days and sometimes as “Feast” days.  Dr, Daygurdas refers to the fasting - eating days as “On” and “Off” days.

During UP or FEAST days, total calories are to be a “normal” amount … ideally they will be no more than 10% above an individual’s Total Daily Energy Expenditure (TDEE). 

During DOWN or FAST days, total calories are to be only about 25% of  an individual’s Total Daily Energy Expenditure (TDEE).

For the mythical average woman whose TDEE is 2,000 calories, an UP day would be from 2,000 (up to 2,200) calories; and a DOWN day would be no higher than 500 calories.  Alternating Up days with Down days results in a 2 week pattern of rotation making a 14 day period in which the average calorie intake would be 1250 calories daily ….then repeat, indefinitely.

MY OWN PLAN:
My UP days are based on my own personal Total Daily Energy Expenditure (TDEE) which is close to 1,000 calories.  Adding 10% brings it up to a total of about 1,100.  My plan calls for 3 weekly UP days.

My DOWN days of about 300 calories are close to ¼ (25%) of my TDEE.  My plan calls for 3 weekly DOWN days.

1,100 plus 300 equals 1,400 divided by 2 equals 700 calories… Therefore a 2 week rotation of this pattern would result in a total Average calorie intake of 700 calories daily.

Each week I am including one MEDIUM day of about 700 calories in order to keep every week’s rotation of individual Up & Down days consistent.

My ADF Plan includes two alternatives to my “Basic” plan.  Alternative 1 has 2 consecutive UP days on Saturday & Sunday, and Alternative 2 is has 2 consecutive UP days on Friday and Saturday.  See picture above for details.

I am 71 years old, 5'0" tall, and an inactive, reduced obese female (high weight 271 lbs) who has been maintaining a normal BMI for 10+ years, and my individual TDEE of about 1,000 is low, but not “abnormally” low.

For ME, an average daily intake of 700 calories should create a daily deficit of about 300 calories, and … according to the 3,500 calorie rule… result in a weight-loss of about ½ pound per week.

FOR PERSPECTIVE:
To bring my calorie counts into proper perspective... note that the well-known and often-used  Mifflin formula gives an "AVERAGE" person of my age, size, and activity level, a (RMR) TDEE of 1150 calories, and a BMR of 985.  I've been keeping computer records of my calorie intake & weight every day now for about 12 years, and so I know that my own TDEE is about 100 calories or so below the "AVERAGE".  Women who are younger, taller, heavier, and more active often have very little understanding or knowledge of how low the TDEE is for a short, light, inactive elderly woman... and of course, it is even less for a "reduced obese" one. 

For those people who think my TDEE calculation is too low.... HERE's a little personal lesson. Follow this link to an online calculator that uses Mifflin to determine both BMR & RMR (TDEE).  If you are a female use it to run your own numbers. After you've done that .... try changing your own age to 71, and moving yourself to "Inactive"... Look at your numbers change.  Now, change your height to 5'0".... Quite a difference, right?...  Now give yourself ...as an elderly, short, inactive person... a BMI of around 22.5 (which is somewhere near the middle of a "normal"  BMI)  by setting your weight at 115 pounds.... Now, look at the resulting numbers.... which should be around 985 BMR, and 1150 RMR or TDEE.