"Breakfast of champions.
" What’s the difference between eating lessfood and eating no food? Well, Let’s look at two different situations.
…In 1944, a study called the Minnesota StarvationExperiment was conducted and was designed to understand the effects of caloric restrictionon the body in order to gain some knowledge that would help people starving in the aftermathof World War 2.
Thirty-six healthy men with an average heightof 178cm (about five foot ten) and average weight of 69.
3 kilograms (or 153 pounds) wereselected.
For three months, they ate a diet of 3200calories per day.
Then, for six months they ate only 1570 calories.
However, caloric intake was adjusted to attemptto have the men lose 1.
1 kilograms per week, meaning some men got less than 1000 caloriesper day.
The foods given were high in carbohydrates-things like potatoes, turnips, bread and macaroni.
Meat and dairy products were rarely given.
During the six months, the men experiencedprofound physical and psychological changes.
Everyone complained that they were too cold.
One subject talked about having to wear asweater in July on a sunny day.
The subjects’ body temperature dropped toan average of 95.
8 degrees Fahrenheit (35.
4 degrees celsius).
Physical endurance dropped by half, and strengthshowed a 21 percent decrease.
The men experienced a complete lack of interestin everything except for food, which they were obsessed with.
They were plagued with constant and intensehunger.
There were several cases of neurotic behaviorlike hoarding cookbooks and utensils.
Two participants had to be cut from the experimentbecause they admitted to stealing and eating several raw turnips and taking scraps of foodfrom garbage cans.
At first, the participants were allowed tochew gum, until some of the men began chewing up to 40 packages a day.
Now compare all this to the case of AngusBarbieri, a Scottish man who in 1965 fasted for over 380 days straight.
That is he took in no food whatsoever -nothingbut water, black coffee and straight tea for just over a year.
He lost 276 pounds, going from from 456 poundsto 180.
A case report published by the Dundee UniversityDepartment of Medicine in 1973 said “.
The patient remained symptom-free, felt well andwalked about normally,” and “Prolonged fasting in this patient had no ill-effects.
” There were no complaints of mind numbing hungerand he kept the weight off- for several years his weight stayed around 196 pounds.
This of course is not a perfect comparison,with the case of Angus, there’s only one subject and his starting weight was drasticallyhigher compared to those in the Minnesota Experiment.
However, it does illustrate some very interestingpoints about just how different of a physiological response you get from fasting (that is, eatingnothing) compared to eating less, or caloric restriction.
Dr.
Jason Fung, a Toronto physician specializingin kidney disease, and author of the Obesity Code, says that compared to fasting, CaloricReduction will result in: less weight loss, more lean mass loss (i.
E.
more muscle loss),and more hunger.
Let’s start by talking about hunger.
In Upton Sinclair’s 1911 book “The FastingCure,” he writes about fasting as a means to improve health.
In describing his first couple attempts atfasting he writes “I was very hungry for the first day-the unwholesome, ravening sortof hunger that all dyspeptics know.
I had a little hunger the second morning,and thereafter, to my great astonishment, no hunger whatever-no more interest in foodthan if I had ever known the taste of it.
” Sinclair recommends to do quite long fasts- around 12 days or so.
In a section addressing concerns about fastinghe writes “Several people have asked me if it would not be better for them to eatvery lightly instead of fasting, or to content themselves with fasts of two or three daysat frequent intervals.
My reply to that is that I find it very muchharder to do that, because all the trouble in the fast occurs during the first two orthree days.
It is during those days that you are hungry.
” Then he says: “.
Perhaps, it might be agood thing to eat very lightly of fruit, instead of taking an absolute fast-the only troubleis that I cannot do it.
Again and again I have tried, but always withthe same result: the light meals are just enough to keep me ravenously hungry.
” In the book he says you will know when youshould finish fasting, because your hunger will “return.
” He quotes a letter he received from a 72 yearold man saying “After fasting twenty-eight days I began to be hungry, and broke my fastwith a little grape juice, followed the next day with tomatoes, and later with vegetablesoup.
” He quotes several other letters he receivedfrom readers and this disappearance and reappearance of hunger is a common theme.
Everyone who wrote to him fasted for at least10 days, saying they only broke their fast when hunger “returned.
” This phenomenon runs contrary to the ideaone would get hungrier and hungrier as long as they don’t eat.
However, most people have experienced forthemselves that this is not the case.
Some will find that they are not hungry atall in the morning or at least they are not as hungry as they are for lunch or dinner.
But unless you are eating in your sleep, themorning is when you have gone the longest without food.
Some of this can be explained by the hormoneGhrelin.
Ghrelin, known as the “hunger hormone”has been found to increase appetite and weight gain.
A study at the Medical University of Viennalooked at patients participating in a 33 hour fast.
Their ghrelin levels were checked every 20minutes.
Here’s how the levels changed over time.
What’s interesting is ghrelin is lowestat 9:00AM, which is when they have gone the longest without eating.
And, Ghrelin comes in waves and overall doesn’trise during the period the subjects were fasting.
Then, As you can see, ghrelin rises in syncwith normal lunch and dinner times, as if the body had learned to expect food at thattime.
However, that ghrelin rise spontaneously decreasesafter 2 hours without food.
I’ve experienced this kind of spontaneousdecrease in hunger myself many times when I was working as a consultant.
Lunch time would come and I would be hungry,but I was too busy to eat so I just kept working.
Pretty quickly I forgot about eating and wasn’tparticularly hungry until dinner time.
This is very helpful to keep in mind if you’redoing a long fast or even if you’re starting intermittent fasting - you’re going to getannoying waves of hunger, especially around the times that you usually eat.
But, it won’t get worse, the hunger willsimply go away if you are patient.
Another study concerning ghrelin was doneat Aarhus University Hospital in Denmark and it shows what happens if you do a longer fast.
They looked at the ghrelin levels of 33 subjectswho fasted for 84 hours.
So, did they get increasingly hungrier throughoutthe fasting period? Well, No.
Their ghrelin followed similar rhythms eachday but actually decreased the longer they fasted.
Going longer without food actually made themless hungry.
This gives credence to what Upton Sinclairand his readers said about hunger disappearing after the first 3 days of fasting.
I’ve done a couple 5 and 6 day fasts inthe past myself and this was indeed the case.
Actually, I did a 4 day fast last week andagain the 4th day was when I had the least hunger.
Another thing that may be contributing tothis phenomenon is that you are entering ketosis.
Ketosis is a physiological state where yourmetabolism switches to using primarily fat for energy.
For this reason ketosis is popular as a weightloss method, but it has many other benefits including better physical and mental efficiency.
Ketosis occurs when you restrict carbohydratesdown to 50 grams or less and you don’t eat too much protein.
Everyone’s body is a bit different so youmight have to eat even less carbohydrate or may have room for more, but the recommendedratio of a ketogenic diet is to get 5% of your calories from carbs, 25% from proteinand 75% from good fat.
A simpler way to enter ketosis is just don’teat anything for a long enough time.
This is one of the major points in the differencebetween fasting and caloric restriction.
The problem with the subjects in the MinnesotaStarvation experiment was that they were eating just enough to keep them out ketosis and keeptheir metabolism primed for burning carbohydrate (glucose), so they couldn’t use their bodyfat for energy.
This explains a lot of things like why theywere losing their strength and were very sluggish and cold.
It also clears up why Upton Sinclair saidfruit or light meals were just enough to keep him ravenously hungry and far weaker thanif he had just eaten nothing.
As I explained in my last video, insulin isnecessary for glucose to get into the cell to be used for energy.
When you eat carbohydrates, the pancreas secretesinsulin to deal with it and too much insulin hampers the action of something called hormonesensitive lipase which is necessary to mobilize fat and use it for fuel.
Though, keep in mind that grains or refinedcarbohydrates will provoke a much higher insulin response than say green vegetables.
Now because the body is having a hard timeusing its fat for fuel, it will do a couple things: One, it will simply slow down metabolismto preserve energy.
In the Minnesota Starvation experiment, thesubjects metabolism dropped by 40 percent.
Their bodies didn’t have access to its storedenergy, and their restricted calorie diets don’t provide much fuel so there’s nochoice but to slow down the metabolism.
Ironically, in the case of fasting, as JasonFung points out - metabolism actually goes up.
"If you don't do anything about your insulinand just reduce your calories, your metabolism goes down.
But what happens during fasting? Well, here's a study of 4 consecutive daysof fasting.
What happens to your REE - this is this middleline here, that's the resting energy expenditure.
It doesn't go down, it goes up.
You're burning more energy than you did.
" The other thing the body will do when it can’tuse fat for fuel is break down muscle into glucose through a process called gluconeogenesis.
The body doesn’t want do this too much becauseit’s not very smart to completely eat through something as important as muscle, but whenit can’t access its own stored energy it’s more likely to resort to this.
This is why you’ll experience more muscleloss on caloric restriction than if you ate nothing.
When you are fasting, Human Growth Hormoneis released.
As the name implies, Human Growth Hormoneis an anabolic hormone - a hormone conducive to growth.
In Leningher’s Principles of Biochemistrytextbook they give the example of how injecting the human growth hormone gene into a mousemakes it unusually large.
As explained in Guyton’s Textbook of MedicalPhysiology: ".
Growth hormone also mobilizes large quantities of free fatty acids fromthe adipose tissue, and these in turn are used to supply most of the energy for thebody cells, thus acting as a potent "protein sparer.
" "That is human growth hormone is protectingyour muscles from breaking down.
The study I referred to earlier about subjectsundergoing an 84 hour fast shows that growth hormone rises significantly after the secondday of fasting.
As mentioned earlier, you should enter ketosissometime within the first 3 days or so of fasting, and it depends on how much you aremoving around and what your diet was like before starting the fast.
The state of ketosis is a great indicatorthat your body is making good use of its stored body fat for energy.
In Tim Ferriss’ book “Tools of Titans,”Tim talks about his first clinically supervised 7 day fast.
For some sort of liability reasons, he wasn’tallowed to exercise or leave the facility.
Considering exercise is a potent stimulatorof human growth hormone and will help deplete glucose stores, not getting any exercise isa great way to prevent yourself from getting into ketosis during a fast.
It’s also a great way to lose muscle.
Tim says he lost 12 pounds of muscle duringthe overly restrictive clinically supervised 7 day fast.
But, when following a protocol designed toget him into ketosis as soon as possible - involving things like 4 hours of brisk walking, he dida ten day fast and apparently lost zero muscle mass.
One last factor in Ketosis preserving muscleis leucine.
When you're in ketosis, you have a higherfasting blood leucine level.
And leucine is a key branch chain amino acidthat has an anabolic effect on the body so it preserves lean body mass.
A lot of people interested in building musclemay be worried that fasting or a ketogenic diet wouldn’t work for them because insulinand therefore carbohydrates are necessary for protein synthesis (i.
E.
muscle growth),but actually this leucine fills that role and is a good trigger for protein synthesis.
So, just to sum all this up: compared to aconventional calorie restricted diet, fasting means you lose more weight in the form offat, you keep more muscle, you have more energy, and you are less hungry.
If proper weightloss is your goal, it might be better to eat nothing at all rather than eating a conventionallow calorie diet.
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