Obesity – Solving the Two-Compartment Problem – Fasting 21

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One of the major mistakes made by the Calories In/ Calories Out (CICO) hypothesis is the presumption that energy is stored in the body as a single compartment. They consider that all foods can be reduced to their caloric equivalent and then stored in a single compartment in the body (Calories In). The body then uses this energy for basal metabolism and exercise (Calories Out).

This model looks something like this:

1CompartmentModel

All energy is stored in that one compartment. However, this model is a complete fabrication. It does not exist. This known mis-understanding has led to general acceptance of the CICO theorem. According to this model, by reducing the amount of calories going in, or increasing the amount going out, you may reduce the amount of body energy stored as fat.

Of course, this Eat Less, Move More (or Caloric Reduction as Primary) strategy has a known success rate of about 1% or a failure rate of roughly 99%. This does not deter any of the medical or nutritional authorities to question the sagacity of their advice, though.

To better understand how energy is stored in the body, it is more accurate to use a two compartment model. Dr. Kieron Rooney’s diagram demonstrates that the body is able to derive energy from 3 sources – glucose (carbs), fat or protein. However, protein is not stored as an energy source and is only used when there is excessive dietary protein after which it is turned to glucose.

So, this leaves two potential fuel sources – glucose and fat – and these are stored in different compartments. Glucose is stored in the liver as glycogen – a molecule that is composed of long chains of sugars. This is easily accessible to the body, but there is a limited amount that is able to be stored. After that threshold is reached, the body stores fat. Think of glycogen like a refrigerator. It is very easy to move food in and out of the fridge, but the storage space is limited.473497631

Body fat is much more difficult to access, but you may store unlimited amounts. Dietary fat is directly added to the body’s fat stores. Excessive carbohydrates are turned into fat by the process known as De Novo Lipogenesis (DNL). Think of body fat as a freezer that you store in your basement – you can store lots of food in the freezer but it is more difficult to get at it compared to the fridge. You can also store more than 1 freezer in the basement if you need more space.

As you eat, the body stores energy. As you don’t eat (fast), the body must take stored energy from the body to burn for fuel. But it does not take equal amount from both compartments (fat and glycogen). Glycogen is burned almost exclusively until it is finished – this can last 24-48 hours of pure fasting.

This is logical since it is much easier for the body to get at the glycogen. Think about it this way. If you buy groceries, you first store it in the fridge. Once it is full, then you start to store it in the freezer. When it comes to taking food out to eat, you start by eating the food in the fridge.

Only after almost the glycogen is already burned for energy does the body turns to its stores of fat. Similarly, only when the food in the fridge is gone do you want to go downstairs to that cold dank basement to get the food in the freezer. It takes more effort. You do not burn equal amounts of glucose and fat. For example, if your glycogen ‘fridge’ is full, you will not use any of your fat in the ‘freezer’. If you need 200 calories of energy to go for a walk, you take that exclusively out of the glycogen with none of the fat being burned.

The two compartments for energy are not burned simultaneously, but sequentially. You need to empty out the fridge before you can start using the food in the freezer. In essence, the body can either burn sugar or fat, but not both. This is controlled partially by insulin, and also directly by the Randle cycle – described in 1963. This is also sometimes called the glucose-fatty acid cycle.

In isolated heart and skeletal muscle cell preparations, Randle and his colleagues were able to show that cells that were using glucose for energy were inhibited from using fat and vice versa without any interference from insulin or other hormones. This biochemical mechanism directly forbids the body from using both fuels at once. You either burn sugar or fat, but not both. You can see from the diagram that using glucose eventually leads to the production of Malonyl-CoA which inhibits the use of fat (LCFA – Long Chain Fatty Acid).2CompartModel

So, why can’t you lose weight using the CICO method? Because it is based on the incorrect idea that all calories are equal. When you store food energy (calories), it is stored as sugar (glycogen) in the ‘fridge’ and fat in the ‘freezer’. But you must burn through the sugar first before you can start burning fat.

So, now you want to lose body fat. The first thing you need to do is clear out the sugar in your refrigerator. However, if you are continually filling up your fridge 3-6 times a day with sugar, then you will never start burning the fat in the freezer. The CICO method ignores the two compartment problem and pretends that all calories are stored equally and burned equally (single compartment), even though this has been known to be false for at least 50 years. This is the equivalent of the standard calorie restricted diet of eating 3-6 meals a day with a relatively high carbohydrate (50-60%) content.

You imagine that since you are filing up the fridge with less glucose, it will eventually empty. However, this does not happen. Why? Because, as you start putting less food in the fridge, your body senses that and starts to get antsy. So, it starts to make you hungry and want to eat more. If you don’t fill it up, it will decrease your metabolism so that it is burning less energy.

What’s the solution? First, you could follow a Low Carb, High Fat (LCHF) diet. By severely restricting the amount of carbohydrates, we keep our glucose fridge empty. Now any energy that must be burned must come out of fat freezer. This essentially turns the two compartment problem into a single compartment problem.

Second, you could try intermittent fasting (IF). Fasting essentially burns through all the stored sugars in the fridge quickly. Will you get hungry? Yes, probably. But if you push through that, your body is forced to burn fat for energy. The metabolism does not slow down because of the compensatory hormonal changes of fasting. After several days, hunger is also suppressed – the mechanism is unknown, but likely related to the ketone production.

The bottom line is this. You can store energy in the form of sugar or fat. In the fasted state – you can either burn sugar or fat for energy, but not both. If you are continually supplying your body with sugar, it will not burn fat.

Fasting provides a very quick way to start burning fat. It provides a solution to the two compartment problem. The reason why the Calorie pundits never understand why their model doesn’t work is because they have fundamentally mis-understood the problem as a single compartment.

Update Jan 28, 2016

I belatedly realized that I forgot to add this section. Actually, it didn’t update, so I thought it was in here but it actually wasn’t. Sorry.

There is one more critical input into the system. How easy is it to get food energy from the freezer? If the freezer is locked away in the basement behind steel gates and barred, then it will be very difficult to get the fat out. What’s the main hormone that controls it? The answer is… insulin. (Actually, insulin is the answer to most of the questions on this blog)

It’s well known that insulin inhibits lipolysis. That’s a fancy way of saying that insulin stops fat burning. Well, that’s normal. Insulin goes up when you eat, so it tells the body to start using the incoming food energy and stop using the fat in the freezer.

So, if your insulin is high from insulin resistance, you may find that your body is not able to get at the fat in the freezer. So, as you lower the incoming calories (Caloric Reduction as Primary strategy – Eat Less) your body is unable to get any fat to burn. So it compensates by reducing caloric expenditure. Hence basal metabolism falls.

If you are 8 years old, your insulin resistance is minimal and fasting insulin is low. That means it’s really easy to get at the fat in the freezer. It’s like the freezer is right beside the fridge. Easy Peasy. So, if you simply reduce calories, your body can easily compensate by getting some fat out of the freezer.

This explains the time dependence of obesity. That is, those that have been obese for a long time have a much, much harder time losing weight. Because their insulin resistance is high causing elevated insulin levels all the time.

2017-10-19T12:58:37+00:00 85 Comments

About the Author:

Dr. Fung is a Toronto based kidney specialist, having graduated from the University of Toronto and finishing his medical specialty at the University of California, Los Angeles in 2001. He is the author of the bestsellers ‘The Obesity Code’ and ‘The Complete Guide to Fasting’. He has pioneered the use of therapeutic fasting for weight loss and type 2 diabetes reversal in his IDM clinic.

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85 Comments on "Obesity – Solving the Two-Compartment Problem – Fasting 21"

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JOhnBoB
Guest

THAT made sense! I can’t wait for the book.

Peter
Guest

I have a question on fasting. If I sip bone broth occasionally during the duration of my fast. Is that still considered as a fast? Thanks so much

BobM
Guest

Dr. Fung allows bone broth during a fast.

Sarah
Guest

I had tried sipping bone broth during a fast. But it only made me hungrier and more difficult to fast. Black coffee however, helps to reduce my hunger pangs v easily.

peter
Guest
The statement below was taken from a blog post from this site. I am just wondering if sipping bone both may activate secretion of GLP-1 and insulin? Also, is there a place on this site or other websites that provides more detailed instructions on doing a fast? Thanks so much “Even non nutritive sweeteners, which have no calories at all, can stimulate the insulin response. Sucralose, when studied in obese human volunteers, raises the insulin level 22% higher than water. The GI tract and the pancreas can detect sugars through taste receptors similar to those in the mouth. This may… Read more »
Carl Davis
Guest
No because the broth has protein particles and fat that will elicit an insulin response. You could still lose weight but it is far better to go with the water fast as after a brief period of 48-72 hours when you burn off your glucose you will have many ketones circulating throughout your body for energy and your hunger will become depressed. Continue the fast until you feel genuine hunger than break the fast. I have found this the most difficult part of the fast so be careful as you could ruin many of the benefits of the fast by… Read more »
jesse
Guest

fat doesN’T stimulate insulin

Walt
Guest

Jesse, it actually does but to a far lessor extent than do simple carbs, complex carbs, and protein. Somewhere Dr Fung did a jpeg on that.

RaceRealist
Guest

The general rule of thumb for breaking your fast is that 50 kcal breaks it.

Barbara
Guest

Dear Dr Jason Fung.

A few days ago I found your site , listened to lectures on yt and I love it!
You will save the lives of many people who have lost hope that recovery is possible.
I am very grateful, thank you very much. Blessings.

Dave
Guest
I’m a little confused. I thought the body used glycogen during anaerobic activity (e.g., sprinting) and a combination of fatty acids and glucose during other activity (e.g., slow jog). When it comes time to make up for a caloric deficit (either under feeding or during fasting) your body can use glycogen (from liver and muscle cells) and can release fat from adipose tissue (provided insulin levels are low) to make up the caloric deficit. Doesn’t the body metabolize fatty acids during exercise while you’re at a fractional level of maximum heart rate? (say, 75% of max heart rate). If you… Read more »
Isabela
Guest

You are not missing anything, you said it yourself: “due to low levels of insulin”. The way it works in normal people is the way you described. However, many people that need to lose fat, have very high levels of insulin. Me included, after many months of LC my insulin is still over the upper “normal” level (which is not normal, as we now know). This high insulin will not let you access the freezer much. This high insulin will make you need to exhaust the glycogen store before slowly turning to the fat store.

Bernard P.
Guest

Isabela, the answer to your problem is *fasting*. Low-carb is not enough, because proteins also stimulate insulin production, along with the lower carbs. You have to starve the body completely to make the insulin lower.
Also, fasting means fasting. Too many people are talking about 14-hour and 16-hour “fasts”, or are finding reasons to eat during fasts.
The best compromise is 24-hour alternate-day day fasting.
As time passes, your body weight will decrease, as fat is burned off. At the same time, insulin sensitivity will improve, as the body benenfits from sustained periods with low insulin levels.

Lyn S
Guest

Bernard, as fasting lowers your insulin levels does that improvement remain long after fasting, do you know

Elena
Guest

Insulin goes up as soon as we eat. For non-diabetics glucose will go down and insulin will follow. For diabetics (insulin resistant) glucose will linger in the bloodstream and insulin will stay high until glucose goes away (long time). Next meal has to be when glucose level is low, otherwise insulin will be high all the time. This is my understanding of diabetics problem.

Petr Judl
Guest
I must say I am confused here as well. I have been a keen follower of Dr. Fung’s writing since I first came across his blog and have high respect for his work. I like how the posts are made simply understandable with analogies used etc. However I am not sure if things were not too oversimplified in this particular post reading statements like: “Dietary fat is directly added to the body’s fat stores.” “Only after almost the glycogen is already burned for energy does the body turns to its stores of fat.” My understanding has been that (especially during… Read more »
Jeff
Guest
“Dietary fat is directly added to the body’s fat stores.” I don’t understand that one either, thought that fat is just a different high density/calorie energy source that will not spike your insulin levels and be absorbed and stored more slowly. “Only after almost the glycogen is already burned for energy does the body turns to its stores of fat.” “My understanding has been that (especially during aerobic activities), the body will use a mixture of both glycogen and fat as source of energy.” My understanding has always been is that glycogen is used first then once depleted the body… Read more »
Rob
Guest
I think one of the answers to these questions is that the body’s store of glycogen in the liver is limited. I read somewhere that on average about 500 calories is stored and once depleted, over a few hours, one gets hungry again and refills the stores. Exercising in a fasted state will mean that the fridge is empty and you begin to get at the stuff in the freezer right away. This fasted state can be as little as 3 or 4 hours especially if you are on a low carb regime. The protein goes to the muscles and… Read more »
PhilT
Guest

I wonder if the fuel mix occurs in separate organs for example muscles running on glycogen with the heart running on fatty acids or similar. At rest I oxidise 70% fat, 15% protein and 15% carbohydrate according to respiration analysis.

Carl Davis
Guest
It is true that the body will access glucose before it will access free-fatty acids. We evolved for hundreds of thousands of years and perhaps millions (2.6) on a virtually no-carbohydrate diet) and our bodies are virtually the same as our paleolithic ancestors. Our bodies evolved using free-fatty acids and ketones as the main source of energy. In essence we have perverted our bodies by consuming grains and starches that provoke and insulin response form our pancreas to sweep out the “poison” that is carbohydrates. As long as insulin is sweeping though the body lipolysis or the burning of fats… Read more »
Zig Euner
Guest

When I started reading this, I thought the two compartments were going to be visceral and subcutaneous fats. I’m glad, however, to learn about this logic mistake CICO rests on.

But I still am curious: is it harder to lose subcutaneous fat than visceral, or is it just me? [By harder, maybe I mean: it takes longer, or the body guards it more jealously (especially in someone like me, who has calorie restricted off and on the last 30 of my 44 years), or something else.]

johnnyv
Guest

Visceral is usually the first to go which is a good thing as it is metabolically more active than subcutaneous.
In general visceral is more vascular and contains a higher % of large adipocytes plus having more glucocorticoid and androgen receptors than subcutaneous.
Meaning it is very much easier for visceral fat to release fatty acids once your insulin is under control.

As subcutaneous is less vascular than visceral and compared to visceral it is much more susceptible to vessel constriction to conserve body temp which can further limit lipolysis.

Kelly
Guest

Excellent news about the visceral fat going first! Apparently, that is the most dangerous type in metabolic syndrome.

LCarb
Guest

I like this analogy. I’m curious though about the very small percentage of people that DO lose weight on a high carb/low calorie diet where they don’t fast and aren’t in ketosis. How you you describe their weight loss with the fridge/freezer analogy. Are they constantly going back/forth between glucose/fat burning? Or are their glycogen stores not filling up and during the long overnight fast is where they are losing fat, a little at a time?

deirdra
Guest

They are mostly part of the 99% or athletes. You can lose weight on many kinds of diets, but 99% gain it back in the long run.

Deb Griffith
Guest

Or are young. Or have the very rare near-perfect metabolism.

Dianne
Guest

Brilliant article Dr Fung, that explains a lot. But does this mean that short fasts (up to 2-3 days) are vastly inferior to longer fasts because the sugar stores (fridge goods) are never totally used up and the body is never really into ketosis and digging into the “basement freezer”? Some people succeed on the 5:2 diet but I am not sure how that can work. Would appreciate your opinion on this, thanks

BobM
Guest

Dianne, I don’t think so, if you’re eating a low carb, high fat diet. You’ll already be burning fat when you begin to fast. I’ve done a few 5-day fasts, a bunch of 3-day fasts, one 2-day fast (just finished this one), and many other types of fasts (typically, I no longer eat breakfast and sometimes don’t eat breakfast or lunch).

Dianne
Guest

BobM, my problem is that although I eat generally LCHF, my grams of carbs are generally more 60 -100g per day. I have big trouble staying ketogenic. When using pee sticks I find I am not in ketosis till day 3 – and although I have achieved a 7 day fast followed by 2 x 2.5 day fasts during this month – I seem to have trouble with massive hunger at the point where ketosis kicks in properly 🙁

Deb Griffith
Guest
I just “left” a group of keto followers, and have practiced some myself here and there. I started last April with 5:2, then 4:3, and added low carb along the way, to achieve a 40 lb loss, and have maintained it. Ketosis , most agree, uses the 20 grams or less carbs per day , depending on the individual. You might be able to eat 50 a day, but it would be rare. And it sounds like not. And when you do find you sweet spot spot, it can take 2-3 days AVERAGE, again, each person is different. The shorter… Read more »
Layne
Guest

I’ve tried IF and it turns me into a raging lunatic. I do not do well. I have read that fasting is different for women because of hormonal differences between men and women.
I have also tried keto (never can get my electrolytes right I think) and plain low carb.
I am on a break from low carb because after three weeks my energy was still very low and my moods. Oh my moods. Very unstable.

So, my question is, what mechanism might be at play that I am unable to do even low carb without disastrous effects?

Thanks!

Lucylaw
Guest
This has been my experience with fasting and lchf….I am also a woman….for the first few months of using a ketogenic diet, I did not fast, but I was pretty darn faithful to my program (<20g carbs). I lost 40 lbs that way, but eventually hit a stall. That's when I added IF and some high intensity interval training. The fasting was not difficult, other than thinking I should be hungry. I fast regularly now, looking forward to brain health, body health, regenerated cellular health. Anyway, the point I'm taking forever to get to is this: If intermittent fasting is… Read more »
Vytas
Guest

This is the clearest explanation of this I’ve ever seen. Thanks for this!

Would fasting lead to adrenaline rushes at night and difficulty sleeping as a result? Also, what do you when you’re fasting and need to take medications, vitamins or supplements that require being taken with food?

Kelly
Guest
Great article. Well put and I can see it demonstrated in my own body over and over after a year of IF/zero-carb. I am surprised by this phrase: “If you don’t fill it up, it will decrease your metabolism so that it is burning less energy.” A few months ago I thought you had a blog that adamantly went against the theory of slower metabolism? But I believe it to be true. My ultimate question is “Why decreased metabolism when cutting glucose?” I’ve noticed this in myself. If I try to eat limited carbs in my diet or if I… Read more »
karen
Guest

Thanks Kelly for posting your comment. My husband is diabetes 2 and we do high protein/fat with occasional carb cheats…? but he’s been having a lot of “zombie fatigues” in the past 8 mo and maybe the carbs are doing it. Also wondering how Splenda affects him. He has SO much in his coffee or probiotic lemonade. Trying to get him on Stevia…slowly. Thx
But wondering… You just don’t do any carbs? How does one do that? Also do you not feel faint when you fast?

Jo tB
Guest
Karen, in my experience as a T2D, my body treats artificial sweeteners the same way it does pure sugar. My BS goes balistic. Even Stevia has the same effect. I found out by metering before and after taking the sweetener. Has your husband ever done that? Your body can’t tell the difference: sweet is sweet, from whichever source it comes. It’s the taste buds on the tongue that feels that something sweet (carbs) is enterig the body and that causes an insulin rush to occur (fine if you’re healthy, not if you’re a T2D). If he is trying to control… Read more »
Silver
Guest

I think artificial sweeteners also raise my insulin levels. That would explain why drinking diet soda makes fasting insufferable. I can fast without issues for days, but as soon as I drink a diet coke, an hour later I start feeling sluggish and very hungry (even though hunger was near nonexistent just an hour before). I guess it has something to do with the pancreas reacting to flavor? It makes sense too, cause increased insulin lowers my blood sugar way down, not knowing there is no actual glucose being added to my blood circulation, and that increases hunger.

Kelly
Guest
Hi, Karen. Sorry I never saw this comment from you. Yes, after fighting with my weight and always being 25-50 lbs over weight and walking around with 110-140 blood sugar levels, I realized I was ready to doing something different (even things very against the norm). This is how I got to zero-carb. There are a few Facebook groups and a subreddit with people that practice this lifestyle. It was a bit tough in the beginning. I pretty much have cut out all vegetables and all dairy, mostly as an experiment. But after 4 weeks I was completely convinced this… Read more »
Kelly
Guest

Karen, I have found that switching from coffee with Splenda to tea with lemon and no sweetner is a lovely way to boost energy and lower BG ( i also have T2D). Plus, saves a bunch of money with the cost of coffee and splenda being so high! 🙂

Kelly
Guest

OMG… Kelly and I aren’t differentiated in this thread!! How to do that?

Jack
Guest

I get really confused about muscle loss in all of this.

I went low carb while marathon training and ended up losing 4 lbs of muscle. It seems I have to eat carbs but if I want to lose weight I can’t. There must be a way to do this without wasting muscle.

I have been just eating carbs before and after my workouts and I lost some weight but I’ve been stuck now for 3 weeks and just can. Drop any more. I’m scared to drop more carbs for fear that I will just lose muscle.

Sascha
Guest
Just my personal unprofessional thoughts about this (i ran a couple of marathons myself if that’s worth anything): 1.) Doesn’t it seem odd to you that as a marathon-runner – which is only a very small subset of the population – you even have to struggle with weight-loss? Most people can’t do a 5k at the speed you do 42k and some don’t have that struggle at all. 2.) What you consider low-carb might not be low enough to make the switch. If you lower the carbs but don’t go low enough you starve yourself instead of “going to the… Read more »
Laurent
Guest

How sure you losing muscles? It’s more certainly water and glycogen stored in the muscles.

Anderson
Guest

@Jack

I have the same problem of muscle loss during fasting & end of fasting week. I am also confused on how to regain lost muscle mass as it may jeopardise the efforts to combat insulin resistance if I increase caloric intake with protein. We request Dr.Fung to guide us meantime if any other member has any insight please post your experiences & suggestions.

Madeline Winter
Guest
Thanks for the incisive article. I have been struggling with a ketogenic diet for six months. I have not lost a single pound. Sometimes, I would loose a few, but then regain them inexplicably. I was taking a lot of fat in the form of coconut oil and butter, moderate protein and very low carb, often under 10 grams. I hear of other women in the same situation. This article makes clear what I have often suspected, that I am just never tapping into my fat stores. I have been working towards longer and longer fasting periods, which seems to… Read more »
Mike
Guest
Wood
Guest

With all this YOu say it is impossible to lose fat on a moderate fat and carb diet eating 6 meals a day like all the bodybuilder (even natural) do who almost never use fasting because the fear of losing muscle, or vegetarians who eat 500+ gramm ch per day… Or I misunderstood something…

Peter
Guest

Is there a place on this site or other websites that provides more detailed instructions on doing a fast? Thanks so much

Aaron
Guest

+1

Filippo B.
Guest

then what about respiratory quotient?Is it a lie all?What about that maraton man at 42 km go against the wall because he finished all glicolit energy and the fatty acid don’t to be used whitout these.To me the fisiologys have taught that fat fire at the flame of the carbohydrates.This combination is less efficient in principiant and than this improves whit advance of training

allison G
Guest
OK I have been “fasting” for about 8 mons. I do an eighteen fast for 5 days a week with a few 22-24 hr thrown in when I can. Is this good enough or do I have to fast for a longer time. When I do eat it is always low carb so I have maintained a 42 lb weight loss but have stopped loosing. After more research now I have found out that the stevia in my black coffee has not been a true fast? So in order to loose more weight and to help my BS would my… Read more »
Martin Williams
Guest
Alison, here is the opinion of a nobody. I have found it necessary to count calories on a alternate-day protocol. If I follow Krista Varady’s pattern, i.e., 500-600 calories (from any source, including junk food) on a ‘fasting’ day, and ad libitum eating on an eating day, then I don’t lose. My efforts are seriously compromised by the amount of alcohol I drink. But even if I remove that for a period, I still have to count calories. The way I think of it is this: Even if everything the advocates of LCHF say is bullshit, then fasting is still… Read more »
Dev
Guest
@ Allison I am in very similar situation like you.I eat one meal a day i.e. every day at 7.30 PM. I drink coffee with cream an cinnamon without any sweetener. I have lost 40 pounds and just cant go further.I came across an interesting explanation i.e. Set Point Weight Theory which explains as under : According to the set-point theory, there is a control system built into every person dictating how much fat he or she should carry – a kind of thermostat for body fat. Some individuals have a high setting, others have a low one. According to… Read more »
Karen
Guest
Thank you, Dr Fung, for this and the many other interesting and helpful posts. I made a request to my public library to purchase your book, and I am the first on the reading list when it is available in March! I am currently eating according to the 5:2 approach. In addition to LCHF, I have had good luck in the past with doing a 3 to 5 day “fat fast”, i.e., 1,000 to 1,200 calories of 90% calories from fat. (I did this for about a year, once every three or four months.) For me, a fat fast acts… Read more »
Jo tB
Guest

Karen, What do you eat when you are on your “fat fast” days. I would love to know.

Karen
Guest

Jo, I eat healthy fats, especially avocado, walnuts, flax meal, olives and olive oil, and hemp seeds. Dana Carpender has a small book called “Fat Fast” with 50 recipes that are helpful. But that said, I find that it is much harder to eat this way, even for just a couple of days, than it is to simply fast for two days a week and then eat LCHF most days.

james proffitt
Guest

This is not meant as a challenge but stems from confusion. How can the very obese lose massive body fat on juice fasts or otherwise consuming copious fruits?

Ryan
Guest

The Calorie Reduction method technically works so only getting a couple hundred calories a day in juice will let you lose weight, the problem is the sugars in the fruit keep your body producing insulin meaning you get all the downsides of the traditional diet like constant hunger, mood swings, and your body set weight doesn’t actually change so you put the pounds back on easily.

Jerry kahn
Guest
Two connected questions. Some authorities claim that on the fasting day a limit of 500 calories or one-fifth daily intake will work. In support of this, you have in a video on Larry his wife having success on a short-term fast of about 18 hours instead of the full alternate day fasting. (both are obese and Larry has type-2 diabetes). Second question, in your examples (video on diabetes cured with diet) of bariatric surgery, there is a cure rate for type-2 diabetes of between 80 and 90%; and most are cured or nearly cured within two weeks. I assume that… Read more »
Belle
Guest

Rather a luxury problem soved….
In March 2013 my husband invited me to a cruise. Wow wonderful but….my dressy clothes didn’t fit anymore and I didn’t want t o buy a bigger size for this occasion, so…I HAD to lose weight!
Google gave the solution and I found Zoe Harcombe and dietdoctor.
Three months later I fitted in my long skirt and “old” cocktail dresses.
I lost 7 kilos in total and now, three years later my weight is still 52 kilos, slimmer than ever!. And lowcarb is our lifestyle…
Not bad for an 80 year old!
If I can do it, you can do it!

Steve
Guest

Another very clear and informative article. Many thanks, Dr. Fung.

Anna
Guest

Hi to all,
I’m trying to understand, while on LCHF routine, what factor determents –
when to burn body fat and when to burn fat that comes from food?
As it seems to me, if the fat consumption is regular, there’s no reason to get to the “basement” for energy.
What am I missing?

Elena
Guest

I think this is the point of fasting: to make sure no fat is coming in, so the “basement” (stored) fat has to be used as energy provider

Bernard P.
Guest

From the 6th paragraph of this post:

“Dietary fat is directly added to the body’s fat stores.”

Dr. Fung, I’m confused about this. Is it as simple as that? After watching and reading everything on this web site, I was under the impression that eating fat is not fattening per se. This sentence is raising questions in my mind about the manner in which fat is metabolized.

Maybe you could write a post about the metabolism of dietary fat?

Sarah
Guest

Actually even I have the same doubt.. All this while, I thought dietary fat doesn’t make me fat. Only insulin does that.

Lucylaw
Guest

Let’s not forget, if the total energy expenditure (TEE) your body needs for the day is 2400 k/calories, then you can’t expect to eat 3,600 calories of fat per day and lose weight…. Right?

claudio
Guest

hi, I lately read a paper “Kevin Hall -Calorie for calorie, dietary fat restriction risult in more body fat loss…” CelMet 22-3 sept 2015 that seems to disagree with insulin hypothesis. What do you think about ?

Korovev
Guest
Dr. Fung, this entire website is very illuminating. Congratulations for the great work. Have been hearing about the role of carbohydrates and insulin in obesity for a long time, but never in such a rigorous and systematic way. I am however still confused about two aspects of the theory presented and would appreciate if you could clarify them: 1) Let’s say an obese, insulin-resistant subject with an estimated RMR of 2000kcal starts an LCHF diet. For the sake of simplicity, let’s say he eats at his RMR – 2000 calories – hypothetically at 100% Fat. At this level of calories… Read more »
Korovev
Guest

The first point was probably not clearly expressed.
The tie-in would be the concept of ‘weight set-point’. However how this re-set could happen (assuming it is possible?) it is not clear to me.
Regular exercise? Long-term IF/LCHF? Both?

Elena
Guest

I am wondering if eating only when BG is lower than personal A1C (average BG), and eating Low Carb so the glucose does not go high again and insulin too (basically eating from the low insulin index foods) would lower in time the Weight Set Point. Theoretically this method will continuously lower A1C through fast (eating only one has low BG) and low carb.

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[…] Original Article by Jason Fung @  IntensiveDietaryManagement.com  […]

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[…] As mentioned before, short term storage of food energy (glycogen) is like a refrigerator. The food energy goes in and out easily, but there is limited storage. Long term storage (fat) is like a freezer. Food is harder to get to, but you can store much more of it. If you eat 3 times a day, it’s like you go shopping for food 3 times a day and any leftovers get stored in the fridge. If there is too much for the fridge, it goes into the freezer. […]

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[…] As mentioned before, short term storage of food energy (glycogen) is like a refrigerator. The food energy goes in and out easily, but there is limited storage. Long term storage (fat) is like a freezer. Food is harder to get to, but you can store much more of it. If you eat 3 times a day, it’s like you go shopping for food 3 times a day and any leftovers get stored in the fridge. If there is too much for the fridge, it goes into the freezer. […]

Jen
Guest
A few years ago I gave up bread, flour, pasta, rice, potatoes and so on. No weight loss. Then I gave up sugar, pies, cakes, sweets, candy. No weight loss. Then I discovered the Keto diet and I lost 15lbs before hitting a plateau. Mind you I never left Obesity. Now I have discovered Keto and fasting and I am dumb founded no weight loss. I did however getting my FBS from 105 down to 95 each morning. I am a menopausal 5’1 female and weigh 165 and feel I will always weigh 165. I have not been able to… Read more »
Dave
Guest
I recently did a 5-day liquid-only fast. I started on a Sunday evening at about 7-pm (my last meal) and had nothing but water, coffee (usually black, but sometimes with heavy cream or a little half-n-half), and tea till the following Friday evening. That Friday, to break my fast, I had a cup of hot chicken broth about 30-mins or an hour before having a couple of fried eggs. I had no problems getting back on track with my low carb, high fat, moderate protein (LCHFmP) way of eating after that. Before starting my fast I, too, wondered if I… Read more »
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[…] let’s think about this problem in the context of the 2 compartment model of obesity that we have used before. There are two compartments for body energy. We take calories in as food. This gets stored in the […]

MLB
Guest

What do you think of the Lemonade Cleanse?

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[…] can either burn fat, or burn sugar. These two fuel systems are separate and do not interact (see Randle Cycle for more details). When insulin levels are high, then the body runs on glucose. During that period, […]

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[…] can either burn fat, or burn sugar. These two fuel systems are separate and do not interact (see Randle Cycle for more details). When insulin levels are high, then the body runs on glucose. During that period, […]

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[…] can either burn fat, or burn sugar. These two fuel systems are separate and do not interact (see Randle Cycle for more details). When insulin levels are high, then the body runs on glucose. During that period, […]

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[…] Intensive Dietary Management. (2016, jan). Obesity – Solving the Two-Compartment Problem – Fasting 21. Hämtad 2016-07-20 från https://intensivedietarymanagement.com/obesity-solving-the-two-compartment-problem/ […]

McGregor
Guest

It makes a lot of sense. However, why did I lose more than 30 pounds with calories in/out method? Not saying fasting doesn’t make sense, I just don’t understand why discrediting the method if it worked for me. I am sure I am missing something.

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[…] has a 1% success rate and a 99% failure rate according to Jason Fung’s article entitled “Obesity – Solving the Two-Compartment Problem – Fasting 21”. Furthermore Fung states another mistake made is the “Calories In / Calories Out (CICO) […]

James
Guest

“But you must burn through the sugar first before you can start burning fat.” As a simplistic explanation this makes a lot of sense, but if taken literally, it’s obviously false. Blood sugar drops to 0 before any fat oxidation kicks in? You’d die first. Clearly it’s not a step function as this quoted sentence implies. It must be a sigmoidal function, but the shape parameter (Hill coefficient) governing it would be really interesting to know, and even more, what factors affect the shape parameter?

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