Hi all!
There has been much discussion here on whether glycogen can be stored as fat. Curious, I decided to do some research, and I just finished reading this research study on how glycogen is stored as fat.
You can read the study yourselves at the link provided below. But if you’re not inclined, I wrote my own description of the study (very basic description indeed, there is a lot of information unrelated to our question that I didn’t include), and then I followed up with some of the relevant points afterward. I wrote salient points in bold in case you don't have time to read every sentence.
For those of you who aren't inclined to read any further, here's the bottom line: Glycogen CAN be converted to fat, but it has to jump through a lot of interesting hoops to get there.
But please try to read the original study for yourselves, just in case I misread or omitted something. It is not my intention to mislead anyone at all!
Is this the absolute end of this discussion? I doubt it, since this is only one study. But what I found is that is proves everyone right, more or less! LOL
Glycogen storage capacity and de novo lipogenesis during massive carbohydrate overfeeding in man
Kevin JAcheson, PhD; Yves Schutz, PhD; Thierry Bessard, MD; Krishna Anantharaman, PhD;
Jean-Pierre Flail, PhD; and Eric Jaquier, MD
Accessed at: http://www.ajcn.org/content/48/2/240.full.pdf.
A very simple description of the study:
The experiment lasted for 14 day and involved three men all of similar athletic ability and physique. During the first three days, the subjects glycogen stores were depleted to near zero; then from days 4 through 12 (9 days in all), the subjects were overfed on a high-carbohydrate, low-fat diet. Approximately 3600 extra carbohydrate calories per day were needed to produce an overfeeding condition. Subjects also exercised twice a day (30 mins each time) and they could do additional exercise, but they were not allowed to do any anything strenuous (other than the two assigned workouts). It took approximately 4 days for the subjects’ glycogen stores to be filled, but it was after day 2 that glycogen began converting to fat (this was once their glycogen storage sites had reached a minimum level of 500 grams of glycogen). By the end of the overfeeding period (9 days), the three subjects gained on average 4.6 kg. Of that it was calculated that 2.84 kilos was water weight (glycogen requires 2-4 times the amount of water for storage), 665 grams (about 1.5 lbs) was muscle growth, and the remaining 1.1 kilos was fat. Subjects weights returned to their beginning weights two days after the overfeeding period.
Definition: de novo lipogenesis: conversion of glycogen to fat
Here are some of the interesting findings of this study.
1. When overeating on carbs the first thing that is done with the excess glycogen is to fill glycogen storage sites in the muscles and liver.
2. According to the discussion provided in this research, it is pretty hard to fill all glycogen storage sites and then to maintain them. This study showed that muscles can store 800-900 grams of glycogen before becoming saturated. Extremely fit people can store 1 to 1.1 kilos of glycogen. The storage cites have to fill by at least 500 grams before fat synthesis can begin.
3. This study also showed that it is very difficult to maintain a saturated state of the muscles, since the glycogen is constantly being used, and presumably because the average person won’t eat sufficiently of carbs to ever get to saturation. Too, there is our fitness level, which determines how effectively we can fill and maintain our glycogen stores.
4. Interestingly, the subjects in the study spontaneously burned more calories during the 9 days of over-feeding, too; so the scientists had to keep increasing calories to maintain an over-feeding state. On average, test subjects spontaneously burned an extra 840 calories per day, or 35% more calories, during the overfeeding period, presumably due to thermic effect (thermogenesis).Yes, you read that right: A high-carbohydrate diet causes the body to spontaneously burn more calories~up to 35% more calories than a high-fat or high-protein diet.
5. Only once the glycogen stores are filled to at least 500 gram capacity is the remaining glycogen able to be converted to fat. The body is capable of converting up to 500 grams of glycogen to fat per day.
6. But de novo lipogenesis (glycogen to fat storage) doesn’t produce an equivalent amount of fat. That is 1 kg of glycogen doesn’t convert to 1 kg of fat. It converts to much less fat than that. Since it takes about 25% of the glycogen calories to convert it to fat, only some 75% of glycogen excess makes it into fat.
7. Bottom line: Yes, glycogen can be converted to fat (de novo lipogenesis), but it takes a lot of excess for this to occur.
I would love to hear your responses to this study! .........ana xoxo
Tags: I, can, carbs, eating, fat, fruit?, get, glycogen, raw, to
Permalink Reply by Peter David Ebdon on 'Ive received 2 lawsuits in the last 2 days but Im so used to them that they don't take any extra cals to deal with.'
Haha!
Harley, you're different class!
All the best, Peter
Permalink Reply by DURIANRIDER on My bottom line take home message is: Can glycogen get stored as fat? Yes. Can you get fat from those excess carbs? NO FRICKEN WAY! lol!
Its a bit like you can get wind burn and get sore skin but NO WAY are you going to catch on fire! It might feel like it, people might tell you but its physically impossible.
Does anyone know of any physical living examples of either? Exactly. My email is veganbobster@gmail.com if anyone can show me. Please, no Karen Knowler jokes.
Permalink Reply by Michael Clark Christy on 
Permalink Reply by Ana on Yeah, Michael. Their output was monitored in an oxygen chamber and they were deliberately overfed calories in excess of usage~if I remember correctly 3600 calories or more per day. Your math is correct.
The were allowed to exercise, but not to extreme.
Permalink Reply by DURIANRIDER on I physically couldnt eat 6600 from fruit for days on end unless I was doing live talks or training hard.
I remember years ago being in Thailand and TRYING to get fat on durian by stopping training but my appetite just went down so much. I was just laying on the beach and surf'n the net. Zero stress to burn anything up or create the caloric deficit that drives a solid hunger. I got bored of the inactivity so had to quit the experiment.
Permalink Reply by Reed on Subjects weights returned to their beginning weights two days after the overfeeding period.
I think I caught a few missed points. The 3 control subjects were "carb depleted" for 3 days so that's why they could carb load on average 800-900 grams compared to the 500 or so if they didn't carb deplete before the carb load. But the 3 subjects were not balanced. One added 1146 Grams of carbs while the other two were 629, 654 grams respectively? The carb "depletion" then overload is a known trick many of us do before a long race to overload our carb stores.
Because of the 3 day carb depletion phase and 4-5 days of carb loading. These guys only had about a 3-4 day window when their bodies were fully carbo loaded to where fat would be quickly added. So the 1.1 pounds of fat gain makes since 1 pound of fat has about 3500 calories in it. 14 days of solid carb overloading would have had much different results.
The reason for the weight returning to normal was because they were starved for 48 hours at the end and an aditional 48 more hours of carb depletion. Two days of 110 Grams Protien, 5 Grams of fat and 0 Carbs. That's about 500 calories per day on days 11-12. Then they did 2 more days of carb depletion with a higher fat 42-65 grams of carbs per day diet.
The other odd thing in this study. Out of 14 days, 5 were very low carb (approximate 50 grams per day) 2 days were 0 carbs. 7 days were very high carbs.
Why all the diet changes? Why not just carb load for 14 days?
Low carb Keto Diet <--> then <--> High carb diet <--> then 0 carb diet major keto diet <--> then <--> low carb Keto diet.
Permalink Reply by Ana on The 3 control subjects were "carb depleted" for 3 days so that's why they could carb load on average 800-900 grams compared to the 500 or so if they didn't carb deplete before the carb load. But the 3 subjects were not balanced. One added 1146 Grams of carbs while the other two were 629, 654 grams respectively? The carb "depletion" then overload is a known trick many of us do before a long race to overload our carb stores.
Since the object of the study was to see how much glycogen muscles can store, wouldn't they necessarily have to deplete the glycogen stores, Reed? The researchers admitted they underestimated when the stores would be depleted, which accounted for the varying amounts of glycogen needed to replete the stores. (Like if you wanted to know how big a gas tank is by filling it with gasoline and you didn't get all the original gas out~wouldn't you have to account for the original gas in the tank?)
I don't think there was a "trick" here. How silly. Who are they tricking? They just want to know how much glycogen the muscles can hold.
Permalink Reply by Reed on A trick as in tricking "your body" to allow more Glycogen storage. Not to trick the public. It's just something many long distance athletes do to prevent bonking.
Bodybuilders also do this with salt. They overload salt then restrict to get the ripped look as it flushes out subcutaneous water.
Permalink Reply by Ana on HI Carrie,
I another study I've been reading (I'm not finished with it yet), about brown-tissue fat thermogenesis, I scanned down the page and saw a discussion about insulin resistance and the fact that it did not affect thermogenesis. That is, fat storage remained the same in animal subjects in spite of insulin resistance. Researchers concluded that fat-burning must occur somewhere else in the body than in the brown fat, although it hadn't been discovered where at the time of the research. If you'd like, I will post what I read in that study when I'm finished.
Permalink Reply by Adam on Hey Carrie
Insulin resistance does increase the storage of carbohydrates as adipose tissue. There is one reason and one reason alone that de novo lipogenesis (increased body fat creation) occurs: At some point, there is more sugar in our bloodstream than we can get out of the bloodstream and into our cells to be metabolised into ATP in our mitochondria, in an appropriate amount of time. Storage as body fat as two properties:
Firstly, it is a safety mechanism. High blood sugar levels are dangerous. This about the complications of poorly managed long term diabetes (retinopathy, blindness, kidney disease, cardiovascular disease, ulcerations etc). These are all caused by damage from chonic high blood sugar levels. Glycosylation is a process where sugar binds to proteins in the body and causes irreversible changes (damage) to the proteins, making them not only functionally useless but also potentially can create free radical activity. Conversion of sugars to fats is something we can do quickly and efficiently, which makes it a safe, practical way to preventing damage and death.
Secondly, it is a way conserving energy - we don't like to waste energy, since we never can be too sure when the next famine is on its way. Or when we might need to dip into our reserves of fuel. So rather than just get rid of excess dietary energy, we store it for later use. Waste not, want not.
Insulin resistance is essentially where, for a variety of potential reasons, insulin is unable to initiate the transport of glucose from the bloodstream across the cell membrane. This prevents it from being oxidised. There are lots of reasons for insulin resistance - micronutrient deficiency (energy metabolism is one of the most nutrient demanding jobs), toxic metal exposure (many toxic metals disrupt mitochondrial function and act competitively against nutrients in energy metabolism), chronic stress (cortisol, adrenaline and noradrenaline all reduce insulin sensitivity in order to ensure adequate sugar is available to the brain, in preference to other cells during a survival based stress response, since many neurons or brain cells, are not dependent on insulin to metabolise glucose).
So anything that stops sugar getting out of the bloodstream (like insulin resistance) means that there is nothing else to do with it except store it as fat. That is why diabetes is associated with being overweight.
Take care
Adam x
Permalink Reply by TheBananaGirl on That is why diabetes is associated with being overweight.
- Just looking at the last sentence Adam, I don't think it's entirely accurate. Take a look at what most diabetics eat! Fatty JUNK. They eat a high fat animal-based diet (weight-gainer) then try to address the symptom of that diet (diabetes) by injecting themselves. Maybe I just misunderstood what you are saying.
Permalink Reply by Rune Solli on I think you misunderstood what he meant Freelee :)
In the mainstream, carbs make you fat (its a fact and no way around it lol). And when you have excess glucose in your bloodstream, that obviously gets stored as fat and it makes you fat. Ofc, i might have misunderstood, but the way i interpreted it, Adam said that it is "associated" with being overweight (by the mainstream). Did that help any? :P
Larissa Barrett replied to Gwen1472's discussion Tiredness when starting this lifestyle... in the group 811 UK
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