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
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.
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.
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.
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.
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.
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.
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.
I think you have partially misunderstood what I am saying. High blood sugar levels are always the reason for storing fat in the body. However high fat intakes are correlated with obesity for several reasons, especially in diabetes.
Overweight people, in general, do not just consume a high fat diet. They consume a diet that is high in all of the macronutrients. Invariably, because people consume animal products that are high in saturated fats, they consume not only high fat intakes but also high in protein. If they just consumed a high fat, high protein diet, the chances are they probably wouldn't have high blood sugar levels and therefore probably wouldn't get that fat. Probably the opposite infact. But as we know, low carb, high protein , high fat diets are difficult to stick to for a reason - they are diets that we evolved to consume when times were difficult, not out of preference but out of necessity to survive when there was nothing better to eat. Hence people who are overweight consume not just high protein and fat intakes, but also high carbohydrate intakes. But not carbohydrates per se - they consume foods that produce a high glycaemic response, and a high insulinaemic response.
Eating fat doesn't mean it will be stored as fat - unless there are high blood sugar levels. Since higher protein intakes reduce calorie requirements, and many high protein foods increase the insulinaemic response (insulin is an anabolic hormone) despite producing a low glycaemic response, and many high protein foods also increase cortisol production (which increases blood sugar levels) and since excess protein is broken down to glucose (and if it may not be needed for dietary energy if there is already enough carbohydrates in the diet, it will be converted to adipose tissue), the high protein foods, in the presence of a high carbohydrate sufficient diet may therefore increase blood sugar levels.
Since high GL, high II carbohydrate foods cause short-term hyperglycemic response, this mean that there is already a higher chance of high blood sugar levels when these two are combined together. But when you add fat on top, you have a situation where there may be reduced insulin sensitivity as a result, and high energy dense foods. If you don't have enough carbohydrates in the diet, fat will be oxidised for energy, which prevents it from causing the reduced insulin resistance and the need to store it as fat in the body. But if you have enough already, there is nothing to do with the dietary fat except store it as fat.
Diabetics typically consume the standard western diet. This is not just a high fat, or high protein or high fat diet. It is a high fat and high GL/II carbohydrate and high protein diet. They also usually consume caffeine, which increase blood sugar levels via cortisol, and often consume alcohol too.
It doesn't matter what diet someone is on, if they are gaining weight, their blood sugar levels are too high at some time across a 24 hour cycle, on a regular basis. Or at least they would be, if they weren't converting the sugar to glycogen and body fat. Diabetics have more trouble regulating blood sugar, and are more prone to store as body fat as a safety mechanism as a result.
Neither high carbohydrate, nor high protein, nor high fat diets alone will necessarily lead to weight gain. It is the combined effect that causes problems.
I hope that clarifies what was meant. Let me know if not.
Adam, it seems like you have studied diet and nutrition quite a bit. Is this way of eating the best for weight loss and long term helth, in your opinion?
I guess it depends on what you mean by "this way of eating" and "best" and "weight loss" and "long term". These things will mean different things to different people.
A diet that is plant based, contains a large or predominant portion of food intake from raw foods, and that has a good amount of variety, and is more than nutritionally sufficient (ie. the macro and micronutrients are being met by the specific food choices someone makes), is thought to be supportive of health in many ways. There haven't been any long term studies of fruit based, raw vegan dieters, and there are very few people who have eaten this way long term consistently, to even offer anecdotal evidence. I consider the lfrv diet an experiment, which could be potentially valuable to human health and the planet if successful. Many report feeling good, even better than ever on this diet. I include myself in that category. However there are no long term raw foodists to comment on - this is a new experiment. A handful of people have eaten the diet more than 20 years successfully. People eat all sorts of diets for 20 years. Long term is 70+ years in my opinion. I wouldn't feel confident answering that question in my lifetime until there were thousands of people living til over 100 in perfect health.
In terms of weight loss, again there are so many ways to apply the diet. And it depends what best means. If you mean fastest way to lose weight, then it depends on your calorie intake. Calorie restriction diets are always the most rapid way to lose weight. But not always the most sustainable long term.
I have differences of opinion, slightly, regarding weight loss compared to this forum. I am not of the opinion that one can eat ad infinitum and lose weight. But I do agree that calorie restriction isn't a sustainable weight to lose weight, and think that it is better to have an appropriate amount of calories. The reasons I don't agree with the eating unlimited calories theory promoted by this website is the same reasons outlined in this study.
I do think that a nutritionally sufficient lfrv diet may be one way to lose weight and could be healthy to do so due to the high nutrient density of the diet. Many people do report success with maintaining a healthy weight on the diet. But again, there aren't enough people who have followed the diet "long term" yet to offer a definitive comment. And there has been no research at all comparing the efficacy, either in terms of health or weight loss, on a short or long term basis, with this diet and any other diet.
By not committing to a yes or no answer, that doesn't mean I don't believe it may be beneficial. I just think that anyone who thinks they can know or even strongly believe that this diet is the best for long term health or weight management isn't basing that opinion on evidence. Because there is no evidence yet. From my perspective, that is the point of this forum. It is a place for people who are willing to be human guinea pigs, to voluntarily engage in a dietary experiment for their own curiosity.
I think that you have confused the findings of this study, by confusing the role of glycogen (the storage form of sugar in the body, which is the mammalian tissue equivalent of starch) and of dietary carbohydrates. The study did not report that glycogen converted to fat, nor that glycogen was responsible in any way for de novo lipogenesis. If you re-read the study, you will see that it states that maximal glycogen storage capacity is 15g/kg per which can be increased slightly in athletes. This means that when there is an excess of dietary carbohydrates at any given time across a 24 hour cycle (ie. more carbohydrate calories are consumed from the diet than can be oxidised by the cells for fuel in an appropriate amount of time), the glucose will be stored as glycogen until the stores are saturated (ie. until the maximal storage capacity is reached).
However - and this is the important bit - once there are 500g of glycogen stored in the body, the conversion of excess dietary carbohydrates will not just be as glycogen. De novo lipogenesis (ie. conversion of excess glucose - not glycogen - as well as excess protein and fat, if present, into adipose tissue). This means that even if you keep on increasing your glycogen reserves once they have reached 500g saturatation (which is about 2/3 of the saturation point) your body will not be create more glycogen unless adipose tissue (body fat) increases as well.
Again, this has nothing to do with glycogen converting to fat. It is about glucose converting to fat.
So this idea that we can just infinitely increase calorie intake from carbohydrates whilst on a low fat diet and never gain body fat is a misnomer. Note that the carbohydrate repletion diet in this study was a 3% fat intake and an 11% protein intake, with an 86% carbohydrate intake. This is the 811 diet, but in a cooked food form. And the study clearly demonstrated that when there is a significant excess of calories on low fat, low (but adequate) protein, high carbohydrate diet, it will not all be stored as glycogen, because there is a limit to glycogen storage capacity. Some will begin to be stored as fat, once the glycogen reserves reach 2/3 of their saturation capacity.
Oops. Sorry for confusing my terms, Adam. peace........ana xoxo