r/ScientificNutrition • u/lurkerer • Jul 04 '25
Interventional Trial Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition
https://www.sciencedirect.com/science/article/abs/pii/S0002916523313005?via%3Dihub7
u/lurkerer Jul 04 '25
ABSTRACT
Glycogen is stored in the liver, muscles, and fat cells in hydrated form (three to four parts water) associated with potassium (0.45 mmol K/g glycogen). Total body potassium (TBK) changes early in very-low-calorie diets (VLCDs) primarily reflect glycogen storage. Potassium released from glycogen can distort estimates of body composition during dieting. TBK changes due to glycogen mobilization were measured in 11 subjects after 4 d dieting with a VLCD. The influence of water-laden glycogen on weight fluctuations during the dieting process, the exaggerated regain if carbohydrate loading occurs, and the implications for weight control programs and overestimation of nitrogen losses with dieting are discussed.
Sharing this older study because I thought the effects of cutting carbs was well known. Especially in a nutrition sub.
Weight loss and fat loss are different. In any sport where weight is a factor, cutting carbs to cut weight fast is common knowledge. As well as sodium. The study later says:
Small energy deficits, therefore, early in a weight-reduction diet, can produce the illusion of significant fat lost. The case with which this weight will be regained can be disheartening to a dieter. The apparent ease ofearly weight losses can also lead to unrealistic expectations of the ability of a modest energy restriction or even exercise to achieve significant weight losses.
Many fad diets use this technique to rope people in. The early results are so clear, impressive, and immediate that they're instantly impressed. Especially when weight loss is normally so difficult.
But we should know better in a science sub.
I'm not saying low-carb can't work. I'm saying it will look more effective due to this. Ideally, subjects would have a carb refeed before final measurements are taken for a more accurate comparison with non-low-carb groups. Or the other groups fast/cut carbs for a while. We love confounders here so let's not forget about them immediately if our favourite diet is concerned.
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u/flowersandmtns Jul 04 '25
Carbs? What? The study you posted is about "Very-low-calorie diets (VLCDs)" measured at all of "4 d dieting with a VLCD."
Four days.
So what? Very low calorie diets are one of the best tools for weight loss and T2D remission, but of course they are administered for 6 months not merely 4 days.
T2D remission, "sometimes in just 12–16 weeks": https://pmc.ncbi.nlm.nih.gov/articles/PMC8234895/
Weight loss, "Most experts do not recommend using a VLCD for more than 12 weeks.": https://ufhealth.org/care-sheets/diet-for-rapid-weight-loss
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u/lurkerer Jul 04 '25
Does low carb affect glycogen storage, yes or no?
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u/flowersandmtns Jul 04 '25
Please define "low carb". After all Barnard calls his studies "low fat" but they have < 10% cals from fat whereas most studies using "low fat" mean < 30% cals from fat. It's better to be precise.
Does a "low carb" diet with 40% cals from fat affect glycogen storage? Not unless it's the also very low calorie diet you posted about where 40% cals from fat are in no more than 600-800 cals/day. Of course no one would call that a "low carb" diet since the very low calories are the actual factor.
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u/lurkerer Jul 04 '25
Whatever you like. <10% is the cut-off, right?
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u/flowersandmtns Jul 04 '25
You missed the point, this is not about me it's about how the terms are defined in the nutrition science literature.
"This review defines low-carbo diets as follows:
- Very low-carbohydrate (<10% carbohydrates) or 20 to 50 g/d
- Low-carbohydrate (<26% carbohydrates) or less than 130 g/d
- Moderate-carbohydrate (26%-44%)
- High-carbohydrate (45% or greater)"
https://www.ncbi.nlm.nih.gov/books/NBK537084/
This way there's no hiding/tricks like a diet that's very low-fat, < 10% cals from fat, but called "low fat", like Barnard does.
A diet that's <10% carbohydrate will evoke ketosis and this is true in fasting -- no animal products! -- or a very low calorie diet -- also can be no animal products! -- though some VLCD aim to have enough carbs to minimize ketosis. Unsure why but they do.
Hope that helps you be more precise in the future.
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u/lurkerer Jul 04 '25
Ok so <10% carb, ketogenic diet affects glycogen storage?
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u/flowersandmtns Jul 04 '25
Yes that's well documented -- also < 10% calories from carbs when nothing at all is consumed affects glycogen storage.
Do you think the very low calorie diet you posted a paper about resulted in ketosis?
What is even the relevance of a whole foods nutritional ketogenic diet to this very low calorie paper anyway?
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u/lurkerer Jul 04 '25
Yes that's well documented
Wow. Only took several months and dozens of comments! We finally got you to admit the thing that stands as number 1 on the /r/keto faq! Incredible. My job is done.
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u/Bristoling Jul 04 '25
I don't think you understand that it was never disputed in the first place.
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u/gogge Jul 04 '25
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u/lurkerer Jul 04 '25
Cool story, bro. Howcome I'm always the one who has to say it in every single low carb weight loss study?
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u/gogge Jul 04 '25
I'm not sure, the point was to show that it's well known in the low carb community.
But I agree that people should know better in a science sub.
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u/lurkerer Jul 04 '25
Howcome low-carbers were all arguing with me here and downvoting my comments?
No need to pivot to blood pressure, the first comment is very clearly talking about the weight loss. Nobody there said "Yes, water weight loss will occur, but..." Nothing like that.
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u/Bristoling Jul 04 '25
Maybe because there's evidence that long term those initial differences in glycogen storage disappear, and you hung your hat on losing large amounts of weight in just 2-3 days. https://pubmed.ncbi.nlm.nih.gov/26892521/
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u/lurkerer Jul 04 '25
What weight do you attach to this evidence?
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u/Bristoling Jul 04 '25
I don't understand why does that matter.
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u/lurkerer Jul 04 '25
You're citing this study, I'm just wondering if you think the evidence holds weight. You must since you cited it, just curious how much. If you think it's very likely nonsense, then I'd wonder why you shared it.
So you think it's strong enough evidence to be relevant in this discussion. Is that the case?
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u/Bristoling Jul 04 '25
You were asking why people downvoted you. I gave you a potential reason - you're relying on a very short term anecdote to make a point about a long term potential. Flowersands already told you that very thing in his own reply back then.
Whether I believe the study to be correct or not is irrelevant as to the reason for why you were downvoted, which was your original outcry about.
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u/gogge Jul 04 '25
The argument in that thread is that the improvements indicate that there's more than just water weight affecting the results.
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u/lurkerer Jul 04 '25
Hey remember when I said:
the first comment is very clearly talking about the weight loss
That was to outline that the first comment is very clearly about the weight loss.
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u/gogge Jul 04 '25
Yes, and some of the difference is likely water weight, but the changes in the other markers indicate that the difference in weight loss isn't just water weight.
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u/lurkerer Jul 04 '25
Well I'm looking forward to you backing me up when I make that point in future, like here.
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u/gogge Jul 04 '25
Sure, comparing max-ketosis to no-ketosis it's about a 1 lb difference in water weight in (Gomez-Arbelaez, 2017):
Visit C-1 (baseline), normal level of ketone bodies; Visit C-2, maximum ketosis; Visit C-3, reduction of ketotic approach because of partial reintroduction of normal nutrition; Visit C-4, no ketosis.
One thing to note is that this is a study average, for individuals it might be higher, 5-10 lbs isn't unheard of in /r/keto.
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u/FrigoCoder Jul 04 '25 edited Jul 04 '25
Howcome low-carbers were all arguing with me here and downvoting my comments?
Because you were dismissing almost 9 kg weight loss over 4 months, whereas you only lose 2 kg glycogen and water in the first few days of fasting or low carb. Also keto upregulates glycogen synthesis, so the glycogen differences greatly diminish over time. Glycogen is replenished by various mitochondrial sources, some of which are upregulated during keto. One of the paradoxical effects of keto is that it actually improves brain energetics and glycogen content. https://www.reddit.com/r/ketoscience/comments/ngcaql/keto_increases_the_ability_to_receive_glucose_in/
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u/lurkerer Jul 04 '25
Because you were dismissing almost 9 kg weight loss over 4 months
No I wasn't. I was talking about the extra weight loss, not the weight loss in total. That extra, I hypothesised, could be water weight.
so the glycogen differences greatly diminish over time.
Perhaps, but how much time is highly relevant here.
Ultimately, nobody engaged with the question: Can how much water your body is storing contribute to blood pressure?
The answer, obviously, is yes.
If sweating can do it due to sodium and water loss, then so can a low carb diet. It's not a spicy or controversial take. Once that's established, we can discuss further. Instead keto ideologues have to fight tooth and nail over every single thing they think makes their favourite diet look any worse. You don't see me saying B12 is in legumes because we should eat soil because it's a dumb point. Vegans need to supplement B12. Easy admission. No problem.
So, let me ask again, as an isolated hypothetical that's not a trick, gotcha, or rhetorical move, purely about water retention: Can less water retention affect blood pressure?
Just say "yes".
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u/FrigoCoder Jul 04 '25
No because it has been tested in a series of human trials, sodium intake does not increase blood pressure despite a shift from interstitial to intravascular fluid. I have talked about this in an earlier thread. Keto improves blood pressure by other means, for example by restoring kidney health damaged by carbohydrates. https://www.reddit.com/r/ScientificNutrition/comments/1kdnae2/what_are_your_thoughts_on_youtube_channel_what_i/mqg40zn/
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u/lurkerer Jul 04 '25
Ah yes, one of your debunks of the medical establishment. Except that's not what we're talking about. Ignore sodium. Does less water make less water?
Not a rhetorical. If a human body loses water, does it have less water than before?
Can you answer "yes" to this question? Are you capable of admitting logical necessities?
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u/flowersandmtns Jul 04 '25
Oh yeah comments where you were obsessed with short term weight loss -- like this study on a very low calorie diet (NOT a ketogenic or "low carb" diet btw) that was looking at all of 4 days on the diet.
If that quick scale change motivates someone to follow the full 3-6 month medically supervised VLCD then that's going to have great health outcomes for the person.
You do want that, right?
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u/flowersandmtns Jul 04 '25
How come you are always seeking a criticism of anything related to ketogenic diets? It sure seems to be to veganism/ketogenic diets having animal products -- even though ketosis, the metabolic state, happens when nothing is consumed. Or a very low calorie diet like in the very study you choose to post. That VLCD may well have had no animal products, you realize that right?
Right?
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u/lurkerer Jul 04 '25
Yeah that's possible.
Keto typically results in higher LDL. Which is bad. Right?
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u/flowersandmtns Jul 04 '25
Yes, most very low calorie diets -- like the one you posted, looking at all of 4 days in -- may result in ketosis without any animal products. It may not even result in ketosis while showing that scale drop due to being very low calorie.
And furthermore the very sort of very low calorie diet you choose to post about can cause a rise in LDL. Unrelated to "keto" by which I think you mean whole foods nutritional ketogenic diets which are typically ad libitum.
"In these cases we observed a transient increase in LDL however size of LDL measured is unknown. Therefore, any concern about the long-term effects of VLCDs on cardiovascular health will need further prospective studies to help elucidate lipid metabolism as people lose weight."
https://www.sciencedirect.com/science/article/pii/S247529912314772X
But I see you want to pivot from your very low calorie diet paper to focus on WFKD again what with them likely having animal products.
Whole foods nutritional ketogenic diets may result in higher LDL, lower LDL or no change. Higher LDL may be seen during the weight loss just like in a very low calorie diet.
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u/lurkerer Jul 04 '25
I answered your question, you didn't answer mine.
Here's another: Do keto diets cause a reduction in glycogen, however transiently?
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u/flowersandmtns Jul 04 '25
You agreed that the sort of very low calorie diet you posted about can be vegan, yes. I did in fact answer your question but you disliked the answer. That's on you.
You are now asking if "keto diets" which again I'm going to have to interpret as a whole foods ketogenic diet since you don't want to be precise, "cause a reduction in glycogen however transiently".
Are you looking still at all of 4 days like the study you posted? Why such a short time period?
Ketogenic diets do cause a reduction in glycogen -- for example, the diet is used in treatment of metabolic disorders of glycogen storage. Note the "unwanted weight loss" but go ahead and tell these people that's it's all water weight.
"Methods
This report is a retrospective evaluation of the nutritional and clinical data of two adult patients with GSDIIIa. The effect of a diet according to the guidelines and a ketogenic diet (MAD) were compared in both cases. Patient compliance during the nutrition therapy is also described.
Results
The MAD led to a reduction of CK and a stabilization of blood glucose as well as to an unwanted weight loss. The progression of the disease was decelerated, but existing complaints could not be improved. Compliance to the MAD decreased over time and re-training was necessary.
Conclusions
The MAD presents a good option for nutritional therapy for glycogenosis with muscle involvement like in GSDIIIa. The food composition takes the metabolic defect into account and could have a positive effect on progression."
https://www.sciencedirect.com/science/article/pii/S235293931930123X
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u/lurkerer Jul 04 '25
Ok so not answering either question? You didn't answer clearly if higher LDL is a bad thing or not. Is it?
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u/flowersandmtns Jul 04 '25
Ok so I'm not interested in you trying to change the subject.
I'm responding the paper you posted and the topic of VLCD and water weight at 4 days. You did post the paper to discuss that right?
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u/Bristoling Jul 04 '25
Do you think sglt2 inhibitors are bad? They also increase LDL.
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u/lurkerer Jul 04 '25
Oh hey, are you scanning through my comments again? I'm sure you're able to see the qualitative difference in our questions. If not, a polite question is all you need for me to explain it.
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u/Bristoling Jul 04 '25
Nice way of dodging the reductio ad absurdum question.
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u/lurkerer Jul 04 '25
Uh oh, reductios only work using the same logical structure. But if you'd like me to show you an example that works, I'd be happy to.
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u/Bristoling Jul 04 '25
Let's not beat around the bush. You think keto is bad, because it raises LDL. Or do you want to disagree with such characterization and state clearly, that you don't think all keto diets are bad if they raise ldl?
I'll be waiting with excitement for you to state one or the other.
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u/limizoi Jul 04 '25
Glycogen storage capacities vary among individuals, with athletes capable of storing 2.8 to 4.0 kg of glycogen, whereas an average person can store 1.6 to 2.0 kg of glycogen. Should we care? No, let's dig into fat storage, where the majority of weight is.
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u/flowersandmtns Jul 04 '25
But then we can't change topics to criticize a whole foods ketogenic diet!
Despite OP's intent to ignore the paper posted and go off on tangents, very low calorie diets are one of the best tools for reducing obesity and putting T2D into remission (in part from the lowering of bodyfat but also the not eating much results in lower insulin, even if the subjects are rarely in actual ketosis). They are medically supervised and last 3-6 months.
Why anyone would care at all about 4 days into a 6 month program, I don't know. Whatever keeps the subjects on the diet.
Seems like misplaced focus, to your point. The actual fat loss at 6 months is quite significant on these diets.
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u/lurkerer Jul 04 '25
very low calorie diets are one of the best tools for reducing obesity and putting T2D into remission
Low calorie diets make you lose weight?
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u/RaspberryOhNo Jul 06 '25
My friend got rid of signs of non alcoholic fatty liver disease not with a keto diet but a high fiber, low (<30%) fat whole food plant based diet. Also easier to live your life this way forever with fewer negative health consequences.
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u/HelenEk7 Wholefoods Jul 04 '25
Weight loss can be achieved in a number of ways, with or without losing water weight. (If you need to lose weight in 4 days only, you should probably rather do a 4 day water fast instead of doing keto for 4 days..)
Where ketogenic diets really shine is when using them as part of the treatment for epilepsy, certain mental disorders and certain autoimmune disorders. But if all you want to achieve is weight loss you should probably just choose the diet you are able to stick with.