Reading this article I'm a little confused by the author's conflation of brain energy and the energy expenditure of the body as a whole. In the beginning they mention:
> "Your brain consumes roughly 20 to 25% of your body's total energy at rest"
while later they say:
> "Even chess grandmasters, who sit for hours in states of intense concentration, burn only about 1.67 calories per minute while playing, compared to 1.53 calories per minute at rest"
That second figure seems to refer to whole-body expenditure, not just the brain. And intense cognitive work doesn't happen in a metabolic vacuum - there's increased cerebral blood flow, elevated sympathetic nervous system activity, changes in heart rate variability, hormonal shifts (cortisol, adrenaline). These all have systemic metabolic costs that go beyond the glucose the neurons themselves consume. So the "it's just a banana and a half" framing might be undercounting by quietly switching between brain-only and whole-body measurements.
Also somewhat related - the link to businessinsider about chess grandmasters is broken, but another very interesting rabbit hole here is how energy expenditure is actually measured. A lot of what consumer devices and even many studies report is based on proxy biomarkers like heart rate, HRV, weight, age, and sex, run through linear regression models. True calorimetry (indirect via gas exchange, or direct in a metabolic chamber) is expensive and impractical outside lab settings. That means the precise calorie figures cited with such confidence - the "100 to 200 extra calories" from a day of thinking, or the per-minute burn rates of chess grandmasters - likely carry wider error bars than the article suggests. We don't really have a great way to measure real-world energy expenditure accurately at the individual level, which makes me a bit cautious about the neat narrative of "thinking is calorically cheap, full stop."
That said, the core point about adenosine accumulation and perceived exertion affecting training quality is fascinating and well-supported — that part of the article is genuinely useful regardless of the calorie accounting.
Can you expand on that please? Because I can tell you as a matter of fact that when I go for a run for an hour I burn well over 800 calories.
Sure - how did you arrive at the 800 kcal figure? Most likely a wearable or an app, and those estimates are based on rough linear regressions from weight, age, sex, and heart rate - not actual calorimetry. The error margins on those numbers are significant, but the devices present them with false precision that makes people treat them as ground truth.
Even setting accuracy aside, the framing is the issue. Your basal metabolic rate - just keeping your organs running, blood circulating, cells maintained - accounts for 60-70% of your total daily energy expenditure. Add the thermic effect of food (~10%) and you're at roughly 70-80% of your energy budget spent before you even lace up your shoes [1]. Exercise typically makes up the remaining 20-30%. So that hour of running, while genuinely beneficial for a hundred other reasons, is a relatively small slice of your total daily burn. And not all calories are equal on the intake side either - your body spends 20-30% of the energy in protein just to digest it, compared to 0-5% for fat, so "800 kcal burned = 800 kcal of anything eaten" doesn't hold up.
That's what I mean by "myth" - not that exercise burns zero calories, but that the popular mental model of "I ran for an hour so I earned X calories of food" is built on inaccurate measurements, treats all calories as interchangeable, and overweights exercise relative to what your body spends just existing. Curious though - do you track your intake with the same rigour, and if so, do you find the numbers actually add up in practice?
[1]: https://my.clevelandclinic.org/health/body/basal-metabolic-r...
I don't have the background to fully evaluate how true that is. I read "Burn" by Herman Pontzer, which at least makes a very good case for it.
So if you view this from a time use perspective, just skipping that sandwich is way better than running for an hour. And many people can't spare an hour a day just to make up for a sandwich. Hence - "not a lot" - Its too expensive time-wise for the caloric balance effect it provides. Just skip the sandwich instead.
Depends on your level of exercise. I often cycle 100km per day and can tell you if I ate only the 2000 kcal I hypothetically need I would go into a strong deficit.
Right, and that's kind of my point - the "2000 kcal" figure is itself part of the problem. It's a rough global average that doesn't account for your sex, age, weight, body composition, activity level, or even climate. It's a number on a food label, not a physiological reality for any specific person.
And even if you could nail down your actual total daily energy expenditure, calorie counting treats all calories as equal, which they aren't. Your body spends 20-30% of the energy in protein just to digest and metabolize it, compared to 5-10% for carbohydrates and 0-5% for fat. So 100 kcal of chicken breast and 100 kcal of butter are not metabolically equivalent - your body nets significantly less usable energy from the protein. This is the thermic effect of food, and it alone accounts for roughly 10% of your total daily energy expenditure.
Speaking of which - basal metabolic rate (just keeping your organs running, blood circulating, cells maintained) accounts for about 60-70% of total daily energy expenditure. Add the thermic effect of food on top and you're at roughly 70-80% of your energy budget spent before you even stand up from bed [1]. Physical activity - including your 100km rides - typically makes up the remaining 20-30%, though obviously that range is wide and shifts dramatically for endurance athletes.
So yes, of course people who cycle 100km need more fuel. Nobody is disputing that. My point is that most people vastly overestimate how many calories exercise burns relative to what their body spends just existing, and they use kcal as a universal unit of nutritional value when the body's actual energy extraction varies significantly by macronutrient composition. People optimizing purely on calorie numbers are working with a model that's far rougher than they think.
And this whole picture gets worse with wearables pushing calorie counts front and center. You see it all the time - "my wearable shows that i burned 300 kcal with that activity so it zero outs that sweet thing I ate earlier that was also 300 kcal" That's wrong on multiple levels - the device estimate is inaccurate to begin with, the thermic processing of that pastry isn't equivalent to the "300 kcal" on its label, and your body doesn't do neat arithmetic like that anyway. But with every fitness app and smartwatch plastering a big kcal number on your workout summary, it's becoming the default way people think about food and exercise, and it's reinforcing exactly the wrong mental model.
[1]: https://my.clevelandclinic.org/health/body/basal-metabolic-r...
Many people tell me I need to lift weights to lose weight.
On mornings when I actually put in real effort, I pay for it with a significant cognitive performance penalty for the remainder of the day. I want to do nothing more than sleep an hour after a workout, which is bad timing, because that's when I need to clock into work.
I stay hydrated, get enough sleep, etc. People tell me that I'm over training, which is ridiculous, because anything less would be easy and contravene the purpose of the workout.
This is why I prefer to exercise in the evening, but there are known negative effects [0] of physical exertion on sleep quality.
If I actually did all the exercise I needed to do at the gym in the morning, then I'd probably have to sleep at 9:00 PM and wake up at 4:00 AM. There's no room to live in that schedule.
Even once is rare unless I've been out drinking for the night.
I can see why every vegetarian should take it. But if you eat meat regularly, your creatine stores will be at a level where you'd probably only see a cognitive benefit at times of sleep deprivation. But if you're regularly sleep-deprived, then you'd do best by addressing your sleep issues.
The big copy on the front page says:
> Your Apple Watch *tracks* VO2 Max—one...
While you have to read through FAQ where you see:
> The watch *estimates* your cardio fitness during outdoor activities and stores it in Apple Health, which our app reads automatically.
All emphasis are mine.
I think it's a little disingenuous to sell this as "Your VO2 Max, finally visible" when it's actually just an estimate from a watch, based on biomarkers. When the real VO2 is measured in a lab with a more involved equipment.
A 2025 validation study involving 30 participants found that Apple Watch underestimated VO2 max by a mean of 6.07 mL/kg/min (95% CI 3.77–8.38) when compared to indirect calorimetry, the gold standard method. The mean absolute percentage error (MAPE) was 13.31%, and the limits of agreement showed considerable variability ranging from -6.11 to 18.26 mL/kg/min [1]. Another 2024 study found similar results, with the Apple Watch Series 7 showing a MAPE of 15.79% and poor reliability (ICC = 0.47) [2].
[1]: https://journals.plos.org/plosone/article?id=10.1371%2Fjourn...
You don't suffer from a lack of time, but rather a lack of energy. And actually, you don't suffer from a lack of energy, but a lack of activation energy.
We colloquially refer to activation energy as motivation. But maybe that's not the whole story. Some of it is willpower and personality, but maybe some of it is a buildup of adenosine.
This squares with my personal experience. It's harder to start things after day's worth of intense mental effort.
https://www.science.org/content/article/mentally-exhausted-s...
Willpower is limited. Hard workout means intense cognitive effort is much harder to pull off.
It takes at least a week until it gets stored in the brain if you start taking it.
For me as N=1, training after thinking is easier than the reverse.
Found myself practically stop longing for sweets during programming; have more energy during workouts (135 KG bench press and all the other stuff).
5 g daily is what considered to saturate your muscles.
Some report that any additional helps cognitive tasks (but I haven’t seen definitive studies besides the sleep deprivation).
I take 7.5 g
They list a study and more info on that page. Probably why almost all pre-workouts include caffeine. Some push for 300mg per serving.
Yohimbe gives some weird heart effects also.
Training light is a great way of winding up doing a whole lot of nothing.
Give time to ramp-up. I like to start 2-3 days with things like the "7 minute workout" before dive in into anything more complicated.
Is better quantity than "quality" until you actually can put the discipline and consistency. If not, just walk is good enough
If you're exercising to lose weight, you're probably thinking that more exercise means more weight loss, which means that you could be overtraining.
I recently got a second Apple Watch to wear to bed to track my sleep, and it's given me some really great insights into when I'm hitting the red zone and need to dial back training. For exercise, more intensity is not always better. What matters is consistency, not consistently high intensity.
No you dont. Exercise does help, and has many other benefits but is not the main driving factor for losing weight. Diet is by far the most important one. Calories intake vs expenditure is the only thing you need to worry about if your primary goal is weight loss.
This doesn't mean you aren't over training.
If it's strength training... Without knowing the specifics what you are describing sounds like too much volume (and training for hypertrophy). Lower reps (3-5) & higher weight will have more of a strength stimulus and be less taxing.
If it's cardio... you probably should be at a lower intensity and going for longer.
Exercise a little earlier in the evening?
This is stupid. All you need to do is to get used to being hungry to the point of losing 0.1kg/day and measure yourself a lot (I'm doing the same).
Actually for me working out increases my appetite, and I feel like I have to eat so thar the gym session doesn't go wasted.
The website owner didn't even bother to check for hallucinated links, though https://journals.physiology.org/doi/full/10.1152/japplphysio... does exist and somewhat backs up the clickbait headline, so it would be satisfying comeuppance if the mods could just replace the submission accordingly.
Granted, you don't like to like this style of writing, I don't either. But you don't have to auto-accuse AI writing either. Also, there's nothing wrong with using AI to rephrase a manually written text for better readability, plenty of people use AI for that too rather than writing the entire thing.
I'm worrying that soon, I will have to hunt for non-AI essays by them just being worse written/more 'crude' and not as eloquently written as an AI would do :-/ Basically, seeking out "authentic human slop".
For the record, an AI detector that appears to have put work into reliability and that I trust very much from my own testing, Pangram (https://www.pangram.com), says this is 100% AI generated. I've used it plenty before when experimenting with AI-collab writing, both fiction and non-fiction, and it's frustratingly accurate in identifying what is and isn't my contribution. I have since largely given up trying to do AI-collab writing, because no matter how nice the writing looks in the moment, it always reeks when read closely, or on later days.
(Also have a look at Wikipedia how to identify signs of ai writing.)
> Here's the part that surprised me:
Might as well have said "here's the kicker" and used emojis instead of bullets. Maybe you can share your reading sites as you seem rather undrrexposed to not recognize this immediately lol.
Edit: I mean come on man, how can you not tell?! I'm still cringing from this one:
> The incremental cost of actually thinking hard? Almost nothing.
Edit II
"This isn't one study"
Dum dum dum. Sooo dramatic. 100% slop.
I asked "Can you give me a short essay on the history of fire." Maybe the type of writing requested has a massive effect on the language used?
"Here is one paragraph of an idea, an abstract of a report. Write a blog post."
Whereas a "history of fire" contains no article in the prompt and so might have more material from its own auto complete database to draw from.
Most of the computation and learning that occurs is attributable to the relative timing of spiking events. A lot of information can be encoded in the delay between 2 spikes. The advantage of biology is that there is no explicit quantization of the time domain that must occur. Biology gets to do a lot of things "for free". Simulating causality in a computer in a similar way requires a priority queue and runs like ass by comparison.
We end up using 100W (2000kcal/day) for the whole body, or about 20W for the nervous system alone (though a nervous system alone wouldn't be able to survive). That's comparable to what a modern laptop uses. Sure, that laptop can't run a large LLM at any reasonable speed, but it can do basic math far better than my brain. By a comically large margin. Just a consequence of the very different architectures chosen
"Artificial neuron" was a useful metaphor at the beginning, but they really are a very simplified model based on what some people understood of neurology back then. They are not that useful to get insights into how actual neurons work.
I know the metaphor isn't exact, it's just how i thought of it.
That specific aspect might end up irrelevant for dieting, which is exciting since it flies in the face of intuition. It seems that when it comes to long-term modes of existence (as opposed to, say, the one day of the marathon) the "activity level" doesn't really affect how much energy your body uses.
> In this study, we used the doubly-labeled water method to measure total daily energy expenditure (kCal/day) in Hadza hunter-gatherers to test whether foragers expend more energy each day than their Western counterparts. As expected, physical activity level, PAL, was greater among Hadza foragers than among Westerners. Nonetheless, average daily energy expenditure of traditional Hadza foragers was no different than that of Westerners after controlling for body size.
https://journals.plos.org/plosone/article?id=10.1371/journal...
You’re not having someone else take it for you?
> I experienced this pattern without understanding it. My Tuesday evening interval sessions, scheduled after long workdays, consistently felt worse than my Saturday morning sessions. I blamed sleep, stress, hydration. Those all matter, but the research suggests the cognitive load itself was a primary culprit.
Over the last few of decades there's been a lot of lab research calculating the gross efficiency of the human body with different factors (size, sex, fitness etc) and I think these estimates that sports apps give are very close.
If you cycle with with something that can measure power output you can calculate the mechanical work done by the body exactly during that exercise period and convert to energy "burnt" (1 watt/hour = 3.6 kJ = ~0.86 kcal). 220 Watts for an hour (I couldn't do that but a good cyclist can) is about 800 calories.
Not that doing x work doesn’t burn y energy, but that +x work in exercise does not burn +y energy at the end of the day.
Exercise is an alternate heat source, approximately 1-to-1 with thermogenic heat (albeit, not distributed as evenly). So much so that our body has to switch to cooling strategies.
And the body can respond to exercise expenditures by reducing other expenditures and using calories more parsimoniously in other dimensions.
It is interesting that during periods in which I have a habit of daily low intensity exercise, I feel like I have more energy than periods I don’t do any exercise, even if my calorie intake is the same.
Another noticeable effect is any allergies from local plant life I get clear up quickly during and after exercise. My immune system runs a tighter, less reactive ship.
Those baseline calories are not just often underestimated in a static sense, but are also dynamically adaptable.
One reason may be is that we evolved to burn far more overt calories through a day than our extra-exercise day burns. Our body has mechanisms for storing surpluses but almost certainly raises baseline use as well. Which is easily diverted back to exercise.
On the other hand, beyond any net expenditure from regular lifting weights (as work), to the degree greater muscle mass is achieved and maintained, weight lifting directly raises the body’s baseline expenditures.
In the same vein as much of the rest of what you're saying, the other thing that I feel like people always neglect with their "Calories in/calories out" and "Bodies can't violate thermodynamics" is that the human body can adjust how efficiently it processes food, colloquially known as a "slow" or "fast" metabolism.
While it's true that the human body has no answer to a true calorie deficit (except the incredibly powerful and effective one of tweaking satiety and hunger signals), as long as you're eating more calories than you're strictly burning, your body can simply take longer or less time to digest the food you put into it and extract more or less energy from what you're eating, which can make an enormous difference without you changing your intake at all. Which means that people can absolutely eat identically, have identical appetite levels, and have extremely different body types.
If you're exercising more, sure, your body will make you more hungry, but it will also work harder to squeeze every possible calorie out of what you're already eating. If you cut down on what you eat, your body will work even harder at it, to the point that you could literally eat less, work out more, feel hungry and tired all the time, while getting fatter, because your body is worried that you're in a famine and in a physically stressful environment and is desperately trying to signal to you to conserve as much energy as possible, eat as much as possible when you find food, and at the same time trying its best to make the most of the food you give it.
And at the same time, someone else's body might simply not do that. It's crazy!
I don't track consistently anymore only when I'm working towards a goal but when I have more than 2 weeks data these days it seems pretty spot on to the point I can calculate the tracked captors to target to get the desired rate of change in weight pretty consistently.
I agree with all you posted.
> Curious though - do you track your intake with the same rigour, and if so, do you find the numbers actually add up in practice?
To return the courtesy, for the purposes of discussion I picked a rough estimate and rounded down significantly the actual amount I typically run. More often it's 1.5 hours a run and supposedly >1000 calories given my weight, heart rate, terrain, and speed. I also assumed the calculations are way overestimating my actual calories spent so just went for something somewhat plausible for the sake of a HN comment. As you noted calories aren't accurately reported by devices. I do not pay attention to it in massive detail either. But in practice since I run an average of about 25km a week but can vary from 0 for some weeks to 50 for others and I keep relatively good eye on my diet I notice significant changes in weight over time that tallies with effort. Three months of below that 20ishk a week and I will put on 2-3kg. The next three months I increase to 35ish+ a week and it drops off again. Would I swear to it in a court of law that I'm not miscounting meals? No way. But I feel reasonably comfortable that this is an accurate description.
The brain does increase energy expenditure with activity, but as said in the article, it's quite minimal.
I have been tracking caloric input very precisely and energy expenditure with an Apple Watch (one of the most precise trackers) for a while, and I can guarantee you it all adds up.
In fact, once everything is calibrated, I could predict my weight loss/gain with a 5-10% margin of error at worst (mostly due to imprecision in food calorie accounting and inaccurate energy expenditure tracking).
Too many people try to mystify something that is extremely simple. There are some things to care about (like not going too low on the protein), but it really is all about getting the same amount of energy that you are spending, and that's pretty much all there is to it.
I seems like it's only part of the story. If you increase exercise but also increase calorific input to match then you won't lose weight. But, the laws of energy conservation being what they are, I don't think anyone disputes that if you very significantly increase exercise but also maintain calorific input then you will lose weight as the energy must come from somewhere and there are only so many optimisations your body can make. You could of course maintain exercise levels and reduce calorific input for a similar effect, ignoring health benefits of exercise. Take an extreme case, Michael Phelps. He used to eat 12,000 cal a day because of the hours he spent swimming. Certainly not a small guy but pretty lean! So I'm totally prepared to accept there are bounds to all these statements but I still think I couldn't finish an 800 cal sandwich for lunch hehehe.
By the way, I feel the Wikipedia page there uses a lot of words suggesting that the paradox isn't at all fully understood and that there could be compensating mechanisms we aren't aware of. But I'm not in a position to dig deeper.
This is exactly what is disputed by the link you posted. They measured directly the energy expenditure (the number of calories burned by respiration) in a high-activity hunter-gatherer tribe, and in relatively low-activity industrialized societies, and found they were almost the same. So the number of calories the people consumed was not measured or relevant (and must also have been roughly the same if neither group was actively gaining weight).
But whether that means that your body will have a calorie deficit of that same amount, that is much harder to prove.
For me the line "The studies suggest that controlling caloric intake may be more necessary for managing weight than exercise alone." is a possible conclusion for the apparent paradox. Note the words "may" and "alone" which indicate uncertainty. I deliberately used the phrase "very significantly" to suggest we would probably all agree that there is some bound on observing the paradox which is why I used Phelps as an example. To repeat and be clear, I think the paradox as described on the page does not say that with a very significant increase in energy expenditure there will be no weight loss with a constant calorific intake.
And also that the calorimetry from wearables is highly flawed and it seems to that we don't have super accurate data and what sort of activities burn the most energy.
I am also a big opponent of folks that start equating the "my wearable shows that i burned 300 kcal with that activity so it zero outs that sweet thing I ate earlier that was also 300 kcal" which is wrong on so many reasons but with a lot of workout apps and devices pushing the (inaccurate) kcal count front and center becomes more and more a of a thing.
Maybe AI is being trained on my writings.
Edit: Maybe because I was raised in the 80s, but this style of "asking a question to introduce a topic" was very common back then.
Wait you can tell from this that it's written by a LLM? I think you're written by a LLM...
Great point.
> If you're exercising more, sure, your body will make you more hungry, but it will also work harder to squeeze every possible calorie
I find when I only do light exercise, that I am less hungry than when I don't exercise. Perhaps because I get better sleep, I am less hungry.
All the dynamics are crazy.
There have been so many of these threads where someone says "CICO!"
But, biology is complex! So, thank you for summarizing a few of the many complexities here!
> The authors hypothesized that it could be that the body reduces caloric spend on other things, like stress responses
I just take 5g/day with my morning coffee/water.
Rhonda Patrick has made several YouTube videos about creatine and you can find more information about creatine at her website - https://www.foundmyfitness.com/topics/creatine.
One of her creatine videos mentions that your muscles will take up ingested creatine faster than the brain. So for any creatine to make its way to the brain, your muscular creatine stores must be topped up first.
I think dosage would depend on the amount of daily physical activity. If you work out a lot, you'd have to replenish your muscular creatine stores before the brain could access any/much.
She also mentions boosting creatine dosage after bouts of mental exertion.
And an earlier 2018 article [2] argued that "Evidence suggests that the blood–brain barrier is an obstacle for circulating cre- atine, which may require larger doses and/or longer protocols to increase brain creatine as compared to muscle. In fact, the broad spectrum of creatine sup plementation studies that span different dosing pr- tocols (e.g. high-dose short-term, low dose longer- term), co-ingestion of other nutrients/compounds (e.g. carbohydrate, protein, insulin), different popu lations (e.g. vegetarians, elderly, patients, athletes) is unavailable for brain creatine adaptations"
1: https://www.nature.com/articles/s41598-024-54249-9
2: https://www.researchgate.net/profile/Bruno-Gualano/publicati...
This is probably an important difference from the average participant of those studies.
The "Energy paradox" is not a logical paradox at all. It is just a confusing fact. The observed fact was that two different groups with apparently very different activity levels respire almost exactly the same amount. In other words, that an increased, but not necessarily extreme, level of mechanical work does not appear to correlate with an increased level of calorie burn. Not just that the relationship is non-linear, that the relationship does not seem to exist at all (at the measured level of exercise).
I was very careful with my words this time, hopefully there is no more misunderstanding. I think we still disagree unless by "very significantly increase exercise" you mean something like running multiple hours per day every day.
Even Tesco's bacon & egg triple is only 550 : https://www.tesco.com/groceries/en-GB/products/260422235
I'm struggling to find anything I'd describe as a sandwich come close to 800 calories.
EDIT: the trend holds pretty well at the footlong size (which is a big sandwich). 18/26 sandwiches they offer are >1000 calories.
Secondly, I can't see how you can get to 1320 calories for a footlong italian going by this: https://www.subway.com/en-gb/-/media/emea/europe/uk/nutritio...
Even counting footlong bread + footlong Italian Sub it only comes to ~1100.
And as it makes clear, a footlong is 2 6" servings, it's disingenuous to pretend that's a sandwich.
https://en.wikipedia.org/wiki/Peanut_butter,_banana_and_baco...
Big Mac = 580 Cal.
I'm going to eat lunch one way or another and for me it's going to be under 800. Skipping meals isn't really a good choice, imo, but ok.
If you want to lose weight, it's far easier to remove 800 Cal from your diet, at least time wise, then it is to exercise 800 Cal's worth every day.
Either way, if you're losing weight at any appreciable rate, you will feel hungry (at least if it's not chemically induced in some way, such as chemo or GLP-1 inhibitors or similar). That's just something you have to get used to if you want to lose weight.
The calories in/out model isn't wrong exactly, but it's so reductionist that it becomes misleading in practice. It omits hormonal responses (insulin, leptin, ghrelin), the thermic effect differences between macronutrients (your body burns 20-30% of protein calories just processing them vs 0-5% for fat), gut microbiome composition, sleep quality, stress hormones, meal timing, and individual metabolic variation. Two people eating identical calorie counts can have very different outcomes. Telling someone "just eat less and accept the hunger" without any of that context can set them up for a miserable yo-yo cycle - or worse, a disordered relationship with food.
That I absolutely agree with and so do my legs ;)
I only found the suggestion that exercise _doesn't_ burn calories a bit weird.
> you will feel hungry
That I also agree with... all this talk of sandwiches!
Sure it's easier to fast but you're missing out on the other benefits associated with exercise.
As for nitpicking on calories: the Subway site is incredibly tough to navigate. Just use https://subwaymenupedia.com/, since averaging across location is really tough.
I wish my point were uncontroversial: millions of people buy footlongs that are over 1000 calories as a regular habit. I'm critiquing folks that are incredulous about this. Subway is just an example, you can also look at Quizno's (back in the day) and Jersey Mike's (the modern equivalent). Even my local deli serves sandwiches well beyond 800 calories as their special. It's not an interesting argument to have, though. Shops wouldn't offer these meals if folks weren't buying, and I don't believe everyone's doing take-out with the second half for dinner or lunch the next day.
EDIT: Another good source to browse: https://fastfoodnutrition.org/subway
You're really arguing about whether that 800 calorie run could be offset completely by a normal meal. I think it's fair to say that runners doing 800 calorie runs aren't going to Panda Express, but also at the same time:
https://fastfoodnutrition.org/panda-express
Fried rice: 520
Orange Chicken: 370
Total: 890
And most Panda Express orders include two sides, so add an extra ~300 for that (1190).
I think it's fair to say that it's pretty easy for the average American to go out and buy lunch and exceed 800 calories.
I mean... No one said that? The very first comment was about how it's not a lot / not as much as people think, not that it's none.
We have been telling people for decades now to be worried that they might harm themselves by too much restriction and it is just wrong. What is harmful is being over weight. What is harmful is then confusing people that they are somehow going to lose weight without much restriction or being hungry.
This also scales really bad with age because as you age the CNS recovery gets worse and worse compared to muscle recovery.
At 55, there is simply no way for me to lose weight other than being hungry. It is impossible to recover from the amount of exercise that would be needed. The reality is that no one needs to worry about too much restriction until they are down to around 12% or so body fat. The fact a person's bodyfat % is never mentioned in this is exemplary of how bad the standard advise is.
Most people have too much leptin and leptin resistance. Then those same people get the same bad advise over and over to not restrict too much because you don't want to be like an anorexic or extreme athlete and have too low of leptin. Of course, ignoring that the anorexic and extreme athlete are going to have incredibly low bodyfat percentages.
For example, I don't feel satisfied with my meal if I don't feel slightly full. So, what has worked for me is to generally have a single large meal per day, in which I will typically eat whatever I've been really craving since my last meal. In some days that might be steak and brocolli, in other days it might be a McDonald's meal, or some cake. When I get cravings, it's far easier for me to defer them to tomorrow's meal than it would be to just stop eating junk food entirely, or to eat half a burger and two fries from the bag. The exact opposite might be true for other people, and you won't really know until you've tried for yourself.
One thing I will note - I think one of the concerns of the poster you are replying to with focusing too much on enduring hunger is that it might lead some people to develop anorexia, which is indeed a huge problem, even when the person is really overweight (since their anorexia will not just go away once they've lost that extra weight, it will keep going until they get dangerously malnourished).
My point was instead that whatever effort you can spend on weight loss is better spent on managing your diet than increasing your level of activity (though I should also say that fitness is important beyond weight loss). Even when I said you can reduce 800 Cal of food, that doesn't mean "just skip a meal" (though that is also a valid strategy for some people). It can also mean "eat different kinds of food".
However, I do strongly believe that for any weight loss at a significant pace (say, 1kg/month or faster), and assuming it's not just a correction after a short stint of overeating (as in, it's more than losing 1-2kg you put on over Christmas) - then some feeling of hunger is inevitable. Losing long-term accumulated weight is going against your body's "wishes" (especially in the lipostat model, where your body has a set fat% equilibrium that it seeks to maintain), and hunger is an inevitable response to that. How much hunger you will feel can be controlled by better food choices and so on, but you will have to also get used to feeling some level of hunger.
This is very true, exercise is very important for health regardless of its effect on weight.
> For cardio sure but for weight training you're burning calories and tearing muscle fibres to increase size/strength.
True, but you need to spend even more time to rack up 800 Cal worth of exercise by weight training compared to doing cardio, as a beginner or even an intermediate level gym goer.
It is also true though that weight training, if you actually successfully build muscle mass, can significantly increase your BMR and thus help with losing weight in that way, even if you're not spending hours or lifting hundreds of kilos at every session.