I'm an MD. I don't remember this specific piece of information being mentioned during my training. However, all the information need to reason about it was included...
What really blows my mind is how many people get it wrong, including my colleagues and especially dietitians ("they had one job").
> including my colleagues and especially dietitians
That is fairly astounding... I'm a paramedic and while I don't recall talking about this specifically, the answer was immediately obvious from the (comparatively limited) amount of A&P training we receive.
Yes, but the only part of the fat that transfers to the water is the hydrogen, which weighs just slightly more than nothing (perhaps TFA covers this... I didn't read it...)
And the reverse biochemical process is equally misunderstood. I used to teach high school Science and everyone thought a tree's mass came from the soil.
This is not incorrect, a tree's mass does come partially from the soil, it's just that the majority comes from the atmosphere. It's not like the tree just puts out roots cause it likes the feeling. Where do you think all the water mass in a tree comes from?
I would more chalk this up to too little biology, too late, for people to learn well. And, frankly, it's not something everyone NEEDS to know; misunderstandings are not the end of the world.
I think many people interpret it as "Why do I lose weight?" or even "Where does that fat go when I lose weight" and answer correctly: your body uses up your fat stores as fuel when there's no easy sugar available. Calling that a wrong answer is a bit unfair, there's nothing technically incorrect about it.
However, that's not what was asked - the question is where does the mass go? After all, if you light a fire inside a box, the box doesn't get lighter.
The trap is that there are by-products from the chemical reactions which have to go somewhere, and that somewhere is typically through respiration (and excretion).
I thought it was ironic to find this statement in an otherwise solid article:
"(So wrong. Mass cannot be converted to energy except through nuclear reactions)"
This is, of course, wrong. All energy has mass. A charged battery has more mass than an empty one. A chunk of fat weighs more than all of the byproducts that come from metabolizing it.
It's almost true, because the conversion factor between mass and energy is huge, so the change in mass for more mundane quantities of energy is far below what's reasonably possible to measure. But there's nothing special about nuclear reactions aside from the quantity involved.
Great calculation, wrong conclusion. Exercise does not cause any significant weight loss, of course unless you are doing it 6+ hours a day. All major weight loss typically comes from controlled diet. This means eliminating non-complex carbs. This is a major misconception in general public and people just don't seem to get it. Exercise helps build muscles, metabolism and endurance, but for weight loss your only practice option is diet control. The major energy expenditure for body is not walking or moving but just staying warm and brain. The reason people gain weight is not lack of exercise but because they eat all these fast burning carbs that rapidly gets deposited as fat instead of getting used up for body's energy need. If you want to lose weight rapidly, just make sure to add lot of fat and protein in your diet with as little carbs as possible and watch the weight drop.
Here's a meta analysis that says that exercise does help for weightloss. It also agrees with you about the health benefts of exercise, and that people get those health benefits even iftheir weight doesn't decrease.
But it clearly says that exercise combined with diet changes is better than either alone.
> The results of this review support the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost.
any particular reason you chose 6 billion? (Just easier math?)
While I thought the current estimates were closer to 7.1 billion. Though I doubt those 7+ billion people eat 2000 calories per day. When you consider how many people are starving in the world, I am not sure if its offset by the overeating overweight nations.
Well, when used as an analogy, it doesn't have to be correct. But still, you're right.
While looking this up, I came across the craziest sentence in the Wikipedia article:
"German physiologist Friedrich Goltz demonstrated that a frog that has had its brain removed will remain in slowly heated water, but an intact frog attempted to escape the water when it reached 25 °C."
Apparently this isn't quite as crazy as it sounds, as the brainless frogs still exhibit some reflexes, to the extent that they'll jump out of hot water. But still, it reads like a study in "WTF did you expect to happen?!"
Often we all assume something and so no one really investigates it properly. Science must concern itself with things we think we know are a priori truths in order to provide a solid basis for building on.
That said Goltz experiment seems quite reasonable to me, ~"do frogs have non-brain based reflexes that react to temperature?", ~"do frogs react to absolute temperatures or just changes in temperature".
I'd like to point out that how many calories they consume does not necessarily affect the number of calories they burn (excusing starvation mechanics since I have no idea how that works).
What about rubbing? I mean, when you rub against stuff (even wind), some of your cells get taken off. I'm all for peeing, pooping, and breathing, but how much weight do we lose just through simple friction? And if it's significant, should we employ more rubbing in our daily exercise routines?
Your epidermis grows at a specific rate and will not really grow faster if you remove it. If you remove it faster, you will develop scar tissue, which is not desirable.
An interesting way to remove fat is lactation. It is the only biologically "native" way to directly remove lipids. Unfortunately this is only available for lactating females.
Sebaceous glands function in a similar manner. Holocrine secretion where you basically expel the cell entirely. Not surprising really since breast tissue is essentially modified sweat/salivary gland.
IANAD, but I don't think your are going to change the cell division rate in the skin that way. You will just end up performing trauma to your skin if you remove the upper layers of the skin (past the stratum corneum I think) faster than it can grow back.
your skin is your body's largest organ and one of the fascinating aspects of it is just how rapidly it both sheds or is sloughed off and just as quickly replaced
I'm proud to say that I got it right, after a brief "urine" moment, but I think it's only because I had watched the Veritasium segment about where trees come from, way back when.
A quick proof that the answer isn't "you poop it out": when you work out more, you don't poop more. (You do, however, breathe more, which points towards the correct answer.)
There's a nice Veritasium episode wherein he asks people on the street where a tree's mass comes from: https://www.youtube.com/watch?v=2KZb2_vcNTg (This isn't just one of those "let's laugh at how dumb people on the street are" videos; it's done explicitly as a learning exercise. His PhD looked at how addressing misconceptions and going from there to correct explanations works much better than simply providing explanations: https://www.youtube.com/watch?v=RQaW2bFieo8 )
I thought of it upon seeing the first chart in the BMJ article.)
>It Gets Converted to Energy (So wrong. Mass cannot be converted to energy except through nuclear reactions)
This is not true. There is energy in chemical bonds, and that energy is released when the bonds break. When you burn gasoline, the mass of the resulting molecules adds up to less than the mass of the original gasoline. A tiny, tiny fraction less, but still less. Because there was energy in those bonds, and energy has mass.
It's wrong in another way, too, because even in nuclear reactions mass isn't converted into energy. Mass is mass, but energy also has mass. No mass is lost in a nuclear (or chemical) reaction, it just goes somewhere else. There is no "conversion" going on.
I was thinking about this a couple of weeks ago, expiration that is. This question raised itself and I've not focussed on answering it yet - if you breathe more then, like forced breathing, can you accelerate carbon loss [beyond that expected by the increased exercise involved in such breathing]; like fanning flames I guess.
Thinking now I suppose an [close] equivalent is probably can you increase carbon dioxide production by increasing oxygen saturation of the air inspired?
There's probably enough in that idea to sell oxygen masks and little tanks and a book for a new fad 'diet' ...
Not sure that would be true... the body is producing a set amount of CO2. Breathing faster would expel it more quickly, but not change the total amount, correct?
I suppose the act of breathing itself would burn more calories, but it isn't the most challenging exercise, not to mention the dizziness mentioned already.
I'm going from a position of ignorance wrt how breathing works at the molecular level – how does the carbon arrive on site (which specific location) to combine with the oxygen, what membranes are involved, what vapour pressures and saturations might be pertinent. Ergo, I hadn't addressed the question as yet. Basically I'm asking is exertion the only limitation on the CO2 production.
[1] answers a lot of this.
Again with presumptions from biological ignorance, in low oxygen environments it seems we can't "burn" so much food, so oxygen saturation is definitely a limitation. Also we know that oxygen saturation varies, so even if STP oxygen percentage of air is the optimum sometimes we'll be sub-optimal - how does the body cope then?
[2] appears to answer that one.
What I take away from that, wrt my enquiry, is that under increased breathing [hyperventilation] renal compensation can kick in to combat the alkalemia caused by the respiratory alkalosis [reduction of available H+ ions in the blood, ie alkalination or increasing of pH] by extracting extra-cellular fluid bicarbonate [HCO3-, see [3]] and excreting it in urine.
Now I'm moving back up the pathways, is renal compensation deleterious (and at what point is that true). Does low level alkalosis with renal compensation cause an increase in removal of food products from the body?
At least it seems that we now have created an increased carbon removal by excreting HCO3- in urine!? [how much?]
So is there an increase in breathing frequency that maintains normal function, not "hyperventilating" (in the common usage of the term, that makes you dizzy), that doesn't cause harm? The question still stands I feel.
Also can you do something else that causes acidosis and cancel it out by increased breathing?
Apologies again, I'm clearly fumbling around here but I've not studied biology since I was 13 (decades ago).
I believe that encouraging aerobic respiration (maintaining high levels of O2) would be less efficient if your goal is weight loss.
When your cells are breaking down sugar into energy, if you have enough oxygen readily available then you can extract more energy per molecule of sugar. If you're burning sugar anaerobically, then you won't be able to make the full use of the sugar, and thus the byproducts will get excreted with less work required.
Also, I was mistaken somewhat, the byproducts aren't excreted, they're reprocessed in the liver back into glucose, but this requires extra energy. So it's less efficient than aerobic respiration, but not by as much as I believed.
I think oxygen toxicity is pretty well know, what I was musing over was whether through a slightly elevated breath frequency, or slightly deeper breathing, one could have more oxygen available and so increase CO2 production. If instead of 100% oxygen one breathes 22% (vs. 20% in normal air IIRC), what then?
Someone else has noted respiratory alkalosis as a limiting factor, but that again is seemingly an extreme.
Just asked my wife and daughter what the answer was, and they both thought you excreted the mass. Then I asked my son, who is home from Uni, studying a Biology degree, he said it was released as energy. FFS.
Please embrace my willingness to look foolish, I really want to be able to explain this properly; can someone explain to me why fat doesn't get changed into energy, and disappear through heat?
>can someone explain to me why fat doesn't get changed into energy, and disappear through heat?
Fat is some complex molecule made up of a bunch of carbons, hydrogens, and oxygens. Where do you think these atoms go?
The short of it is the fat molecules are turned into other molecules (which gives you energy) with the addition of oxygen, and the byproducts (water and co2) are expelled as a byproduct.
A simple analogy would be combustion in a car engine. The fuel doesn't disappear through heat. You get a number of byproducts (mainly CO2 and water) coming out of the exhaust car.
How would respiration be surprising to anyone with a high school level education?
> This analysis makes it clear why exercise is so powerful in the weight loss equation.
There are many reasons to exercise, but it's quite clear weight loss isn't one of them. I mean, you need to exercise to get your abs to pop, but not being a lard-ass is totally about avoiding excess calorie intake and exercise really doesn't enter into it. People don't realize what a trivial amount of calories working out burns.
>People don't realize what a trivial amount of calories working out burns.
I think it's more that people don't realize how stunningly high calorie counts for "bad" food can be. Like a cookie might take 20 minutes of exercise to burn off the calories, but that's more about the cookie than about the exercise.
Even burning through a single Granny Smith Apple takes ten minutes. Half a cup of dried cherries, dried pears, or raisins, would take over 20-25 minutes. All of these are pretty natural.
Undeniably there are artificial foods with insanely high calorific levels for either their volume or weight. But all foods are inherently hard to burn off via exercise. Some are just worse than others.
Partially because those foods aren't really 'natural'. They are the result of 1000's of years of human selection for sugar and carbos. We've genetically engineered nearly every fruit and grain, the hard way, by crosspollination and grafting and selection through the centuries. We've made them very calorie-laden, because that helped us survive in harsher olden times.
Yes, taking a sweet fruit and removing all the liquid leaves you with something that is remarkably unhealthy by weight, despite being "natural." But that just means that eating a lot of dried fruits and nuts and such is not a great diet choice.
It's not clear to me. Exercise is a good way to burn calories. But perhaps more significantly, if you do it regularly, you will burn more calories even while at rest.
Exercise for overweight people is important for the health benefits which exist even if no weight is lost. Exercise does help people lose weight. It's probably important to manage expectations - exercise alone is not as good as diet change and exercise combined.
> The results of this review support the use of exercise as a weight loss intervention, particularly when combined with dietary change. Exercise is associated with improved cardiovascular disease risk factors even if no weight is lost.
The health benefits of exercise come from "conditioning" sessions, not watching some ill-informed calorie meter. Exercise makes you fitter and healthier by hitting progressive overload. Meaning it has to be difficult, nay unpleasant, and thus done rather infrequently to allow plenty of recovery time.
cbass.com has this stuff dialed in. One im-gonna-puke strength session a week and one difficult endurance "cardio" session makes a ton of sense to me, when you take in the literature. Much more and exercise starts to look like a net negative in many ways. Suggesting to a fatty that they jog five times a week is at best a waste of time and at worst actively harmful.
I posted a link to an internationally reputable organisation who do gold standard meta analysis.
You? My neuro-atypicality means I geniunely don't know if you're trolling and yours is a parody post, or if you actually think cbass.com - a comercial site selling get fit quick dvds and books - is a reputable cite.
One question: if they have it "dialed in" why are they selling ten different books?
Your gold standard meta-analysis is useless for the purposes of someone actually trying to lose weight. It merely takes the position that diet and exercise produce better outcomes than either alone. That tells us nothing about which has the more powerful effect.
Anybody who's actually tried, and succeeded, in losing weight and keeping it off will tell you that diet is way more important than exercise when it comes to fat loss. Exercise absolutely produces health benefits, but they are largely orthogonal to the ones produced by changing how you eat. If you can do one but not the other, then diet.
Most people with a lot of weight to lose have willpower problems, that's why they have a lot of weight in the first place. Not all, but most. These people are better served conserving their willpower and taking more effective courses of action than the one they can't take. (both diet and exercise)
As I understand it, the amount you can increase your caloric burn rate through exercise is generally much smaller than you can decrease your caloric intake through dieting. The result being that, as some fitness communities say, weight loss is done in the kitchen.
The resting metabolic rate thing is a myth. In fact if you google metabolism myths that's one of the biggest one. Just going off memory a pound of muscle burns like 10 calories per day while a pounch of fat burns like 5. So replacing a pound of fat with a pound of muscle nets you 5 calories burned per day. Not exactly amazing considering you need to burn about 3,500 calories to lose a pound of fat.
Also consider... I'm a 33 year old 215lb man. An hour at the gym lifting weights is about 340 calories, or approximately the amount of calories you get by drinking a couple glasses of soda at lunch and dinner. You need 10 trips to the gym or 10 days without soda. Assuming you go to the gym 3 days per week, that's 3 weeks of exercising compared to 1.5 weeks of drinking water instead of soda.
It's really easy to burn an additional 500+ calories with exercise, which is very significant. Of course it's not a substitute for a proper diet, but it can be a huge factor in weight loss.
500 calories in one session? Or over a whole week? In one session it is definitely not "easy." In a whole week it is.
If you walked at 2.5 MpH and weighed 160 pounds, it would take you two and a half hours to burn your 500 calories. To me 2.5 hrs is not an "easy" workout. Somewhere between medium to hard (depending on fitness level).
A single Big Mac is almost 500 calories, two snickerdoodles are more than 500 calories on average.
> Of course it's not a substitute for a proper diet, but it can be a huge factor in weight loss.
That's just not true.
A single combo from McDonalds could set you back an entire weeks worth of exercise, literally. If you exercised for an hour a day every day, it only takes a single meal to undo most of that weight loss.
PS - Exercise is, of course, very important for overall health and a long life. Nobody is arguing otherwise. But for weight loss? Heck no. The maths simply doesn't work at all.
It depends on whether you consider intensity or duration to determine how "easy" a workout is. Sure, 2.5 hours is a lot of time to invest, but walking at 2.5 MpH hardly seems strenuous enough to qualify as exercise.
A 160 pound person could burn 500 calories in ~40 minutes jogging at a 10 minute per mile pace, and could easily offset a Big Mac in a single day's exercise (not saying that the person should use this to justify eating a Big Mac).
Not really. Probably even a bit the opposite. If you exercise hard daily the resting metabolic rate actually drops some as an adaptation to conserve calories: exercise induced hypothyroidism. Pro level cyclists have to count calories to keep their weight down and they don't eat nearly as much as you'd think.
Muscle mass preferentially burns fat, so you get a very small metabolic edge from having some extra muscle, but not much. Adipose tissue also burns a great deal of calories, believe it or not, so getting really fat is a good was to increase your metabolism. This is why when obese people start restricting calories the first 30 pounds or so pretty much melts off with not much difficulty.
This is of course trivially verifiable. To burn 1000 calories in 45 minutes if your body is an average 25% efficient requires around 385W of continous power output. The majority of women will struggle to output this for a mere minute while most men won't last 5.
So no, your 45 minutes of HIIT isn't burning 1000 calories, and if calories are your goal, you would obviously not be doing HIIT in the first place (what's the point in getting nauseous when you can just produce these steady watts).
(That said, I still heavily disagree with the grandparent; exercise is as much part of a diet as is calories in / out. If you can do 150W for a grand total of 5 hours every week, that totals 2500kcal or more than an extra days worth. For many people, time spent exercising is also time spent not sitting idly in front of a TV and eating.)
In any case, the "cycling" bit is somewhat of a smoke-screen; it just so happens that it's most easily measured and objective data has long been available through power meters. There is no free-lunch, regardless of the particulars of any sport.
(I should however probably clarify that the power numbers quoted above are mechanical power as measured during cycling, which is pretty much the only sport that even has ways of measuring power reliably)
It would be interesting to know the particulars, but in general you hook up a cyclist up to a dynamometer and a ventilator, and you measure both the amount of work done and the amount of CO2 produced. I say "cyclist" because they're the easiest ones to hook up to a dynamometer.
That's absurdly high. If you can sustain that level of activity, you likely don't have the weight problem in the first place.
I'm a couch potato, I can burn about 300 cals per half-hour (according to the stationary bike machine or elliptical). In my better days, that was up to 350 cals per half-hour, I was quite fit but not athletic.
The mass of a molecule is the mass of its constituent atoms plus the mass of the bonds between them. When those bonds are broken, the system loses the amount of mass one would expect given e = mc^2.
Note: this amount of mass is very small and so is typically left out of introductory chemistry courses.
The mass is almost almost almost conserved in chemical reactions. By special relativity, the energy/heat that produces the reaction should come from a extremely slightly difference of mass between the reagents and the products. The difference is so small that in any chemical class and chemical application you just assume that they are equal. (http://en.wikipedia.org/wiki/Conservation_of_mass#The_mass_a... )
For example, a person consumes approximately 2000 kcal/day of food. The calculation is more complicated, because not all the energy is used. But for the sake of the argument, let's assume that the person just use all the 2000 kcal and they are lost as heat, work (lifting a heavy object , moving the air, moving the water while swimming, ... )
Using the famous E=mc^2 equation we have that m=2000 kcal/c^2 = 9E-8 grams = 3E-9 ounces. That's very small and is not useful for a diet, but it's not zero.
There are several ways that "mass" can be converted into energy. In this case we are not talking about e=mc^2. The conversion of fat cells to energy for brain and muscles should involve at the end of the day: urine (lactic acid etc.) and exhaled H2O and CO2.
Edit:
Notice I put mass in quotation marks. I am not trying to break the law of conservation of mass. Fat cells consumed will produce energy through some kind of biological process.
...isn't that just re-arranging atoms and electrons into lower energy states? The mass of those atoms and electrons doesn't change. A block of steel has the same mass at the top and bottom of a hill.
Does converting chemical bond energy into kinetic energy somehow remove energy (i.e. mass) from the system?
Does a block at rest sitting on the top of a hill have more mass than a spinning block at the bottom of a hill (assuming the rotational kinetic energy equals the difference in potential energy)?
Whether the energy leaves a system depends on the particulars. If you burn some hydrogen in a bomb calorimeter, the energy will stay inside the calorimeter. This is a "closed system". If you burn it with an open flame, the kinetic energy will warm the atmosphere. This is an "open system". The energy could end up anywhere... you can use hydrogen to launch rockets into space.
Since the energy can end up anywhere and the energy has mass, the mass can end up anywhere, too.
I don't follow how that explains why two identical objects with the same energy content should be expected to have different masses. It seems like this whole thread is trying to argue that chemical reactions destroy mass through examples of open systems that leak energy. A leaky water balloon loses mass, too but that doesn't constitute evidence that atmospheric pressure/tension/etc destroys mass, does it?
If you take a block of steel from the top of a hill to the bottom of the hill and convert all the potential energy to kinetic energy (without loss), why would the mass of the block be altered? It may well be true, but arguments based on applying the mass-energy equivalence is not the answer.
Likewise, if you start with some pool of molecules and rearrange the constituent atoms and bonds, energy must be balanced via kinetics (i.e. translational and rotational energy of and within molecules on both sides of the reaction)--why should anyone expect the overall mass to change from such chemical reactions?
Per E=mc^2, energy and mass are basically the same thing. Also, if you weight your substrates before and after and exothermic reaction, you'll see a (very tiny) loss of mass.
Yeah I know they're basically the same which is what makes this hard. And energy stored in chemical bonds has gravity just like some tiny amount of mass would. But if someone is asking for the difference between mass and energy, I wouldn't put that on the mass side.
Not technically correct. A small amount of mass is lost or gained in chemical reactions, just like when gravitational potential energy is gained or lost.
If you walk up a flight of stairs, you will be heavier at the top. If an electron changes orbital, its mass changes as well, making it heavier or lighter.
Let's calculate it. A 90 kilogram man walks up a flight of stairs, one story (3.3 meters). The expression "m * g * h" gives us the gravitational potential energy of mass "m" ascending height "h". Evaluating the formula we get 2910 joules. So how much heavier has the man become? Given E=mc^2, then m = E/c^2. As you can see, we'll be dividing by c^2, which is a very big number. The resulting increase of mass is 3.24 E-14 kg, or too small to be noticeable, but still very real: A 90 kg man ascending a 3.3 meters gains 0.00000000000003 kilograms of mass.
Chemical potential energy changes result in mass changes as well. These changes in mass are insignificant at the scale of chemical reasons, but are indeed taking place. So while it may be reasonable to simplify a discussion of chemistry by saying that chemical reactions don't change mass, in reality the changes do take place, just at a very small scale. A starting point for further research:
"Whenever any type of energy is removed from a system, the mass associated with the energy is also removed, and the system therefore loses mass. This mass defect in the system may be simply calculated as Δm = ΔE/c^2"
nit: "heavier" refers to weight, not mass. The man will actually be lighter at the top of the stairs due to decreased gravity. (R_earth / (3.3m+R_earth))² ≈ -0.0001 %
Someone else can calculate the decreased buoyancy in thinner air ;)
Q is the released energy. If you weigh the molecules before and after very carefully, you will notice that they lose weight (or mass if you are being pedantic about it). That mass loss corresponds exactly to the Q-value (through E=mc²).
Why is Q not part of the system anymore? Isn't the Q carried by the 2H₂O molecules (or the solution/matrix/whatever)? Doesn't it just represent that the energy is of a different form?
How does bond energy represent mass but kinetic energy does not represent mass? I realize Q is a different symbol in the formula, but that's just notation. The bond energies are implicit in the formula, but that doesn't mean they aren't there.
No mass is lost in this reaction. The mass of the atoms remains the same. The energy that is released is due to the difference in bond energies. To balance the equation you would need to add a Q to the other side, corresponding to the bond energies.
The molecules consist of Hydrogen and Oxygen that have equal atomic masses, either side of the equation, due to the identical numbers of protons, neutrons and electrons.
Any mass gained or lost will be due to changes in bond energies, and the corresponding emission or absorption of photons that change the energy states of the electrons in the bonds.
Putting a Q on the left hand side would be an error. Q indicates that the energy is not bound in the molecular configurations.
If you measure the mass of a quantity of water accurately enough, the mass will be lower than the mass of the equivalent amount of hydrogen and oxygen gas. The difference would be so small that our most sensitive instruments would not be able to detect it.
Likewise, in a nuclear reaction, the only thing changing is the nuclear binding energies of the protons and neutrons. However, since the energy involved is many orders of magnitude higher, our instruments are sensitive enough to detect the difference in mass.
Speaking in generalities yes, but TECHNICALLY stuff that contains more energy is heavier too. But given that most enthalpies are in the kJ/mole range and most moles of things are pretty heavy relative to 9e18 (the speed of light squared) that you might as well round it out and say "no mass is created or destroyed in an ordinary chemical reaction"
I just want to say as someone with a degree in physics that this commenter is correct. Mass and energy directly relate through E=mC^2. If you remove energy (and "just" energy) from a system, it now has E/C^2 less mass.
Example:
You have some fissible material that undergoes a nuclear reaction in a closed system and the reactants turn into products with lower mass.
The mass of the system doesn't actually go down until/unless the system cools down.
edit: The above commenter is still being pedantic though
Conservation of mass at the scale of biological reactions is true enough though. I also didn't like this phrasing, but it leads into talking about the byproducts of metabolism, which was the whole point.
And, it is contradicted just a few paragraphs later. Sugar (and fat once it has been broken down) is burned. The statement becomes much more sensible (and less of a straw man) if we say "mass is burned". Works for steam engines. Works for people.
I don't know why the parent thinks it's wrong, but I think it's wrong because it's a statement that works at the wrong level of abstraction.
Yes, it's quite true that in physics, mass cannot be turned into to energy. But the article's not talking about physics; it's talking about biology, and in biology, fat can be turned into energy --- that's why your body makes it.
Yes, of course it's not a nuclear process. The fat's metabolised into energy and waste products, which are excreted mostly through the lungs. Also via the skin, urine, faeces and any other bodily fluid --- one byproduct is water.
'It's turned into energy' is actually the right answer if you're thinking about biology. It's just not a complete one. The article would have done much better to have instead said 'you're right, but' and then gone on to explain, rather than just saying 'if you think this you suck'.
Also the idea that exercise has a huge affect on mass loss is also pretty wrong. If you've got a large amount of weight you need to lose, the only needle exercise is going to move is your willpower, downward. Making it difficult to stick to what works, which is eating less. Shedding mass is way more about building willpower and good habits than it is about playing metabolic tricks.
The picture changes when you're down to those last few pounds. To get those off, you have to keep up the reduced caloric intake, and you also have to exercise. If you slack off on the former, you'll gain weight back. If you don't exercise, you won't lose any fat.
Building habits and willpower is a journey that takes at least a year and involves changing your relationship with food. To a large extent, we see food as entertainment, it takes a long time before our subconscious minds' adjust to thinking about it as fuel. Inherent in this is replacing that hole left in our psyches where food entertainment used to be with something else as entertainment.
It was a whole year after I started dieting before I started looking at salads as a perfectly acceptable lunch, perfect for getting a feeling of fullness without blowing up the calorie meter. For a long time I played this game of trying to get the most value out of my calorie budget, still mind thinking of food as entertainment.
I did intermittent fasting, which was effective at helping me lose weight but not at keeping it off because it didn't solve the food-as-entertainment issue. Once I got down to a more reasonable weight I stopped, and before I knew it I was fat again, though not nearly as fat as before. I hadn't stopped thinking of food as something to cure boredom with.
I eat better than I ever have, and look more youthful at 31 than through most of my twenties. Ironically, I feel I also enjoy food a lot more than I used to. I taste it better, I find it more interesting. In a Buddhist non-attachment sort of way.
Nice try. Everyone knows that there are nuclear reactions that take place in the digestive tract and that we poop out small unobtanium lumps which are gathered in the night by underpant gnomes. that's the unknown middle step revealed.
I'm an MD. I don't remember this specific piece of information being mentioned during my training. However, all the information need to reason about it was included...
What really blows my mind is how many people get it wrong, including my colleagues and especially dietitians ("they had one job").