I will now attempt to translate Princhester’s comment into language which Squink might understand: Yes, it does require energy and calories to accomplish vasoconstriction. It also requires energy and calories to close the doors to your house. But both of these are easier and require far fewer calories than it would take to replenish the heat loss which would occur with open doors or without vasonconstriction.
Thank you, Princhester. I think I’m finally getting it.
Give that man a cigar. And good morning. Has it been 9 hours already? Nearly bed time for me.
Squink already understands. Princhester said this:
which is just flat our wrong. You will burn some calories in order to warm up a chunk of ice in your belly. We’re not talking a lot here; the 116 Calories per liter I mentioned in post 36 amounts to about 5 Pringles brand artificial potato chips. You might burn somewhat less than that 116 Calories by an efficient closure of some of the doors and windows of the circulatory system, but that is irrelevant to the fact that you will burn more than zero Calories warming up the ice.
To answer the OP:
It’s a hell of an inefficient way to lose weight, but you can diet by eating ice.
Some perhaps. I’ve seen precious little to support the proposition that it will be significant.
But anyway, keep the bald citeless assertions coming. Post your assertion about 6, maybe 7 hundred more times and I’ll be convinced. Maybe use some interesting language. Try saying “You vill burn some more calories”. Point at me assertively as you say it.
Just to make sure we’re on the same page, you do realise that I know that calories will have to be burned to warm the water, and what I’m querying is only the proposition that they will be calories that wouldn’t have been burned otherwise?
Claiming it works like that runs you afoul of Maxwell’s Demon.
Before you eat the ice, your body is at a steady state with respect to heat production and heat loss. Ice perturbs that steady state. You must burn calories to deal with the perturbation, and the calories you had been burning won’t be enough because they were already balanced in a steady state against the environment.
Thinking otherwise is a very common misconception, and leads to trouble like the endless stream of “Most Efficent Home Heating Strategy?” threads.
So does vasoconstriction. I don’t know if you’ve caught on that it’s a matter of heat transfer being reduced. The system changes that, not energy consumption.
Suppose I have a roaring bonfire in my living room. I feed it a constant number of logs, to maintain the house at a comfortable temperature. I usually leave the doors and windows open as well. Someone dumps some ice onto the fire, dropping the heat output. Now, there’s several ways I can get the house temperature back to comfortable. I can increase the rate of log consumption. Or I can go close all the doors and windows.
All the evidence produced so far indicates that in general, it’s the latter that happens in the human body.
Sure, by using energy, burning calories. The return to a steady state takes energy that wouldn’t otherwise be needed. You can’t use the heat generated ij maintaining the pre-existing steady state to do work, you’ve got to burn some extra calories to do more useful work.
Okay, consider this scenario: We have a couch potato sitting on his couch, doing very little besides breathing, circulating blood, and exercizing his thumb on the remote control. All that work does require some small amount of energy, and so his body is also metabolizing some stuff to produce that enregy requirement.
Suddenly, out of nowhere, WHOA! He’s drinking a glass of ice water! Brrrrr! … and the body temperature drops a couple of micro-notches. And the body says, “Hey! I gotta get my temp back up to normal!”
Yes, this is a point we all agree on. This takes energy that wouldn’t otherwise be needed. But it doesn’t require energy that wouldn’t otherwise be created.
Wrong. That’s not the only solution, and Princhester’s evidence says that the body actually solves it a different way.
Consider this analogy: You have a job that pays a fixed amount every so often, and it covers all your expenses okay. Suddenly, an unexpected expense comes up. What do you do? One solution is to get a second job. And if the unexpected expense is very large, it might be your only option. But if it is small enough, you might be able to simply cut back on other expenses. For example, don’t waste so much water while you brush your teeth or wash the dishes. Then, next month’s water bill will be smaller, and you’ll have the money for that unexpected expense.
Similarly, just like you don’t need to get another job to cover a $2 expense, you also don’t need to burn extra fat to warm up from a drink of cold water. All you need to do is a little vasoconstriction. (I’ll repeat: A little vasoconstriction. Yes, it will require a couple of calories to do it, but not nearly as many as it would take to burn more fat.) It’s like putting a sweater on. The energy that the body is already producing anyway will stay in the body longer, and instead of getting radiated out and wasted, it will eventually return you to the steady state without burning any extra calories.
Nope, you can’t melt ice for free, no matter what path you take to do it.
Already answered by Princhester in post #45
Did you read post 46 Keeve?
Try looking at it this way. Assume you’re right, and you can melt a kg of ice in your belly with no additional usage of calories.
OK, now let’s eat a second kilogram of ice.
You haven’t used any calories to melt the first kilogram, so you’ve got the same number of calories to melt that second kilogram.
Repeat as needed, and pretty soon you’re either melting a mountain of ice on a 2000 Calorie per day diet, or you’ve frozen to death because you can’t produce enough heat to melt all that ice water.
Which is the plausible outcome in the real world?
-The zero Calorie solution must break down somewhere, and what better point to stop working, than with the ingestion of that first milligram of ice?
I would say that the better place for it to break down is when the ‘passive’ thermoregulation mechanisms (peripheral vasoconstriction, putting on a sweater, moving out of the wind and shade) are no longer sufficient to maintain your core body temperature above a certain threshold for a certain amount of time. After that point, when you start to shiver, you will actually be burning calories just for the sake of keeping warm. Not with the first ice chip.
Look to that thread I linked to on exercise in cold weather. There’s a whole lot of thermogenesis that goes on before you get to the point of shivering.
Or, take a look at this article: Does Non-Exercise Activity Thermogenesis Contribute to Non-Shivering Thermogenesis?
Why?
What should we take from that article? It is a report on an experiment that showed a null result. There was no increase in physical activity as the temperature dropped.
You need to read up your own cites. The point at which you are going wrong is contained in the very thread to which you link and is made by none other than Una Persson, who you rightly regard as an authority.
What seems to be bothering you is the idea that unless the rate at which calories are being pumped into the system increases, the ice can’t be warmed because there are no “extra” calories to do so since the system was in steady state with calories burned and heat liberated balanced off against heat lost to the environment. You are concerned that I’m attempting to get something for nothing.
The factor you’re not taking into account is that rate of heat loss of a body through convection and conduction varies with the temperature difference to the environment. So that if you decrease the temperature of a body (or just increase the insulation of a body), you will reduce it the rate at which it is losing heat. So if you introduce something cold to the body its temperature will reduce. After that, while the heat input will remain steady, the heat loss will fall. This “frees up” some heat to heat the body back to the heat it was at before, at which point it will go back into steady state.
Adding insulation has the same effect.
Don’t believe the rate of heat transfer to the environment drops with reduced temperature differential? Well, here is a quote from Una, who you correctly hold up as being an authority on this sort of thing (substitute “body” for “house”, obviously) from the thread to which you linked. Take particular note of the last line:
The reason less heat is lost from the house is because when the house is cooler, the walls are cooler and there is less temperature differential to the surrounds.
That’s the short version. Here’s the long version:
Imagine a box with a heater in it. Throughout the examples that follow, let’s imagine the amount of heat being put out by the heater never changes, and that the environmental factors (temperature, breeze etc) never change.
Now, over time the box will heat up and go into a steady state. It will reach that steady state when the rate of heat convecting and conducting from the outside of the box walls is equal to the amount of heat being put out by the heater. This is State A.
Now imagine that you open up the box, and you put in a cold brick, and then close it. What happens now? Well, now some of the heat that was before going into the air in the box, and thence to the box walls and thence to the environment starts going into the brick. The temperature in the box correspondingly drops. The temperature of the outside of the box drops. Now pay close attention here, because this is where your basic error is occuring. The temperature differential now between the outside of the box and the surrounding environment becomes less. Therefore the amount of heat being lost to the environment drops
Where does the heat in our box that was being lost to the environment when it was in State A now go? Into the brick, of course.
Next step. The brick warms up. It keeps warming up till it is the same temperature as the air in the box, at which point it stops absorbing heat. Where does the heat that was being absorbed into the brick go? To the air in the box and thence to the walls. The temperature rises till the temperature of the outside of the walls is back to that which it was before the brick was introduced, and we are back to State A again.
What could be done to speed up the warming of the brick? Well, at the same time as we add the brick, we could increase the insulation of the box by (say) lining it with sheets of polystyrene. What does this do? Slow down the rate of heat transfer to the outside of the box. What does that do? Increase the amount of available heat inside the box, thus warming the brick faster. What happens next? Well, once the brick reaches the same temperature as the air in the box and stops absorbing heat the temperature in the box will rise. This will cause the rate of transfer of heat through the polystyrene and box walls to rise (see **Una’s ** comment above) because of the greater temperature differential, and eventually the outside of the box will reach the same temperature as at State A, and steady state will be reached, albeit that now the temperature inside the box will be higher. Or, we could once the brick reached temperature take the polystyrene lining out, and the box will be at State A again, but now with added warm brick.
You ask above what happens if you keep taking in iced water. Well, in the box example if you put a heap of supercooled bricks into the boxthe temperature in the box would drop right down and consequently the outside of the box would cool. Correspondingly, the rate of heat transfer would drop. The heater would eventually warm all the bricks, and you’d be back at the start.
If you instead made some poor soul drink gallons of ice water, he’d get very cold. He’d shiver a lot and burn extra calories. No two ways about it. Vasoconstriction has its limitations in a body where core temperature can only be allowed to vary so much, and the amount of heat available without burning extra calories is limited.
I have never for a moment said that it is impossible to make yourself burn more calories by drinking ice water under any conditions. If you drink enough, or do it when you’re already cold enough, you’ll burn extra for sure. All I’ve said is that for reasonable amounts of ice water, and under reasonable, comfortable conditions, there is no direct, easily calculable relationship between the ingested cold mass to be warmed to body temperature and the additional calories burned by doing so, as Cecil and numerous others glibly suggest, because vasoconstriction confounds the calculation.
You said the number was zero. You can decrease it from 116 kcal/kg, but you can’t hit zero. To do so, you’d need a system that responds perfectly, and there aren’t any such systems in the real world.
My underlining.
Which parts of the above did you interpret to mean “zero” exactly?
Here you are in post 30:
Do you not see your implication of zero additional calories there?
If you’re backing off on that now, good for you. I’ll consider ignorance fought.
I’m not backing off anything. I have posted on this subject up hill and down dale for years, and my position overall from multiple statements made in this thread and others linked off it is quite clear. Indeed my first two quotes above are from my very first post in this thread and make it absolutely plain that my position was not absolute. But I guess isolating one ambiguous comment from later in the thread and interpreting it in a particular way so you can pretend my position was other than what it clearly was, so you can save some face by suggesting I needed correcting is understandable.
And let’s face it, you certainly have some face saving to do, given that up till a couple of posts ago you were asserting that it was impossible to raise the temperature of water without burning additional calories, a position that you’ve now realised is (on the basis of your own cites, no less) dead wrong. That in fact probably some additional calories are burned (no real world system being perfect, as you say) doesn’t save you from the fact in theory the water could get heated without burning additional calories. Up until a couple of posts ago you were arguing this was simply impossible on the basis of (wrong) “simple thermo”.
But by all means do post again attempting to suggest that it was my ignorance and not yours that has just been fought: although whether you’d want to do so and thereby give me no option but to rub your face in it again is a question I’ll leave to you.