Hot food = more energy for your body?

In summary: its just a guess) in summary, if you take the same food, same amount and everything except one serving is heated and another is not, the person eating the heated serving would get more nutritional value from it in the form of more energy.
  • #1
pivoxa15
2,255
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Is it true that if you take the same food, same amount and everything except one serving is heated and another is not. Would the person eating the heated serving get more nutritional value from it in the form of more energy? This comes about from the larger potential energy stored in the bonds of the food that has been heated.

An anology on a much larger scale would be dead leaves that gets buried or squashed underground and over million of years serve to become fossil fuel. The vast energy does not come from the leaves themselves but from the potential energy accumulated by converting gravitational energy (through squashing) into molecular energy stored in the leaves to become a fuel.
 
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  • #2
I really doubt it.

My guess, (and since I'm in NO way any kind of expert in the area, that's all it'd be, a guess), is - no.

The reason I say that is this. By the time your body has broken down the material you ingest into things like sugars etc, that it can actually use to derive energy from, that material has been in your body MORE than enough time to cool back down to (or, in the case of things like ice cream, even warm up to) your core body temp.

By that I mean - although the *process* of digestion starts as soon as things hit your stomach (in fact arguably as soon as you start chewing it), that process involves MUCH more than just instantly sucking chemical potenial energy out of the material you ingest. Your stomach is doing one HECK of a lot of "prep work" breaking things up, followed by your intestines doin' their "thang", etc., all just to get that material to the point where your body can derive energy from it, and by that time, it's been in there quite a while, MORE than enough time to cool down to, or warm up to, your core body temp.

Make sense?
 
  • #3
I would also say that for the most part in terms of practical reasoning, it doesn't matter. BUT theoritically when you digest foods of different temperatures of course there is an effect.

If the food is too cold, it can do several things.
(1) extremely cold or hot food will damage the cell lining of your digestive tract which includes your throat, esophagous, stomach etc. The damage will induce repair which "costs" energy.
(2) cold food will steal heat from the body's own physiologically maintained temperature and will therefore require energy indirectly to return to normal physiological temperature (known as homeostatic temperature/conditions)
(3) food that is a little warmer will then the body to the point that it doesn't damage, will minimize heat loss that occurs in (2) and will therefore be more energy efficient then cold food.

But in terms of the molecular digestive process, your body equilibriates the food to the tempearture of your body fairly quickly.

This also occurs with the air you breathe. When one exhales the air's temperature has increased in a short period of time.
 
  • #4
I would say no but for a different reason: Your body uses a more structured form of energy to work, chemical energy from the foods you eat.

My suggestion is that your body would get more energy, but it would still just be heat energy, and a 'hot muscle' is not necessarily healthier one. Not that the heat would get to any muscles.
 
  • #5
I would say that heating food can induce certain chemical changes. Some chemicals may effectively burn. Others such as sugar will decompose into simpler and more stable chemicals. I also suspect, and I'm not sure about this, that large molecules such as proteins and vitamins will break down. The effect of this is that cooked food will be less nutritious. Also the broken down chemicals will not have lost their energy. Thus this energy can no longer be absorbed by the body.

That being said, if you are at some very high altitude, in say the Himalayas, and made the mistake of wear a t-shirt and shorts, you may benefit by drinking boiled yak's milk. If the milk is hot, you will loose significantly less energy through shivering.
 
  • #6
From what I've read, I would expect that mammals or other endotherms in a gernallly cold climate would need less total calories to maintain their weight if their food was warm. The warmth of the food would reduce the calorie expendeture needed for body temperature maintenance, slightly. This would only apply in a cold climate.

Ectotherms (animals without temperature regulation) would probably actually need more calories with warmer food - increasing their body temperature due to the warmer food would generally tend to increase their metabolism.

For the later point see
http://www.depauw.edu/acad/biology/Websites/kevinkinney/Lab%2011B-Temperature.html [Broken]

(not sure how long this link will work, it looks like the sort of link that might disappear very quickly, but it was quite interesting)
 
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  • #7
pivoxa15 said:
Is it true that if you take the same food, same amount and everything except one serving is heated and another is not. Would the person eating the heated serving get more nutritional value from it in the form of more energy? This comes about from the larger potential energy stored in the bonds of the food that has been heated.
There would be a small indirect energy benefit to the body in the sense that the body would not have to use its metabolic heat to warm up the food to body temperature.

An analogy on a much larger scale would be dead leaves that gets buried or squashed underground and over million of years serve to become fossil fuel. The vast energy does not come from the leaves themselves but from the potential energy accumulated by converting gravitational energy (through squashing) into molecular energy stored in the leaves to become a fuel.
I don't quite get the analogy. Interesting concept though. I don't see how, thermodynamically, gravitational pressure would put that much energy into the organic matter. There just is not that much work done in the compression. Pressure definitely changes the organic matter chemically over a long time. But the energy is ultimately from the organic compounds made by the plants during photosynthesis.

But I may be quite wrong. I would like to see a source that analyses the energy input from gravitational pressure to support your contention that the vast amount of energy in fossil fuel comes from the gravitational potential energy.

AM
 
  • #8
Andrew Mason said:
There would be a small indirect energy benefit to the body in the sense that the body would not have to use its metabolic heat to warm up the food to body temperature.

I don't quite get the analogy. Interesting concept though. I don't see how, thermodynamically, gravitational pressure would put that much energy into the organic matter. There just is not that much work done in the compression. Pressure definitely changes the organic matter chemically over a long time. But the energy is ultimately from the organic compounds made by the plants during photosynthesis.

But I may be quite wrong. I would like to see a source that analyses the energy input from gravitational pressure to support your contention that the vast amount of energy in fossil fuel comes from the gravitational potential energy.

AM


Why do you think diamonds are found in nature? They are just pure carbon but recquire pressures of over 15 atms to naturally occur.

Similarly one form of fossil fuel, oil use to be carbon based matter but over millions of years, 'eventually turned into oil under great pressure and heat'.

'More and more rock piled on top of more rock, and it weighed more and more. It began to press down on the peat. The peat was squeezed and squeezed until the water came out of it and it eventually, over millions of years, it turned into coal, oil or petroleum, and natural gas.'

http://www.energyquest.ca.gov/story/chapter08.html

The law of conservation of energy says that gravitational energy must be manifested somewhere or be converted in another form. In this case, chemical energy.

I also remember from a biological lecture that the energy one gets from drinking petrol is far greater than any other source of food. Although you will probably die from doing that.
 
  • #9
From what I gather, the answer to this question is 'yes' but only in the sense of less energy loss => more energy for your body.
 
  • #10
Just to be clear, changing the temperature of food has NO effect on its nutritive value which ultimately relates to nutriment reaching the cells. Regarding thermal content, the body will regulate itself to eliminate excess heat in the case of hot food but will work to suppress heat loss in the case of cold food.
 
  • #11
When meat is heated, it gets easier to chew. Does this mean that the molecular bonds are looser? And if so, does that also make it easier to digest?
 
  • #12
Tide said:
Just to be clear, changing the temperature of food has NO effect on its nutritive value which ultimately relates to nutriment reaching the cells.
Except that many nutrients are destroyed by heating (in the form of cooking). Fresh veggies for example are much more nutritious than cooked veggies.
 
  • #13
DaveC426913 said:
Except that many nutrients are destroyed by heating (in the form of cooking). Fresh veggies for example are much more nutritious than cooked veggies.
Umm...I have read cooking certain food stuffs like carrots and tomatoes actually increases their vitamin content. :smile:
 
  • #14
pivoxa15 said:
Why do you think diamonds are found in nature? They are just pure carbon but recquire pressures of over 15 atms to naturally occur.

Similarly one form of fossil fuel, oil use to be carbon based matter but over millions of years, 'eventually turned into oil under great pressure and heat'.

'More and more rock piled on top of more rock, and it weighed more and more. It began to press down on the peat. The peat was squeezed and squeezed until the water came out of it and it eventually, over millions of years, it turned into coal, oil or petroleum, and natural gas.'

http://www.energyquest.ca.gov/story/chapter08.html

The law of conservation of energy says that gravitational energy must be manifested somewhere or be converted in another form. In this case, chemical energy.

I also remember from a biological lecture that the energy one gets from drinking petrol is far greater than any other source of food. Although you will probably die from doing that.
All that says is that pressure and heat from the Earth changed the chemical structure of the organic matter. It is not saying that the pressure and heat gave fossil fuels most of their energy. That comes from the organic compounds produced by the organisms before they died.

AM
 
  • #15
DaveC426913 said:
Except that many nutrients are destroyed by heating (in the form of cooking). Fresh veggies for example are much more nutritious than cooked veggies.

The OP's premise was that everything is the same but the temperature.
 
  • #16
Andrew Mason said:
All that says is that pressure and heat from the Earth changed the chemical structure of the organic matter. It is not saying that the pressure and heat gave fossil fuels most of their energy. That comes from the organic compounds produced by the organisms before they died.

AM

I agree totally. The chemical energy in coal and oil is just that - chemical energy. It was present before the plant material was buried.
 
  • #17
i would say yes
if youre not sweating (overheated)
the cool food would cause your body temperature to lower slightly, which your brain would sense. your brain would then tell your body to heat up, using up energy.
the thing is though, that eating hot food when youre already hot, might cause you to lose energy too, if not more. because then your body would have to expend energy sweating and replenishing that water
 
  • #18
Pervect

Great question by the way. Its very creative and fun to think about.

I think Pervect gave the correct answer.

Since there is no way for the human body to extract energy from heat for use in metabolic pathways, the only difference that hot or cold food would make is how it would heat or cool your body's core temperature. For this reason, as pervect pointed out, eating hot food in the arctic would save you energy as you would need to expend less energy conserving body heat. However, eating hot food in the Sahara desert would cause you to sweat more which (i'm speculating here) would make you expend a minute amount of energy in the form of opening your sweat glands to cool down. Not to mention dehydration of course.

Incidentally, the body metabolizes carbohydrates and extracts useful energy from them by means of the Citric acid cycle. Wherein, several chemicals are used (ie. water, Acetyl CoA, Hydrogen Phosphate, Hydroxyl ions, etc.) to transfer a Phosphate molecule around between ATP and ADP. IF the temperature at which the various reactions take place within the Citric acid cycle were elevated due to 'hot food', I would think that these reactions would occur quicker since their activation energies would be higher.
 
  • #19
Chaos' lil bro Order said:
Great question by the way. Its very creative and fun to think about.

I think Pervect gave the correct answer.

Since there is no way for the human body to extract energy from heat for use in metabolic pathways, the only difference that hot or cold food would make is how it would heat or cool your body's core temperature. For this reason, as pervect pointed out, eating hot food in the arctic would save you energy as you would need to expend less energy conserving body heat. However, eating hot food in the Sahara desert would cause you to sweat more which (i'm speculating here) would make you expend a minute amount of energy in the form of opening your sweat glands to cool down. Not to mention dehydration of course.

Incidentally, the body metabolizes carbohydrates and extracts useful energy from them by means of the Citric acid cycle. Wherein, several chemicals are used (ie. water, Acetyl CoA, Hydrogen Phosphate, Hydroxyl ions, etc.) to transfer a Phosphate molecule around between ATP and ADP. IF the temperature at which the various reactions take place within the Citric acid cycle were elevated due to 'hot food', I would think that these reactions would occur quicker since their activation energies would be higher.

Some nice biology there. On food packets, they label the nutritional value of the food, the first one is usually energy. Obviously heated food have more energy than cold food. For example, consider heating a glass of milk (400ml) for a minute in a 1000W microwave oven. A total of 60kJ would have been transferred to the milk after it has been heated. The milk contains a total of 1100kJ before heating, now it contains 1160kJ. That is a small extra amount of energy but still energy which may be valuable in some circumstances. Imaging heating the milk for 10 minutes. That would be 600kJ of extra energy - which is more than half of the milk's chemical energy. But you are claiming that our body does not metabolise heat energy. So no matter how hot the milk is, we cannot gain those extra energy in the molecules - which can be substantial for extremely hot food. Moreoever, the extremely hot milk probably will hurt the cells in our body causing the cells in our body to repair them which will cost us energy as many of already pointed out.

Imagine a time when you are very hungary and there is a large pot of boiling water on the stove. I can imagine that no matter how much of it you drink, you will still be hungary afterwards. 2 litres of boiling hot water should have 836kJ of thermal energy in it. But your body can't extract that 836kJ can it? Your body will probably spend much more energy managing all this water.
 
  • #20
pervect said:
I agree totally. The chemical energy in coal and oil is just that - chemical energy. It was present before the plant material was buried.

In that case, engines should work just as well when fed live plants?

Why is there so much more energy in fossil fuel than recently dead plants? What is this 'extra' energy in the fossils if it is not chemical energy? How is it stored in fossils?
 
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  • #21
pivoxa15 said:
In that case, engines should work just as well when fed live plants?
Not a very scientific approach. Since humans don't work as well when drinking gasoline does that mean that gasoline contains less energy than milk?

Why is there so much more energy in fossil fuel than recently dead plants? What is this 'extra' energy in the fossils if it is not chemical energy? How is it stored in fossils?
Is it that there is more energy in fossil fuel or is it that the energy is more accessible?

AM
 
  • #22
Andrew Mason said:
Is it that there is more energy in fossil fuel or is it that the energy is more accessible?

AM

This is an interesting question. I will post it in the chemistry section to see if people there can help.
 
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  • #23
Tide said:
Just to be clear, changing the temperature of food has NO effect on its nutritive value which ultimately relates to nutriment reaching the cells. Regarding thermal content, the body will regulate itself to eliminate excess heat in the case of hot food but will work to suppress heat loss in the case of cold food.
We have to be careful here in describing what exactly we're comparing. If you cook food, and eat one serving hot and plunge another serving into ice water to eat it cold but with the same amount of cooking, then the nutrient content will be the same. And, then the only difference will be if you eat enough for the body to need to expend energy to either heat or cool if the food temperature is above or below body temperature (cooling is not a passive process in human physiology).

However, if you're talking about heating food compared to food that's never been heated, then heating by itself will change the nutrient content by more rapidly breaking down the bonds in proteins and vitamins, for example. In that case, the heating reduces nutrient content, especially with heat-sensitive vitamins.

Keep in mind that, as mentioned by others, nutrient content is not just energy content. We need our energy in specific chemical forms to use it, and heat isn't one of them, otherwise we could just sit on a hot rock all day and never eat, which we obviously can't do.
 
  • #24
Moonbear,

Keep in mind that, as mentioned by others, nutrient content is not just energy content. We need our energy in specific chemical forms to use it, and heat isn't one of them, otherwise we could just sit on a hot rock all day and never eat, which we obviously can't do.

That was essentially my point. :)
 
  • #25
Remember that we humans tend to regulate our body temperature (in a cold climate) more by clothing and external means than by metabolic rate adjustments, so we might tend to overlook the extra calories obtained from the heat content of warm food. Most animals on the other hand do use metabolic rate to a large extent in terms of regulating their body temperature. It is definitely true that warm blooded animals in a cold environment need more calories from their food to maintain the same condition than if the same animal was in a warmer environment.

So the answer to the first part of the question is yes. You do obtain more energy from warm food (compared with food otherwise identical but just served cold) and this extra energy could be effectively used by the body to decrease the metabolic requirements of maintaining body temperature, but the effect would be more noticeable in animals than humans (which is kind of a moot point as most other animals don’t have either a stove or a microwave oven. :p)
 
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  • #26
Other problems with this correlation have been discussed. I'll address this one little place where you do a calculation (and maybe say a wee bit more).

pivoxa15 said:
On food packets, they label the nutritional value of the food, the first one is usually energy. Obviously heated food have more energy than cold food. For example, consider heating a glass of milk (400ml) for a minute in a 1000W microwave oven. A total of 60kJ would have been transferred to the milk after it has been heated. The milk contains a total of 1100kJ before heating, now it contains 1160kJ. That is a small extra amount of energy but still energy which may be valuable in some circumstances. Imaging heating the milk for 10 minutes. That would be 600kJ of extra energy
Wrong. And here's why.

Milk boils at 100.2C.

It has a density of about 1030kg/m3 and a specific heat capacity of 0.93Cal/K-gm. The maximum amount of heat that 400ml of milk can absorb before it begins boiling is :

[tex]\Delta H = \rho V C \Delta T [/tex]

That's about 150kJ. This is less than 15% of the calorific value of milk. And milk has a pretty low nutritional value per unit mass (since it's mostly water). If you were heating a typical meal to 100C, the heat content will remain below 2% of the nutritional value.

http://www.nationaldairycouncil.org/NationalDairyCouncil/Nutrition/Products/table14.pdf

Further, even if this extra heat content were usable (which it is not, in the manner described by you), all the work done in heating the food above body temperature would essentially be lost through thermalization in the esophagus.

A quick calculation for the thermal time constant for a swallowable piece of food gives me a value ranging between a few seconds to a few minutes. In three time constants the piece of food loses over 95% of its heat contant. Seeing as how the digestion process takes several hours, I would confidently hazard a guess that by the time any considerable digestion begins, virtually all the heat content gained by microwaving the food is lost.

**{this part of argument redacted for lack of rigor; but perhaps it might be worth noting that enzyme activity is highly temperature specific - the point of enzyme catalysis being to reduce the activation energy for dissociation down to thermal energies present at body temperature}

As for your analogy with fossil fuels and immense gravitational potentials, that's incorrect too. You can synthesize pretty much every fossil fuel drilled out of the Earth in a chemistry lab that has no capability of generating enormous pressures. Even diamond has been synthesized at way lower temperatures and pressures than those reached by mined diamond. The high pressures and temperatures that facilitate the formation of fossil fuels and things like diamond are only relevant to overcoming an activation energy, and are not related to an enthalpy. There is no conservation law (or Hess' law) however, for activation energies. All the energy used to activate the reactant could be lost in making the product from the activated state.
 
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  • #27
Yes of course there is only a limited amount of thermal energy that you can sensibly add to food without making it too hot for ingestion. Water heats up at approx one degree C for each 4.2 Joules per mL added. But that does not change the fact that this thermal energy can be used by the body in substitution for energy that would otherwise need to be supplied from metabolic processes as outlined in my last reply.
 
  • #28
uart said:
But that does not change the fact that this thermal energy can be used by the body in substitution for energy that would otherwise need to be supplied from metabolic processes as outlined in my last reply.
I agree that heating up to 98F is not wasted in this sense (but doesn't provide the nutrition in the sense that pivoxa describes). Besides, it no longer becomes a question of nutritional value (strictly speaking). For then, as described here, the nutritional value of a food goes up if you eat it in the summertime (just because the ambient temperature is higher, not necessarily even the food temperature). It's just a question of how you do the accounting.
 
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  • #29
Reshma said:
Umm...I have read cooking certain food stuffs like carrots and tomatoes actually increases their vitamin content. :smile:


I think it just increases their absorbtion into the body. Because it doesn't matter what you injest, all that matters is what gets absorbed into your body. For example you take all the calcium you want, but without certain transport mechanisms that can be induced by vitamin D it is difficult to absorb.
 
  • #30
wow, great question. :)
 
  • #31
Reshma said:
Umm...I have read cooking certain food stuffs like carrots and tomatoes actually increases their vitamin content. :smile:

This is most certainly true.
 
  • #32
@pivoxa15

Andrew Mason said:
Not a very scientific approach. Since humans don't work as well when drinking gasoline does that mean that gasoline contains less energy than milk?

Is it that there is more energy in fossil fuel or is it that the energy is more accessible?

AM


Interesting question.

Since fossil fuels are simple Hydrocarbons they are all carbon backbones with Hydrogen atoms attached. For example, the simplest fossil fuel is Methane (C1H4), which is one Carbon surrounded by four Hydrogens. The next simplest is Ethane (C2H6), then Propane (C3H8), Butane, Pentance, Hexane, Heptane, Octance, etc...

To give you more perspective on the word Fossil Fuels, it includes all of these:

- Natural gas (C1-C4)
- Straight-run gasoline (C5-C11)
- Kerosene (C11-C14)
- Gas oil (C14-C25)

With this in mind, to answer your question, live plants have their Hydrocarbon content locked into complex molecules that they use for biological function, so that the hydrocarbons are not found isolated in any part of the plant. For example, a live plant may have compounds in it that have the basic hydrocarbon backbone structure to them, but they are also attached to atoms like Phosphorus, Nitrogen, Oxygen, etc. Whereas, dead plants which have been buried under heavy pressure for millions of years, have two factors that contribute to their liberation of their hydrocarbons; namely Decay, and Heat/Pressure. Both of these factors combined, over sufficient time, help to break the atomic bonds of a plant's hydrocarbon compounds and break off any undesirable residues like the atoms mentioned above, so that a purer, more combustable hydrocarbon emerges.


As a side note, the best fuels have high octane numbers (100 = best, 0 = worst). Octane number is determined prinipally by how 'branced' a hydrocarbon is. For example, Heptane (C7-H16) is a straight line of carbons that looks like this C-C-C-C-C-C-C and has an awful octane number of 0. While, 2,2,4-Tirmethylpentane (C8-H18) has three branches and has a perfect octane number of 100. For this reason, unbranched hydrocarbons are 'catalytically cracked' into smaller pieces and then recombined into larger branched hydrocarbons that are more useful as fuel.

Hope this helps.
 

1. How does hot food provide more energy for the body?

Hot food provides more energy for the body because it increases the metabolic rate. When we eat hot food, our body has to work harder to digest it, resulting in more energy being produced.

2. Is there a specific temperature that qualifies as "hot" for food?

There is no specific temperature that qualifies as "hot" for food. Generally, food that is warm to touch and is above room temperature can be considered hot. However, the temperature at which food is considered hot may vary from person to person.

3. Does the type of food affect its ability to provide energy when hot?

Yes, the type of food does affect its ability to provide energy when hot. Foods that are high in carbohydrates, such as pasta and rice, are known to provide more energy when hot compared to foods that are high in protein, such as meat and fish.

4. Can hot food be beneficial for weight loss?

Yes, hot food can be beneficial for weight loss. As mentioned before, hot food increases the metabolic rate which can aid in burning more calories. Additionally, hot food can also make us feel fuller faster, leading to consuming fewer calories overall.

5. Are there any potential risks of consuming hot food?

There are some potential risks of consuming hot food, such as burning the mouth or throat. It is important to let hot food cool down before consuming it to avoid any burns. Additionally, consuming extremely hot food can also cause damage to the esophagus and stomach lining.

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