Wikipedia:Reference desk/Archives/Science/2019 November 22

= November 22 =

Fat burning
If a person is predominantly burning fat in his/her body, rather than carbs, due to a low carb diet, does he/she smell any different from other people who are predominantly eating more carbs? If so, how does it smell. Is it pleasant or unpleasant.? 86.8.200.208 (talk) 01:41, 22 November 2019 (UTC)
 * Define "pleasant" and "unpleasant". -- Baseball Bugs 01:47, 22 November 2019‎ (UTC)

Is it 'deemed' pleasant or not by the general mass of people, during the normal working or relaxing day/evening in the bar or at home or on the train etc,who are smelling it? 86.8.200.208 (talk) 02:13, 22 November 2019 (UTC) Ok. If you want to be awkward, just what does it smell like?

You are probably thinking of the smell associated with the ketogenic diet. Our article doesn't seem to say anything about it, but you could try a web search with those search terms. 173.228.123.207 (talk) 04:05, 22 November 2019 (UTC)


 * I am aware of "keto breath" (see https://www.healthline.com/health/keto-breath and https://www.webmd.com/oral-health/features/low-carb-diets-can-cause-bad-breath ). I did a google search on [ ketone body odor ] and found a lot of sites talking about it, but I didn't see any reliable sources. I would like to see a WP:MEDRS source that talks about it, and especially whether it is temporary until you adapt to the diet. --Guy Macon (talk) 17:08, 22 November 2019 (UTC)

What the mechanism by which vinegar has a cooling effect while eating it?
"The effect of vinegar was astringent, but it was also used frequently because of its soothing and cooling effects". It states that Ruth was bidden to dip her bread into vinegar (Ruth ii. 14). See here. Is it scientific true that vinegar can cool a body by eating it? What the mechanism by which vinegar has a cooling effect while eating it? ThePupil (talk) 02:56, 22 November 2019 (UTC)
 * Your source doesn't specify that the cooling effect is from consuming it. More likely, it is applied topically. The source also mentions that "it might be employed for dandruff, and even for dressing wounds".  2606:A000:1126:28D:144E:A9EA:EDD2:AB72 (talk) 06:37, 22 November 2019 (UTC)
 * I left below the sources that I forgot to added. You'll find there what I stated. ThePupil (talk) 20:52, 22 November 2019 (UTC)
 * Also for treating sunburn. ←Baseball Bugs What's up, Doc? carrots→ 07:01, 22 November 2019 (UTC)
 * Surely vinegar mentioned here not as a cooling food, but, still, it is still mainly water, and as such WILL cool by ingesting. The energy of acetic acid can be used inside the body, releasing 875 kJ mol−1 / 14,58 kJ g−1, but this is too low to offset the cooling effect of water. So, it IS scientific truth that vinegar can cool a body by eating it, the mechanism by which vinegar has a cooling effect while eating it is just the same as water's. Gem fr (talk) 08:22, 22 November 2019 (UTC)
 * Does it mean that the they have the same level of effect? If so, why did they use vinegar for this purpose, while water is cheaper and tastier?ThePupil (talk) 20:52, 22 November 2019 (UTC)
 * Water (and food!) was a killer at the time (and remained so, well, pretty much until 20th century, AFAIK), unless you are very sure of its purity, or disinfect it in some way. Physical mean like boiling it would do. Chemical mean such like adding vinegar also would, and could be more practical and cheaper, especially when you don't want heat; it seems that this was pretty common in the space-time you are interested in. Gem fr (talk) 22:58, 22 November 2019 (UTC)
 * Water always was a source of infections, and it's still. But it didn't avoid people to consume water ever. So the explanation you suggested doesn't make sense not only because the bible is full of descriptions of people who drunk water as an habit, but mainly because a few verses above in the same chapter (which describes that they dipped the bread in the vinegar (not drunk it!) there is a verse which mentions that they drunk of that which they have pumped (from the well, i.e. water). ThePupil (talk) 00:02, 23 November 2019 (UTC)
 * It could also be perceptive effects. After all, mint doesn't lower the temperature of your mouth, but it activates sensors in your mouth to make you perceive a sensation of coolness.  That may be what they are talking about.  -- Jayron 32 13:13, 22 November 2019 (UTC)
 * The energy of acetic acid can be used inside the body, releasing 875 kJ mol−1 / 14,58 kJ g−1, but this is too low to offset the cooling effect of water (emphasis added) citation or calculation please, because I strongly suspect that affirmation is somewhere between "wrong" and "not even wrong". Tigraan Click here to contact me 14:55, 22 November 2019 (UTC)
 * water cools you mainly through evaporation, taking away (more or less; not exact because starting temperature, different pressure, etc.)2257 kJ/kg of evaporated water, so you need to turn ~155g of acetic acid entirely into heat to offset that. Common vinegar would have, like, 3x or more less acetic acid, AFAIK, so, too low to offset the cooling effect of water. Gem fr (talk) 17:47, 22 November 2019 (UTC)
 * You are simultaneously addressing energy released from ingestion and energy used for evaporation. Ingested substances do not seem likely to under go evaporation. DMacks (talk) 18:01, 22 November 2019 (UTC)
 * ingested water IS likely to undergo evaporation when cooling is needed (less so when cooling is not required, of course). Now, if you claim that ingested water won't cool you, well, you crossed my limit. Gem fr (talk) 18:25, 22 November 2019 (UTC)
 * OK, not even wrong then. The calculation (enthalpy of combustion of acetic acid) - (latent heat of water) may well yield a negative number, but drinking an amount X of water will not increase body evaporative cooling proportionally to X (see Homeostasis, Thermoregulation, etc.).
 * I was thinking of the calculation (enthalpy of combustion of acetic acid) - (heat capacity of water × temperature difference between ingested water and body) which yields almost surely a positive number (which makes the argument "wrong"); it probably is not too wrong for the heat capacity part, but physiology considerations would still apply to the combustion part (ingested organic matter is not entirely released as a mix of CO2, H2O and nitrates, so you cannot assume the combustion is close to complete). Tigraan Click here to contact me 13:24, 25 November 2019 (UTC)
 * Oh dear. congratulation, you just proved that you cannot rely on drinking water (or, even worse, hot sweetened tea) to cool you. That, or you missed the point. Your choice. Gem fr (talk) 14:02, 25 November 2019 (UTC)


 * The article about vinegar which I cited earlier also points out that cool water also helps relieve the sting of sunburn. So it might indeed be the water in vinegar which is doing the job, equal to or more so than the pungent parts. ←Baseball Bugs What's up, Doc? carrots→ 18:40, 22 November 2019 (UTC)
 * Here is a group of interpretators of the bible that say: vinegar consumption has a cooling and refreshing effect. I'd like to ascertain it scientifically. ThePupil (talk) 20:46, 22 November 2019 (UTC)
 * Original Research, but I have personally observed that adding a small quantity of vinegar to tap water (which by law is of potable quality in my country) makes the water more palatable and "refreshing", masks any harmless but unappealing tastes resulting from water treatment, etc., and therefore encourages one to drink more of it.
 * In a Biblical context, I would observe that the alcohol in wine (and other alcoholic beverages like beer) exposed to the air turns partially to vinegar (the word literally means "sour wine") which was likely how most vinegar was anciently manufactured, and partly soured wine has been claimed to have been called vinegar, and commonly drunk, by Roman soldiers. {The poster formerly known as 87.81.230.195} 2.217.209.178 (talk) 13:24, 23 November 2019 (UTC)
 * I don't like the smell of vinegar (and so dislike most things with enough vinegar that you can smell/taste it e.g. vinegar chips). So adding it to water is unlikely to make me drink more water. I've never had a problem drinking most tap water, even in Malaysia where it can sometimes be quite chlorinated although the norm there is to boil water and so there is a standing period which reduces it somewhat. OTOH, I do find even during winter I actually prefer ~4 degrees C water from the fridge compared to 10-20 degrees water from the tap and it probably makes me drink more. Nil Einne (talk) 15:53, 23 November 2019 (UTC)
 * The amount of vinegar I employ is a few drops in, say, 1/3 of a pint of water, nowhere near enough to smell, or to actually taste of vinegar. {The poster formerly known as 87.81.230.195} 2.217.209.178 (talk) 22:03, 23 November 2019 (UTC)
 * Thank you all for the participation and sharing your interesting opinions in this discussion. ThePupil (talk) 05:52, 25 November 2019 (UTC)