heat & appetite

[Ginger Rogers]

Why is it that when it's hot I don't seem to get hungry and don't have much appetite?

[Mongrel]

Off the top of my head it's because your body doesn't need as many calories to maintain it's normal temperature.

[Admin]

I've noticed this. I had put it down to feeling fuller because of drinking more fluids.

[median]

Indeed, it may be that "the important factor in regulation of food intake is not its energy value, but rather the amount of extra heat released in its assimilation" (Strominger and Brobeck, 1953). Thus, this "thermostatic hypothesis" of feeding argues that the total energy content of the food is not the determining factor in regulation. Energy that becomes stored as fat does not control feeding; rather, it is the direct heating effect of food intake that is monitored and that provides a regulatory mechanism.

According to this view, if the environment is cold, the resultant heat loss demands compensatory strategies, including notably increased food intake for its thermic effect. By extension, if the ambient temperature is warm, and heat loss is not an issue, there ought to be a reduced caloric demand. And should the environment become significantly hot—which changes the concern from how to obtain energy to how to dissipate it—a suppression of caloric intake should be expected. "At a high temperature where loss of heat is difficult, food intake should be low, lest by eating and assimilating food the body acquire more heat than it can dispose of" (Brobeck, 1948). This temperature-dependent variation in energy needs should, in principle, be reflected in appetite. Brobeck (1948) claims that "everyone knows ... that appetite fails in hot weather."



From http://darwin.nap.edu/books/0309048400/html/189.html O0

[Admin]

Actually, the military's ration packs for soldiers operating in arctic conditions have a higher calorie content for this very reason.

I don't know what the difference is, but it does make sense that we'd have to burn more calories to maintain body temperature in cold conditions and vice versa.

[Ginger Rogers]

so how does what you eat maintain your body temperature then? (I do apologise if that's a very thick question lol)

[Mongrel]

so how does what you eat maintain your body temperature then? (I do apologise if that's a very thick question lol)


Simplified version: Calories are a measure of energy - 1 calorie is the amount of heat needed to raise the temperature of a gram of water 1C. When you eat your body breaks down the food and is able to convert it to energy and some heat, some things are converted easier than others depending on how complicated they are. Any excess is then converted again to fat for storage. From Meridians article, if I've understood it correctly, some foods produce a lot more heat than others when broken down and will raise your body temperature almost immeadiately.

The traditional analogy is a furnace: You throw fuel (food) in a furnace to keep the heat up and produce some excess which is then converted to electrical power for battery storage. Some fuels are more volatile than others (think petrol an a BBQ) and the furnace burns hotter briefly with no way to store it, thus the extra heat is vented and raises the ambient temperature above the required limit.

[median]

Calories are a measure of energy - 1 calorie is the amount of heat needed to raise the temperature of a gram of water 1C

;D Hey lets go S.I.

Out with the Calories/calories and in with the Joules ;D ;D

Mmm I seem to be willing to adopt certain measures but still measure weight and height, old style :o :o

[Mongrel]

;D Hey lets go S.I.

Out with the Calories/calories and in with the Joules ;D ;D


Meh - it's not something that bothers me too much in everday life, if I'm restricting calories then a number scale is a number scale. On the other hand for explainations I find the definition for calorie requires less explaination than the Joule



1. The International System unit of electrical, mechanical, and thermal energy.
2.
1. A unit of electrical energy equal to the work done when a current of one ampere is passed through a resistance of one ohm for one second.
2. A unit of energy equal to the work done when a force of one newton acts through a distance of one meter. See table at measurement.
(from Dictionary.com (http://dictionary.reference.com/browse/joule))

People can visualise water being heated quite easily whereas, for Joules, a lot of people will be asking "WTF's a newton?"


Mmm I seem to be willing to adopt certain measures but still measure weight and height, old style :o :o
I think that's true for a lot of people. I know that Metres and Kilos are a much more logical system, it's what I got taught in school - but when I went into the world of buying for myself - everything was in pounds\Ozs and Miles, Yards and Acres. Now that we're finally, properly, moving that way I still get confused :( Still, I have adapted to Litres better than any of the others as the Imperial liquid measurement is probably the most confusing out of them (I mean who thought Gill was a good name for a measurement :o)

[Aardvark]

Landlord, kindly produce for me a quart of your finest ale!! :P O0

[Lord Muck oGentry]

My thumbs have gone weird.

[Mongrel]

Landlord, kindly produce for me a quart of your finest ale!! :P O0


Nah - the Germans have it right, by the Litre : :booze: