Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: thedoc on 10/08/2016 13:23:01

Title: Does the temperature of your food affect the energy it gives you?
Post by: thedoc on 10/08/2016 13:23:01
Olivia asked the Naked Scientists:
   Does eating food which is cooled/heated up provide you with less/more calories? --> could eating ice burn calories? Or would it melt inside due to energy which is a byproduct of the processes going on inside, rather than the body regulating the temperature of your food.
What do you think?
Title: Re: Does the temperature of your food affect the energy it gives you?
Post by: alancalverd on 10/08/2016 13:53:53
You need to remember that a nutritionist's Calorie is 1000 "physics" calories. 100gram of chocolate will give you 577000 calories of chemical energy. 100 gram of chocolate heated from 20 to 100 deg C acquires about 6000 calories of heat energy, so although a hot chocolate drink (at, say, 40 deg C) gives you a pleasantly warm sensation in your mouth, it won't keep you alive much longer than just eating the chocolate cold. Indeed by stimulating facial blood flow, it may even hasten your demise in an emergency!

The key to survival in UK latitudes is always 1: shelter (get out of the wind & rain so you don't lose body heat) 2: eat  3: plan your rescue or extrication 4: if in doubt, rest and eat rather than panic.  A surprising number of bodies are recovered intact, dead from hypothermia, and carrying uneaten food.

Eating ice, on the other hand, may cause frostbite by shutting down facial circulation - most unpleasant. You will inevitably lose some heat through your clothing so a bag of snow under your outermost layer will probably melt into something potable without causing acute damage. 
Title: Re: Does the temperature of your food affect the energy it gives you?
Post by: Villi on 14/08/2016 06:26:07
The body incorporates nutrients into itself and keeps them at 37 degrees Celsius. I think that if you eat something cold, the body would have to heat it up first, spending energy and metabolizing a few things to put that heat into the cold thing, which burns calories/joules. The body needs to maintain homeostasis. Alternatively, things over 37 degrees would give you heat and more calories.