Ice cold food & drinks and its effect on metabolism. If any.

October 26, 2014 3:23 AM

Just wondering: Thinking about increasing waist-lines and the late 20th century penchant for iced drinks. If a load of ice cold liquid hits your stomach and lowers your core body temperature, presumably your metabolism has to compensate in some way. Is there any evidence of any long term impact to metabolism?
posted by marvin to Health & Fitness (7 answers total)

I can't speak to the science, but I have struggled with disordered eating a lot, more when I was younger than now, and especially back then--well, it may have changed since, but received wisdom in my younger years was that you should try to consume as much ice water as possible because your body was going to burn more calories to raise your body temperature. I have no idea if it really worked, but if it had led to any measurable quantity of weight gain over drinking room-temperature water, I'm pretty sure I would have noticed.

The one place I could find was Fox, so take with a grain of salt, but there are suggestions that the body might burn more fat at lower temperatures, keeping you warm. Or something.

Either way, I'm pretty sure that the sugar content of said beverages makes a lot more difference. There might also be something to the idea that hot beverages slow you down--you can't gulp down 12oz of hot coffee in sixty seconds. But seeing as I lived on ice water and unsweetened iced tea at that point and didn't start gaining weight back until I switched back to sweetened beverages (well, and eating, let's be honest) this doesn't seem plausible to me.
posted by Sequence at 3:57 AM on October 26, 2014

You do burn calories warming up ice-cold liquids, but it's a fairly small amount.
posted by O9scar at 5:05 AM on October 26, 2014 [4 favorites]

The straightforward thermodynamics here should suggest that the effect is going to be relatively minimal. The definition of a Calorie is the amount of energy required to heat a kilogram of water one degree Celsius. So if you shotgun a half-liter bottle of water (weighing half a kilo) straight out of the fridge (~5 degrees Celsius) and you have to bring that liquid up to your body temperature (~37 degrees) the energy required to do that is ((37-5)/2) = 16 Calories. For comparison, you might burn a similar amount in a minute and a half of vigorous exercise.

Of course the simple thermodynamics don't necessarily tell the whole story. Our bodies are constantly generating heat as a byproduct of metabolism, and generally the body is more concerned with keeping our temperature down by getting rid of that waste heat, than generating enough heat to keep warm. If your body responds to all that cold liquid by reducing your heat loss (for example, by constricting the blood vessels near the skin to reduce heat exchange with the air, or even just making you think "I'm cold, I'll put on a sweater), you're not actually affecting your energy budget even as much as that 16 Calories number would suggest.
posted by firechicago at 5:16 AM on October 26, 2014 [2 favorites]

On the flip side, you have to add much more sugar to something to have it taste sweet when it's cold. Ever had some melted ice-cream or a room temperature Mountain Dew?
posted by Metafilter Username at 8:26 AM on October 26, 2014 [3 favorites]

Best answer: Quoted all over, but no actual source:
German researchers found that drinking 6 cups of cold water a day (that's 48 ounces) can raise resting metabolism by about 50 calories daily
posted by Ideefixe at 9:10 AM on October 26, 2014

When the body has to do more temperature regulation, that actually burns slightly more calories, so icy cold water would be helpful, in a miniscule kind of way. Related but not what you were asking, air conditioning takes over from our natural metabolic temperature regulation, such that HVAC contributes to obesity.
posted by aimedwander at 10:31 AM on October 27, 2014

Best answer: Since people are repeating the technical fact but not the important aspect: drinking ice water is the dietary equivalent of having one less grape per day.

Also, note that ice melting energies are listed in heat calories; food calories are actually 1,000 heat calories. So, it's easy to massively overestimate how much benefit there.

TL/DR: Ice has NO SIGNIFICANT EFFECT on your metabolism.
posted by IAmBroom at 2:07 PM on October 27, 2014