Quote:
Originally Posted by JayEll
Oh, drinking cold water does burn some calories because it gets heated up inside the body. But, the values in the article are estimated and calculated--that is, no one actually measured how many calories are burned by drinking 8 glasses of ice water in a day. It may depend on lots of individual factors--how big the person is, how fast they drink the water, what the temperature of the room is...
In a college human biology course (in 1985), our professor lectured on this, and negative calorie foods. If you adjust for the temperature's affect on metabolism, there are absolutely no zero calorie foods (even celery) and a pitcher of ice water (I don't remember if he used a 1 quart or 2 quart pitcher) has a whopping maximum impact of about one negative calorie.
The article's math is wrong, because it doesn't calculate in the effects of the ice water on the body's metabolism. It assumes that metabolism will stay constant during this process - and also assumes that the person's body temperature is remaining constant.
If one would use this flawed math, hot (temperature) foods and beverages would always have more calories than cold - BUT that's a bit like saying you will use less energy/electricity in the summer by using your air conditioner. Electric bills tell a different story. We use energy (burn calories) to cool our bodies as well.
The temperature inside our bodies and the temperature outside our bodies play a role here. If the external temperature is so hot that our bodies are working hard to keep us cool, ice water can make the job easier (would perhaps would result in burning fewer calories). Likewise, if the external temperature is cold enough that are bodies have to work to keep us warm, hot beverages would assist that (and might result in burning fewer calories). But even that is assuming that the "furnace" is not affected by the fuel that is being used (which is not the case).
Changing the temperature in the body can affect metabolism (the rate at which we burn fuel), and drinking cold beverages can lower body temperature. Some people have more efficient systems than others at maintaining a consistent body temperature, so this is going to affect different people to different degrees. It takes fewer calories to maintain a lower body temperature (fewer calories to heat and fewer calories to cool), and the temperature of foods/beverages can affect body temperature (at least temporarily).
There are also other processes in the body (all of which burn calories) that can be altered by our intake (both the quality and the quantity of the fuel), so some foods or beverages (or temperatures of each) can affect how many calories are burned by the cumulative effects of all those processes.