system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does drinking cold water not burn a ton of calories?

Science class taught me that a calorie is the energy required to raise the temperature of one gram of water by one degree Celsius. Since energy can’t be created or destroyed, why can’t we get skinny relatively quickly by drinking a bunch of cold water?
gpt
1 pound of fat is roughly 3500 nutritional calories. Each calorie we talk about in nutrition is a kilocalorie, or 1000 actual calories according to the scientific definition you provided. 

Let’s assume you have an 8 oz glass of water at 5 degrees Celsius, which is roughly the temperature of a refrigerator. Your internal body temperature is 37 degrees Celsius, so this is a difference of 32 degrees. An 8 oz glass of water weighs 240 grams. 

Raising one glass of water to body temperature therefore burns about 7680 calories (240 grams * 32 degrees). If you need to burn 3.5 million calories (3,500 kilocalories * 1000 calories/kilocalorie) to burn one pound of fat, you would need to drink 455 cups of water to lose just one pound.

You would probably die of electrolyte imbalance before you made any tangible difference in your weight by drinking water.