Drinking ice water really does burn calories

We've all heard that line, but to me, at least, it always seemed like the scale must be so small it couldn't possibly be perceptible. Then I was reading a description of the phenomenon today that said if you drank all your water ice-cold, it could be equivalent to adding a workout a week.


So I got interested, and calculated it.


It's actually fairly easy to calculate. The specific heat of water is 1 calorie per gram per degree Celsius (little calorie, not food kcal), and its density is 1 gram per milliliter. (A lot of things are defined in reference to water.) If you drink ice-cold water, it is at 0 degrees Celsius, and the temperature your water is probably usually at is around 20 degrees Celsius.


What this means is that to warm up water from 0 degrees Celsius to 20 degrees, you have to put in 20 little calories for every milliliter of water you have. When it goes into your body, it actually has to warm up further to around 37 degrees, but your body is already doing that when you drink room temp water, although that also means if you just drink more room temperature water in a day it will burn more calories too. Anyway, if you drink 2 liters of iced water a day, that's 2000 x 20 little calories = 40,000 little calories = 40 kcals, or food calories. 40 calories a day! In a week, that's 280 calories - a light workout, an extra pound every 3 months or so. Not so negligible.


What's neat about this too is that this is non-negotiable calorie burn. It's just heat transfer. It's not something your body can do more efficiently, or kind of do a crap job on to save energy. By the laws of thermodynamics the water will suck heat out of your body, and your body can either compensate or tolerate hypothermia. Granted, anorexics who try to practice this trick probably will reap more hypothermia than calorie burn from it, but for the rest of us, I doubt our bodies are desperate enough to refuse to heat up ice water. Cheers!

My dad's diet

My dad is such a dork. He has no milk in his fridge, only half-and-half. He puts it in his coffee and also on his cereal, which he doesn't eat in the morning, but rather at night if he gets hungry after dinner. One of his favorite ridiculous snacks is Fruity Pebbles with half-and-half.

He also revealed that his usual eating routine involves no breakfast, a constant supply of coffee all morning, then for lunch fast food, or more recently turkey and vegetable wraps that he brings from home, or on a bad day, a string of chocolate bars until the end of the workday, and finally a huge dinner. I know from experience typical dinner is pasta or frozen pizza, although I think he eats meaty, higher-protein options without me. And admittedly, there are more vegetables in his fridge now than I am accustomed to seeing.

Incidentally, he's pretty in-shape. He runs fairly long distances (5 miles easily, marathons on special occasions) He's 5'11" and has usually been between about 165-195, and he's looking like he's on the fit side right now. I don't really know how this works.

When we go into town later, I will buy myself a quart of skim or 2% and maybe some apples or lettuce. He has juice and chopped-up peppers and onions and celery, but I don't think I saw any whole fruits and I'd have to go check again to see if there's any salad greens. There was dressing, but that doesn't mean he uses it often. It might even be for the wraps.