# Interesting Question of the Day – 8 February 2017

On Monday we found out that you can’t burn calories just by digesting celery. It doesn’t have “negative calories.”

Ice water, on the other hand, does have negative calories. It has zero calories and your body will burn calories warming it to body temperature.

If you made no other changes to your diet, how many litres of 3 degree ice water would you have to drink to burn enough calories to lose 1kg of fat?

The first new player to comment within 20 litres of the correct answer wins a free drink at their next iQ Trivia show.

1kg of fat = 7700 calories

Heating water is 1 calorie per degree Celsius per gram (or mL)

Average body temp = 37 degrees Celsius

34 degree increase required to raise water to body temperature

7700 / 34 = 226.4706 mL

The math is bang on, except for the starting point.

When people talk about 7,700 calories, it’s actually 7,700 kilocalories, which is 7,700,000 calories.

Which makes the answer 226 litres.

If you lost a kilo of fat every time you had a small cold drink, you’d waste away pretty quick.

948 litres, but that completely depends on how efficiently body fat would be converted to heat.

Ooops – mixed up the units. 226 litres, assuming that 1 kg of body fat contributes 7700 kcal of heat when burned.

There you have it.

Fat is 9 calories per gram so we need to burn 9000 calories.

A calorie raises the temperature of 1 litre of water by one degree.

Body temp is 36 degrees so we need 33 calories to heat each litre.

So we have to drink 9000 / 33 = 273 litres of water.

The starting point is a little bit off from what I can tell, but otherwise that’s it.

At any rate, it is not a viable fat loss strategy. You would burn more calories walking to and from the toilet with all the peeing you’d be doing.

Also, your kidneys would be overworked and you would wind up with hyponatremia.

So don’t try to drink hundreds of litres of water.