[leereeves]

And a pound of fat contains 3500 Calories (kcal), so drinking about 100L of ice water would consume one pound of fat.

One could drink 15L per day (about one liter per hour and 5x the recommended minimum intake) and burn about one pound of fat per week.

[brador]

Or just sit in an ice bath. Also, I wonder if the reverse is true: if you drink a warm drink does that cause calories that would have been burned heating you to not be burned?