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Does being cold help lose weight?

I read this comment on a YouTube video showing body builders having breakfast:

Ice water. That's the key. Not just plain water - you gotta put ice in it. Otherwise your gains in the gym just go kaput. It's the secret of the pros. Especially during contest prep. Burns an extra 1000 cals a day of pure fat.

Obviously YouTube comments by random people who most of the time are just spewing nonsense is not to be trusted but this one really caught my attention because of the ramifications if it's true. So I rather ask the experts, is there any truth to this and if so why?


NO. A calorie is defined as the amount of energy needed to warm 1 gram of water by 1 degree C. Lets imagine an extreme implementation of this advice - someone who eats a gallon of ice slush per day. That's about 4000 grams or 4 liters. If the H2O goes from freezing temp (0) to body temp (37), the energy consumed is 14800 calories. Since one metabolic "calorie" is actually a kilocalorie in physics terms, the amount (148 calories) is negligible, hardly close to the 1000 calories claimed. More like a couple eggs or apples.

  • While the math may be accurate, you seem to be assumin our bodies can use 100% of the provided calories and get 100% efficiency using them? Im not arguing that eating ice is good or helps, but math such as Yours suggest that eating and apple should be enough to climb mount everest – K.L. Oct 15 '12 at 12:27
  • K.L., I don't follow your logic. Climbing Everest from basecamp to peak is 12,000 vertical feet, which even at sea level without harsh conditions would expend thousands of (kilo)calories. In mountain climbing conditions, we are talking about many days of intense activity. An apple containing usable energy of ~80 kcal is not even close. – J. Win. Oct 17 '12 at 23:02
  • But it the same logic you applied! You said 1 kcal is the amount of energy to warm up 1kg of water by 1 C. And I say 1 kJ is equal to the energy expended in applying a force of one newton through a distance of 100m(1000 newton metre or N·m). An apple has around 200kJ thats moving 1kg by 20 km! Looks like enough to move a human quite far, isnt it?! Our bodies are not 100% energy efficient. And thats why moving OR warming our bodies takes more energy than the naiive interpretation of equations would tell us. Earlier my numbers werent accurate, they were supposed to prove a point. Hope they did. – K.L. Oct 18 '12 at 6:28

Cold food would affect the homeostasis of your body, requiring more heat to be produced to bring it back to 37 degrees, so there's probably some truth to it, but not to the extent suggested.

A much more likely reason that bodybuilders drink so much water for contest prep is cutting weight. If you drink a ton of water and then stop 12-24 hours before the contest, you'll cut anywhere from 10-30lbs by pissing it out and sitting in a sauna in a sweat suit. I've cut 8% of my bodyweight in water doing that. Ice water might factor in there as well, as people in hot countries drink spicy tea to deal with the outward heat, whereas drinking ice water or slushies leaves you still sweating just as much.

Cutting water weight leads to much better muscle definition, so it's quite understandable that someone might confuse 30lbs of water weight with 1000 calories worth of fat.