This is a common problem during wild camping or survival activity, especially during colder seasons. You are tired, you have lost a lot of calories during day, and now you want to wash, but the only option you have is the cold water in the stream. And the temperature outside is also not very warm.
So, you want to be clean, but you don't want to lose another big portion of calories because of that, because your body is already driving on reserves.
But how much calories are lost when you, let's say, spend a 5 minutes naked and wet, with about 1 minute inside cold water (or pouring cold water on yourself, like in cold shower)? Of course, the exact answer depends on many factors, such as body mass, the fat/muscle factor, the exact temperature, etc., but I need only estimates, such as about 100 calories (which can vary from 50 to 200). Would it be about 100 calories, or 250, or 50?