We must first understand that thermochemical calories are used in physics while nutritional calories are used with food and metabolism. A thermochemical calorie is the amount of energy it takes to increase 1 gram of water by 1 degree Celsius. A calorie calorie known to most people is 1,000 times a thermochemical calorie. (A nutritional calorie is defined as the amount of energy required to increase 1 kilogram of water by 1 degree Celsius.) In scientific textbooks and magazines, nutritional calories are referred to as kilocalories (kcal) to avoid confusion. In your online experience, equating these two has led to incorrect conclusions.
For example, let’s start with 8 ounces (227 grams) of refrigerator-temperature water at 41 ° F or 5 ° C. Once consumed, the body energy brings this water to a body temperature of 98.6 ° F (37 ° C) – an increase of 32 ° C degrees Celsius (37 – 5 = 32). Multiplying 227 grams x 32 degrees gives 7,263 thermochemical calories. We must now express this as nutritional calories, which involves dividing by 1,000; This translates into about 7.3 nutrient calories to heat the 8 ounces of cold water. Assuming 3,500 calories in a pound of body fat, it would take about 30 gallons of cold water to use up the calorie equivalent of a pound of body fat.
Cold showers don’t do much either. In a cold shower, the body directs the blood away from the surface of the skin to avoid unnecessary heat loss. As with cold water, there is also a certain loss of calories here, but this is not enough to make a significant contribution to the loss of body fat.