DEAR DR. BLONZ: Please comment about the concept of the cold/ice water diet. It is a means of losing weight that takes advantage of the energy used to bring the cold water up to body temperature. I have seen this described as a passive, but smart, way of burning extra calories. As I recall, a calorie is the amount of heat it takes to raise one gram of water one degree Celsius. So if a person drank 8 ounces (about 227 grams) of cold water at 5 degrees C (41 degrees F), and the natural functions of the body raised the temperature of the water to 37 degrees C (98.6 degrees F), then wouldn’t the body burn 7,264 calories (227 x 32) in the process? Can this be true? -- C.I., Chicago
DEAR C.I.: Boy, wouldn’t that make things simple: the ultimate “chill” diet. Make ice cubes a regular part of your diet and watch stored calories melt away!
It is true that our body seeks to maintain its normal operating temperature of about 98.6 degrees Fahrenheit (37 degrees C). That is the temperature at which most chemical reactions are designed to take place. It’s also true that calories are expended heating up water, or any other cold food. The slap of reality here is that the number of calories burned by bringing cold items up to body temperature is not what you had projected. Your weight-loss hopes fall victim to the thousandfold big “C”/little “c” caloric confusion.
The calorie (note the lowercase “c”) is a unit of energy in the metric system, and it is defined as the amount of heat required to raise one gram of water one degree centigrade. But the calories that are used to describe the energy in foods (or the energy expended by physical activity) are actually kilocalories (kilocals for short), which are the equivalent of 1,000 small “c” calories. One Calorie = 1 kilocalorie = 1,000 calories.
Food/activity calories should have that capital “C” to start the word, but common parlance and usage have blended the two together. In the mind of the average individual, a calorie is a Calorie is a calorie. Even the Nutrition Facts label mixes it up, using the uppercase “C” in some places, but then saying that “Percent Daily Values are based on a 2,500 calorie diet” (which would be the equivalent of 2.5 Calories). No wonder the distinctions get lost. Scientists use the term kilocalorie to avoid confusion with uppercase and lowercase “c.”
Doing revised math with your water-heating exercise, the 8 ounces of water weighs 227 grams, and heating this up 32 degrees would use up approximately 7,264 calories (again, note the small “c”). This is the equivalent of 7.264 (big “C”) Calories, and that is less than a gram of fat. Sorry to take the heat out of your diet plans.
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