V. WHAT IS SO HOT ABOUT A CALORIE?
It is energy. It makes things happen. So what is happening?
You know that too many calories are bad for you. Our canned and packaged foods must display their calorie content. That is a form of warning. There is no doubt that calories do count! So what is a calorie and what does it do?
The derivative of the word is “heat.” In Latin and its derivatives, calor is the hot water
faucet. Since the word “calorie” is everywhere, maybe we should know where it comes from.
Active investigations started in the nineteenth century. Scientists have always been curious about energy. You need energy to keep warm or get cool. Energy runs our automobiles, trains, and airplanes. You know that there is enormous energy in every atom. Einstein taught us that energy is a product of atomic mass and light. Only a genius might conclude that light is energy, but thinking about it as such helps explain why light can hurt our eyes, and don’t you love the warmth you get from the sun’s waves.
Where do you get the energy to function? The source is food.
Scientists began to attack this problem in the mid-nineteenth century. Body heat is a good place to start because somehow we maintain heat, our body temperature, under cold conditions. In order to create heat or a fire, you need oxygen. Oxygen mixes with wood (carbon) to create a fire. However, you do not want a fire because your cells will not stand for it. You have a regulatory system that keeps you in a comfort state or balance. Physicians call this “homeostasis.”
The experiments began by translating the basic knowledge of combustion—e.g., carbon and
carbon dioxide from the air and can turn it into oxygen alone. Aha, oxygen and carbon and fire. Hooray for green plants, your best friend for making use of carbon and oxygen. Wilbur Olin Atwater did the best early research at Wesleyan University in Middletown, Connecticut. An experimental subject was put into a sealed small room, and lived there with the comforts of a bed, chair, telephone, toilet, and stationary bicycle. The walls were insulated. The outside air temperature was kept out and inside a lamp, burned alcohol so the amount of alcohol used became the standard to compare with the events. Within the walls were copper wires to measure temperature, the thermometer. Tubes with cool water circulated in and out of the room. If the water was warmer, coming out than going in, that meant the heat had to be generated in the room. When the room temperature rose, it was because of the heat generated by the person. There are other details, but these points should help you get the picture. Atwater used this model to measure change in temperature from different activities. Generation of heat will raise the water and air temperature, a double-check system. Now the subject can eat different foods and see what effect they have on temperature. Let us create a unit of measurement because we have three variables to consider, namely heat, water, and temperature. Let us call a calorie the amount of heat generated to raise the temperature of water one degree. (Unfortunately, a calorie is so small that the numbers become awkward for communication so you multiply by a thousand to make it a kilocalorie, a kilogram, and one degree Celsius, in the metric system). Your temperatures does not rise that much after you have eaten, so basic experiments had to be done with dried food in a closed jar with oxygen. The information obtained has been refined, but the original data was generally accurate. Eating fat creates the most heat. Carbohydrate and protein make half as much heat. Carbohydrates contain bad sugars, but those in green vegetables have precious fiber, carbon, and oxygen. Fruits have fiber and vitamins, but vary in sugar content.
Proteins are part of meat, chicken, fish, nuts, eggs, legumes and other dairy products. Animal fat is not good, but certain oils are important, particularly olive oil. It may protect our heart and blood vessels. Taking in carbohydrates gives a large source of energy, so you had better burn it off. If not, it turns to fat, not muscle.
Understanding the body’s caloric reactions to food can guide you to better eating and
Figure 5. Food digestion: Calories eaten minus amount used for digestion.
Note the effects of foods on caloric production and appearance of the individual. Igniting
carbohydrates give a net caloric change of 4.1 per gram of food; protein, 5.7 and fat have
approximately 9.3 per gram. Our bodies change the equation because you need energy to digest
the food. Digestion of protein burns the most calories—around twenty-five to forty out of one hundred calories consumed, but carbohydrates only from six to eight out of one hundred calories,
and lastly fat, three out of one hundred calories. So if you do not want your body to work, eat fat
Under normal conditions, cells use glucose as its primary energy source. When it enters
the cell, it undergoes a series of steps that change it into a form that the cell’s energy making
machines (mitochondria) can use. A drug 2-deoxy- D-glucose can block the metabolism of
glucose in the cell. This means the entry of fewer calories, and the scientists call this a glucose-
mimicking drug. This blockage leads to lower blood sugar and better insulin sensitivity, the
reverse of what happens in obesity. In animals, it results in weight loss and health benefits. (See
Scientific American, August 2002, “The Anti-Aging Pill,” by Lane M.A., Ingram D.K. and Roth G.S.). This offers a possible new drug approach to obesity.
Answer: Understanding the basics shows how calories do count, but different foods place
burdens on the body. Glucose is your demon, and we must adapt by creating strategies to
reduce its poisonous action. Knowing about these burdens and manipulating your food
intake can help you not to gain weight. Calories are an enemy that you must get under
control. What is truly hot is to avoid hunger and tame the calories.