09/26/08

IA Word about Calories

This is an area of clearly heightened awareness. The problem is that calories are a VERY vague notion when you consider how they are calculated and what is done with foods in the body. Without going into detail, the calorie content of foods is determined using an instrument known as a bomb calorimeter. In this instrument, a sample of material such as sugar, or protein source is placed in a sealed vessel. The vessel is then pumped up with oxygen gas to a level 30 TIMES the pressure of the air around you. Then, the sample is ignited. Being in an oxygen-rich environment, the sample burns completely and in doing so, gives off heat, as burning substances will do. The heat given off is measured and divided by the weight of the sample to give the calories per gram of food. Now, what is wrong with this as a basis of what we eat?

Summary:

• We are not combustion machines. We do not burn foods in an oxygen-rich environment!

• We do not burn, or metabolize all of the food we eat. Some is indigestible, some is used to build body structures, and some is used to create substances that keep organs functioning.

• All foods have different amounts of stored energy, even among food types such as carbohydrates. The calories per gram of carbohydrate is reported as 4 cal/gram, however differing types vary from 1 to 7 calories per gram! Fats and proteins are worse!

• Your calorie use and need vary day to day and hour to hour based on your unique metabolism, and activity level.

The bottom line is to forget it beyond the obvious over-excesses and under-excesses, each of which lead to their own set of problems. What you will do is to eat, evaluate, and adjust based on your performance and how you feel.