Intermediary metabolism is another difficult term that helps us understand how low-carbing works. Let's break it down:
inter - between
mediary - acting
bolism - placing
The idea is that we have a process acting between one thing and another, transforming or changing the thing from one form to another form.
Intermediary metabolism describes the hundreds of biochemical reactions that take place in our bodies every second. Through intermediary metabolism, the food we eat is transformed into energy. Through intermediary metabolism, our food is also transformed into new molecules that are then used to make up cellular organelles, cells, and tissues. Although all of the biochemical reactions are now understood in great detail, we can think of intermediary metabolism as the black box that takes the nutrients we eat and transforms them into the structures of our bodies and the energy we need to run them.
For those who would like a simplified overview of the process of intermediary metabolism, here is an illustration found in the Elmhurst College Virtual Chembook by Charles E. Ophardt.
People like to say, "You are what you eat." That sounds right, doesn't it? But if it were true, the prototypical policeman would resemble a Krispy Creme. The vegetarian would look like a stalk of broccoli. Why don't they? Because of intermediary metabolism. Within certain limits, our bodies are able to take in what we eat, break it down into pieces of molecules, and build it back up into the molecules we need to build and to run our bodies. In other words, intermediary metabolism is what makes us what we are in the physical sense.
Because of intermediary metabolism, the fat we eat does not have to become fat in our bodies. It can be burned as fuel. Because of intermediary metabolism, the cholesterol we eat does not have to become cholesterol deposits. It can be incorporated into cell walls to make them less rigid. Because of intermediary metabolism, the carbohydrates we eat can easily be transformed into energy or, if conditions are right, turned into fat, stored, and locked into storage.
Bottom line: You are NOT what you eat.