Sunday, December 19, 2010

All Calories Are Not Equal

Counting Calories has been a basic tenet of weight loss for many decades. It is simple bookkeeping and usually works fairly well. However, recently there has been debate whether there is an ideal macronutrient (fat/carb/protein) ratio. While the compositions of diets can vary tremendously, and individual biologies do too, the Caloric measurement, itself, may be somewhat inaccurate. Let me clarify that. The Caloric measurement is very accurate outside the body (in a closed, laboratory calorimeter). However, inside our bodies not all Calories are equal.
There are three reasons why:

1. Thermodynamics- I am sure this is not the most fascinating topic for you, in fact, some of your eyes are starting to glaze over just at the sight of that dreaded chemistry term. But, I will explain in plain English. You are not a calorimeter; the energy exchange in the body is not 100% efficient. In fact, biochemistry is driven by a decrease in energy states. All you need to know is a Calorie outside the body does not always provide the same amount when metabolized inside the body.

2. Hormonal Regulation of Energy Use- The glycemic load (how much blood sugar rises) and insulin levels are most closely related body fat stores (or gain or loss). Foods that contain sugar and processed carbohydrates (and little fiber) enter the blood rapidly raise insulin levels. Insulin serves as the main regulatory hormone that signals the uptake and storage of glucose, often increasing bodyfat stores more than would be anticipated by excess Calories alone. Diabetics who start insulin therapy are a good example.

3. Metabolic Pathway Efficiency- A regular supply of glucose is vital. Carbohydrates (various types) are very efficiently converted to molecules of glucose. Although, amino acids can be converted to glucose, but at a higher energy cost. Amino acids are not as efficiently converted to glucose. Thus, 4 Calories of carbohydrates may not be equal to 4 Calories of protein.

So what does this all mean? It means that simply counting Calories may help with awareness and bookkeeping, but may not be as accurate in our bodies as it is in the lab. We need to consider the composition of the food and the macronutients. Or simply follow my Food Rules and make it simple!

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