For decades, the prevailing nutritional wisdom was based on what was called the "energy balance" equation. We take in calories from food; we burn up calories in the process of living (more on that in a moment). When calories in equal calories out, our weight stays pretty much the same.

I call this model the "bankbook" model. Take in more money than you spend, and you have a savings account. Spend more than you take in, and your checks bounce; you've got to dip into your savings to cover the expenses. Substitute money for calories and you get the picture. Your "savings" account is your fat.

This model has been the predominant model of weight control for the better part of the century. Most "diet" programs throughout this century, and certainly those prior to the last decade or so, have been based on calorie counting. But the idea that calories tell the whole story has been seriously and persuasively questioned in the last decade. This is one of the biggest philosophical differences between the mainstream and the "rogues."

I'm not going to go into why so many really smart people think that the energy equation (calories in, calories out) doesn't tell the whole story when it comes to weight control. We'll be talking about those issues throughout the year. For now, let's just say that calories are important to know about, but they don't give us the whole picture.

Next week, in part two of this series, I'll give you some basic formulas with which you can estimate your own Basal Metabolic Rate.