All Calories Are Not Equal

After interviewing the authors of Why Calories Count, by Marion Nestle and Malden Neshein, New York Times writer, Mark Bittman, offers some interesting tidbits.

What is a calorie? - "a measure of the energy derived from a food source"

[Note:  Wikipedia is much more precise:

"Definitions of a calorie fall into two classes:

• The small calorie or gram calorie (symbol: cal)^[2] approximates the energy needed to increase the temperature of 1 gram of water by 1 °C. This is about 4.2 joules.
• The large calorie, kilogram calorie, dietary calorie, or food calorie (symbol: Cal)^[2] approximates the energy needed to increase the temperature of 1 kilogram of water by 1 °C. This is exactly 1,000 small calories or about 4.2 kilojoules. It is also called the nutritionist's calorie."]

Which foods have more calories?  - "A gram of fat has been determined to have nine calories and a gram of protein or carbohydrate four calories; so for any given measure, fat has more than twice as many calories as protein or carbs. Those numbers are not perfectly accurate, but they’re good enough."

Can you lose weight by eating fewer calories?  -  In clinical settings where all food is weighed and measured, yes.  But there are some problems such as:

". . . no one lives under experimental conditions, and foods are complicated mixtures: fiber makes a difference and form makes a difference.” (Fiber is special because it’s not digested or digested incompletely. Most of its calories don’t get into the body, which is one reason why fruits and vegetables, which are high in fiber, help with weight loss.)"

How does the body fight dieters?  

"It’s hard to lose weight, because the body is set up to defend fat, so you don’t starve to death; the body doesn’t work as well to tell people to stop eating as when to tell them when to start.”

The question everyone has:

“'What can I eat to keep from putting on weight?' and here the answer turns out to be not only easy but also expected." 

For that answer you have to go check out the article or read their book.  This is not just some pop diet book.  The lead author has a PhD in molecular biology and the book is published by University of California Press. 

And it gets political too.