ABSTRACT
The concept that some people metabolize energy sources more efciently than others is controversial. Many debates have focused on the question is a dietary kilocalorie for one person the same for another? Relevant to this question is the fact that research in the last 20 years has shown that the ef- ciency of the conversion of energy substrates to useful forms of cellular energy can vary greatly.1 The molecular origins of variable efciency in energy transduction in the context of obesity and successful weight loss are the subject of this chapter. Our research over the last decade has identied processes in the mitochondria that may explain some of the heterogeneity in obesity risk and in the response to hypocaloric diets.
