University of Pittsburgh, School of Education. Pittsburgh
Introduction/Objectives: Obesity is affecting many countries throughout the world. This is of significant public health concern because of the association between excess body weight and body fatness and numerous chronic health conditions. These include cardiovascular disease, diabetes, some forms of cancer, musculoskeletal disorders, and others. Thus, broad implementation of approaches to prevent and successfully treat obesity are needed. The cornerstone of these interventions rely on concepts of energy balance, the difference between energy intake and energy expenditure. While conceptually this appears to be simple, expend more energy than you consume, it is in reality rather complex. Development: Approaches to alter energy balance have relied on the altering energy intake, altering energy expenditure, or the combination of both of these. However, many of these approaches have considered energy balance from a static perspective, which suggests that altering one aspect of energy balance has little or no impact on other components of energy balance. This perspective is most likely not accurate as research now suggests that altering one component of energy balance may have an unanticipated impact on other components of energy balance. Moreover, there may be a high degree of variability in these responses between individuals. For example, altering energy balance the components of energy balance may alter energy intake, with some individuals responding by eating more and others responding by eating less. There may also be other physiological factors that contribute to energy balance and individual variability in energy balance. Conclusions: Successful approaches to achieving or altering energy balance need to consider the consequence of one component on the other components of energy balance. Thus, attempts to prevent or treat obesity through alterations in energy balance need to consider these dynamic factors. Simply encouraged reduced energy intake or increased physical activity may have limited impact on initial or long-term weight control success due to the interaction between energy intake and energy expenditure that exists. Public health approaches to successfully combat obesity need to take these factors into consideration. Key words: obesity, weight control, physical activity, exercise, diet.