Methodologies in energy expenditure

Measurements of basal or resting energy expenditure by indirect calorimetry and total energy expenditure by isotope tracer studies are now routine and offer a high degree of precision and accuracy for measurements of energy expenditure in individuals or small groups. Together they have provided important information with respect to the energy needs of lean and obese subjects, the effects of diet, exercise and pharmacological interventions. Given the current interest in physical activity as a determinant of health it seems probable that in the next few years there will be particular interest in the development of more widely applicable methods which can estimate both the energy cost of physical activity and aspects of exercise behaviour in large groups or population studies. As the research questions change, so must the methodology.