Physical versus psychosocial measures of influences on human obesity. Comment on Dhurandhar et al

Eminent colleagues in research on energy balance and human obesity, including the two Editors of this journal, argue that research participants’ reports of their own food intake and physical activity should be replaced by monitoring instruments that generate data automatically.1 This proposal has two fundamental flaws. Both basic deficiencies in research on human obesity can be overcome by objective verbal data developed in psychological science. The first flaw is that the everyday actions that need to measured are liable to be changed by awareness that they are being monitored. The second basic flaw is that physics and chemistry cannot capture the societally objective patterns in human ingestion and movement. Choices of foods and drinks, as well as exercising or resting, and keeping warm or cool, are all actions construed in words by a community. The identity of each habitual practice is specifiable only by a culture’s consensus on descriptions of the observed activities. Fundamental scientific evidence from life in the locality is needed in order to determine the amount of weight change caused by a persisting change in frequency of a recognised habit.