Does tracking your food intake and your exercise habits help you lose and maintain weight? A recent paper by Burke et al, published in the Journal of the American Dietetic Association, reviews the collective research to date on the benefits of self-monitoring for weight loss.(1) Self-monitoring, from a complex systems perspective, represents feedback. Feedback is a process that allows a system to alter its behaviour or functions in order to achieve a desired outcome. Burke et al report a significant and consistent positive association between self-monitoring and weight loss across the 22 papers identified for inclusion in their analysis. Each of the papers reviewed by Burke et al investigated the effects of tracking three things: diet, physical activity, or body weight.
These three forms of self-monitoring fall into two distinct categories of feedback. Both calorie counting and logging physical activity provide feedback about an individuals behaviour. In other words, they provide information about the “input” into the system. Self-weighing, on the other hand, tracks the result of those behaviours, the “output”. This distinction is important – the time frame over which change may occur in an input may be significantly different compared to a change in an output.
For example, using a pedometer to measure the number of steps you have taken during the day provides immediate feedback. It allows you to assess if you’ve met your activity goal or not and to make immediate adjustments to your behaviour. Daily variability in body weight, generally attributed to changes in body water content, may be as great as 1.5% of body-weight.(2) Thus, assessment of a meaningful trend in body weight requires a longer time frame. An increase in the time represents a feedback delay. Feedback delays exert a strong influence over behaviour and may lead to oscillations in a system.(3) Changing the delay has important implications for the success of the feedback mechanism in helping produce the desired results (in this situation, weight loss).
Appropriately, Burke et al raise the important issue of identifying the optimal frequency that should be adopted for self-monitoring. Although the authors found that “more frequent self-monitoring was consistently and significantly associated with weight loss compared to less frequent self-monitoring”,(1) they note a gap in our present knowledge. Current research does not address what the optimal “dose” for self-monitoring should be in order to best support successful behaviour change.
In addition to determining what intensity, frequency, and duration of self-monitoring should be recommended to support weight loss, ensuring the monitored measure is meaningful to the individual is also crucial for the success of self-monitoring. For feedback to be effective, the individual must identify it as something that is important to them.(4) Consequently, feedback that supports weight loss success for one individual, may not work for another – illustrating again the complexity of the obesity problem.
Given that obesity is a complex problem, strategies beneficial for solving complex problems have the potential to be more effective in obesity treatment than traditional methods that focus on messages to the individual to eat less and move more. Although feedback is one of the defining characteristics of complex systems, it remains a poorly understood and under-utilized leverage point for intervention. To echo the conclusions of Burke et al,we now need to address the following questions: What should we track? How often should we track it? And what role can technology play in making tracking easy?
1. Burke LE, Wang J, & Sevick MA (2011). Self-monitoring in weight loss: a systematic review of the literature. Journal of the American Dietetic Association, 111 (1), 92-102 PMID: 21185970
2. T. Khosla and W. Z. Billewicz (1964). Measurement of change in body-weight. British Journal of Nutrition, 18, pp 227-239 doi:10.1079/BJN19640022
3. Meadows D.H. (2008). Thinking in Systems. A Primer Ed. Diana Wright. White River Junction, VT: Chelsea Green Publishing.
4. Wheatley, M.J. and M. Kellner-Rogers (1999) What do We Measure and Why? Questions About The Uses of Measurement. Journal for Strategic Performance Measurement.
For another perspective reviewing the same article, also check out Dr. Sharma’s Obesity Notes: How Effective is Self-Monitoring in Weight Management?