Short Communication

International Journal of Obesity (2013) 37, 1611–1613; doi:10.1038/ijo.2013.51; published online 30 April 2013

Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule

D M Thomas1, C K Martin2, S Lettieri3, C Bredlau4, K Kaiser5, T Church2, C Bouchard2 and S B Heymsfield2

  1. 1Center for Quantitative Obesity Research, Department of Mathematical Sciences, Montclair State University, Montclair, NJ, USA
  2. 2Pennington Biomedical Research Center Baton Rouge, Baton Rouge, LA, USA
  3. 3Department of Computational and Systems Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA
  4. 4Department of Computer Science, Montclair State University, Montclair, NJ, USA
  5. 5Office of Energetics, Dean’s Office, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA

Correspondence: Dr DM Thomas, Center for Quantitative Obesity Research, Department of Mathematical Sciences, Montclair State University, Montclair, NJ 07043, USA. E-mail:

Received 10 December 2012; Revised 4 March 2013; Accepted 10 March 2013
Accepted article preview online 8 April 2013; Advance online publication 30 April 2013



Despite theoretical evidence that the model commonly referred to as the 3500-kcal rule grossly overestimates actual weight loss, widespread application of the 3500-kcal formula continues to appear in textbooks, on respected government- and health-related websites, and scientific research publications. Here we demonstrate the risk of applying the 3500-kcal rule even as a convenient estimate by comparing predicted against actual weight loss in seven weight loss experiments conducted in confinement under total supervision or objectively measured energy intake. We offer three newly developed, downloadable applications housed in Microsoft Excel and Java, which simulates a rigorously validated, dynamic model of weight change. The first two tools available at, provide a convenient alternative method for providing patients with projected weight loss/gain estimates in response to changes in dietary intake. The second tool, which can be downloaded from the URL, projects estimated weight loss simultaneously for multiple subjects. This tool was developed to inform weight change experimental design and analysis. While complex dynamic models may not be directly tractable, the newly developed tools offer the opportunity to deliver dynamic model predictions as a convenient and significantly more accurate alternative to the 3500-kcal rule.


3500-kcal rule; Wishnofsky’s rule; dynamic model; energy balance; first law of thermodynamics

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