HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 291/1/E23    most recent 00523.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Hall, K. D. Search for Related Content PubMed PubMed Citation Articles by Hall, K. D.

Computational model of in vivo human energy metabolism during semistarvation and refeeding

Laboratory of Biological Modeling, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland

Submitted 28 October 2005 ; accepted in final form 22 January 2006

Changes in body weight and composition are the result of complex interactions among metabolic fluxes contributing to macronutrient balances. To better understand these interactions, a mathematical model was constructed that used the measured dietary macronutrient intake during semistarvation and refeeding as model inputs and computed whole body energy expenditure, de novo lipogenesis, and gluconeogenesis as well as turnover and oxidation of carbohydrate, fat, and protein. Published in vivo human data provided the basis for the model components that were integrated by fitting a few unknown parameters to the classic Minnesota human starvation experiment. The model simulated the measured body weight and fat mass changes during semistarvation and refeeding and predicted the unmeasured metabolic fluxes underlying the body composition changes. The resting metabolic rate matched the experimental measurements and required a model of adaptive thermogenesis. Refeeding caused an elevation of de novo lipogenesis that, along with increased fat intake, resulted in a rapid repletion and overshoot of body fat. By continuing the computer simulation with the prestarvation diet and physical activity, the original body weight and composition were eventually restored, but body fat mass was predicted to take more than one additional year to return to within 5% of its original value. The model was validated by simulating a recently published short-term caloric restriction experiment without changing the model parameters. The predicted changes in body weight, fat mass, resting metabolic rate, and nitrogen balance matched the experimental measurements, thereby providing support for the validity of the model.

body composition; mathematical model; weight loss

This article has been cited by other articles:

				M. Siervo, G. Fruhbeck, A. Dixon, G. R. Goldberg, W. A. Coward, P. R. Murgatroyd, A. M. Prentice, and S. A. Jebb Efficiency of autoregulatory homeostatic responses to imposed caloric excess in lean men Am J Physiol Endocrinol Metab, February 1, 2008; 294(2): E416 - E424. [Abstract] [Full Text] [PDF]