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NJIT Mathematical Biology Seminar

Tuesday, April 11, 2006, 4:00 pm
Cullimore Hall 611
New Jersey Institute of Technology

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Computational model of human energy metabolism and the regulation of body weight

Kevin Hall

Laboratory for Biological Modeling, NIDDK
National Institutes of Health

Changes of body weight and composition (i.e., fat and lean tissue masses) are the result of complex interactions among whole-body metabolic fluxes. To better understand these interactions, a mathematical model was constructed that uses dietary intake as model inputs and computes whole-body energy expenditure, de novo lipogenesis, gluconeogenesis, as well as turnover and oxidation of carbohydrate, fat and protein. Published in vivo human data provided the basis for simple sub-models of individual physiological processes which were then integrated by fitting a few unknown parameters to the classic Minnesota human starvation experiment. The model accurately simulated the measured body weight and fat mass changes during 6 months of semi-starvation as well as the subsequent re-feeding period and predicted the unmeasured metabolic fluxes underlying the body composition changes. Furthermore, the model explained the mysterious rapid rebound and overshoot of body fat mass observed during re-feeding that had previously generated much speculation in the obesity community. Without changing the model parameters, the model also compared favorably to independent measurements of human metabolism and body composition changes during both under-feeding and over-feeding. I will discuss these findings and the application of the model to the study of conditions such as obesity and cancer cachexia.