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Proportional Feedback Control of Energy Intake During Obesity Pharmacotherapy
Author(s) -
Hall Kevin D.,
Sanghvi Arjun,
Göbel Britta
Publication year - 2017
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1002/oby.21978
Subject(s) - obesity , medicine , placebo , energy balance , pharmacotherapy , exponential function , exponential growth , drug , constant (computer programming) , endocrinology , mathematics , pharmacology , physics , computer science , mathematical analysis , alternative medicine , pathology , thermodynamics , programming language
Objective Obesity pharmacotherapies result in an exponential time course for energy intake whereby large early decreases dissipate over time. This pattern of declining drug efficacy to decrease energy intake results in a weight loss plateau within approximately 1 year. This study aimed to elucidate the physiology underlying the exponential decay of drug effects on energy intake. Methods Placebo‐subtracted energy intake time courses were examined during long‐term obesity pharmacotherapy trials for 14 different drugs or drug combinations within the theoretical framework of a proportional feedback control system regulating human body weight. Results Assuming each obesity drug had a relatively constant effect on average energy intake and did not affect other model parameters, our model correctly predicted that long‐term placebo‐subtracted energy intake was linearly related to early reductions in energy intake according to a prespecified equation with no free parameters. The simple model explained about 70% of the variance between drug studies with respect to the long‐term effects on energy intake, although a significant proportional bias was evident. Conclusions The exponential decay over time of obesity pharmacotherapies to suppress energy intake can be interpreted as a relatively constant effect of each drug superimposed on a physiological feedback control system regulating body weight.