Physical activity and body weight maintenance: What is the molecular link?

• Applicant: Professor Dr. Mathias Treier
• Subject Area: Pediatric and Adolescent Medicine ; Endocrinology, Diabetology, Metabolism
• Term: from 2012 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 101434729

Reduced physical activity is a major component of the obesity epidemic and enforced physical activity has been shown to be beneficial for weight maintenance after caloric restriction by increasing energy expenditure. Energy expenditure of an organism is the result of 3 components: the basal metabolic rate that accounts for about 60% and is mainly determined by the weight of our muscles, thermogenesis (10%), which is required for food digestion, and overall physical activity (30%). From these three parameters physical activity is obviously the most variable one. However, the genetic and molecular factors that determine our physical activity are not well understood. Although it has been generally assumed that the metabolic state is the major parameter that influences our physical activity we could demonstrate that physical activity has a genetic component. The difficulties to maintain body weight after caloric restriction may thus be due to the fact that the weight gain in the first place was caused from reduced physical activity as a result of their genetic composition. Thus the weight regain after diet induced weight losses could be explained by a genetic drive towards a reduced physical activity leading to a vicious cycle In this proposal we therefore want to further delineate the molecular and genetic mechanisms and particularly the neuronal circuitries that regulate physical activity. Identification of the genetic components and molecular mechanisms that determine physical activity should allow us to identify polymorphisms in humans that predispose them to obesity due to genetic variations causing reduced physical activity. Furthermore, this knowledge might ultimately result in the development of targeted life style or targeted pharmacological intervention strategies for obese patients who have an unfavourable genetic composition with respect to their physical activity pattern leading to weight regain after caloric restriction.

• DFG Programme: Clinical Research Units
• Subproject of: KFO 218: Hormonal Regulation of Body Weight Maintenance
• Participating Person: Petra Wiedmer, Ph.D.