The Effects Of Intensive Weight Loss On Metabolome In Female Fitness Competitors: 2486 Board #1 June 1 1 00 PM - 3 00 PM

Intensive weight reduction has become popular in many performance and aesthetic sports. However, health effects of prolonged semi-starvation are scarcely studied in a longitudinal, systems biology setting. PURPOSE: The aim of our study was to examine how intensive weight loss with large amount of exercise affects system biological pathways and health related biomarkers in female fitness/physique athletes aiming for low body fat while maintaining their lean mass. METHODS: The study population consisted of healthy fitness/physique athletes divided in Diet (n=25) and Control (n=17) group. The study included three time point measurements: before the weight loss period (PRE), after the 19.8±3.6 weeks of weight loss period (MID) and after the 17.5±2.6 weeks of recovery period (POST). Control- group was instructed to maintain their usual fitness lifestyle, exercise levels and energy intake constant during the study. NMR-platform was used for the determination of metabolome. Data analysis was performed using R and significance threshold was set to 2.1x10^-3. RESULTS: Intensive weight loss in the Diet-group was composed of mainly large (~51 %) decreases in total body fat mass (p <0.001) waist circumference (~8 %) and the android region (~70 %) reflecting visceral fat mass (p < 0.001). This was accomplished by decreased energy intake (~18 %) and increased total amount (METh) of exercise (~15 %). Weight loss affected significantly on several inflammation related biomarkers such as α1–acid glycoprotein (p=2.47x10^-9) and various HDL-metabolites (p=8.22x10^-12). The reduction of visceral fat mass was significantly associated with the observed changes in lipid and inflammation biomarker concentration after adjusting for confounding factors. All detected changes in metabolome were reversed back to baseline levels during the recovery period. No changes were observed in the controls. CONCLUSIONS: Intensive weight reduction has positive, but temporary effects on serum metabolome in fitness/physique athletes. Decrease in visceral fat mass seem to explain majority of these effects of weight reduction on lipid profile and inflammation related biomarkers. Supported by Academy of Finland (grant No. 275922 to JH and No. 269517 to MP), Finnish Fitness Sports Association and Department of Biology of Physical Activity.