ORIGINAL ARTICLES  EPIDEMIOLOGY AND CLINICAL MEDICINE 

The Journal of Sports Medicine and Physical Fitness 2016 January-February;56(1-2):105-113

Copyright © 2016 EDIZIONI MINERVA MEDICA

language: English

Does running with or without diet changes reduce fat mass in novice runners? A 1-year prospective study

Rasmus O. NIELSEN ^{1, 2}, Solvej VIDEBAEK ¹, Mette HANSEN ¹, Erik T. PARNER ³, Sten RASMUSSEN ², Henning LANGBERG ⁴ ✉

¹ Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark; ² Orthopaedic Surgery Research Unit, Science and Innovation Center, Aalborg University Hospital, Aalborg, Denmark; ³ Section of Biostatistics, Department of Public Health, Aarhus University, Aarhus, Denmark; ⁴ Section of Social Medicine, Department of Public Health, Danish Aging Research Center, University of Copenhagen, Copenhagen, Denmark.

BACKGROUND: The aim of this study was to explore how average weekly running distance, combined with changes in diet habits and reasons to take up running, influence fat mass.
METHODS: Fat mass was assessed by bioelectrical impedance at baseline and after 12 months in 538 novice runners included in a 1-year observational prospective follow-up study. During follow-up, running distance for each participant was continuously measured by GPS while reasons to take up running and diet changes were assessed trough web-based questionnaires. Loss of fat mass was compared between runners covering an average of 5 km or more per week and those running shorter distances.
RESULTS: Runners who took up running to lose weight and ran over 5 km per week in average over a one-year period combined with a diet change reduced fat mass by -5.58 kg (95% CI: -8.69; -2.46; P<0.001). Compared with subjects also running over 5 km per week but without diet changes, the mean difference in fat mass between groups was 3.81 kg (95% CI: -5.96; -1.66; P<0.001). A difference of -3.55 kg (95% CI: -5.69; -1.41; P<0.001) was found when comparing with those running less than 5 km per week and making changes to their own diet.
CONCLUSIONS: An average running distance of more than 5 km per week in runners who took up running to lose weight combined with a targeted diet change seems effective in reducing fat mass over a one-year period among novice runners. Still, randomized controlled trials are needed to better document the effects of self-selected diet changes.