RT Journal Article SR Electronic T1 Physical activity guidelines for weight loss: global and national perspectives JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 1235 OP 1236 DO 10.1136/bjsports-2015-095863 VO 50 IS 20 A1 Leon Mabire YR 2016 UL http://bjsm.bmj.com/content/50/20/1235.abstract AB