On 16 September 2011 the Catholic bishops in England and Wales  reinstated the obligation to abstain from eating meat on Fridays -  normally observed by eating fish in its place.  In doing so, they  returned to a practice that dates back to the very early days of  Christianity.  The stated aims of the bishops was to increase religious  practice and identity. While the obligation was reinstated in England and Wales, it was not in the rest of the UK, namely in Scotland and  Northern Ireland.  We use this quasi-experimental setting, where some Catholics in the UK were subjected to the obligation but others were  not, to measure its impact on consumption and religious practice and satisfaction. We find evidence of compliance with the obligation and that it coincides with increased religious observance and satisfaction.