Stop! Do your maths before putting that Christmas mince pie in your mouth: – one mince pie = 360 calories – a 75kg woman uses 58 calories to walk 1km at her self-selected “walking for exercise pace” – therefore, to burn one mince pie, a 75kg woman has to walk 6.2km The figures are based on the unappetising fact that to burn 1kg of fat a healthy weight woman of 62kg would have to walk for 24.3 hours.