I've been using the Map My Walk app but I'm not sure how accurate it is. New mum/enormous/c-section. My usual route is approx. 3.6 miles. I'm 108kg (bloody hell...) and 5'9". The app says I've burned 700 kcals doing this! When I googled the distance, 300-400 kcals were calculated. My route is very hilly countryside walk, could this account for extra calories or is this BS?