Citymapper is a city-wide route-planning app which provides a comprehensive list of options for your route, taking you from A to B using your mobile connection to navigate through to your destination.
The app homepage displays a small map of your location including an inset tube map. From your current location you can view travel options within 5 minutes walk. If you select to walk or cycle, Citymapper will tell you how many calories you will burn and the equivalent in food. e.g. half a chocolate bar or one bacon butty