Humans can walk for miles, solve problems and form complex relationships using the energy provided by daily meals. That is a lot of output for a fairly modest input. Listener Charlotte from the UK wants to know: how efficient are humans? How do they compare to cars, other animals and even to each other? Presenter Marnie Chesterton pits her energetic self against everything from cars to rabbits to find out how she shapes up. Marnie also explores whether humans are born equal when it comes to fuel efficiency. Does the energy from one banana get converted into the same amount of movement from person to person? Marnie gets on a treadmill to find out how efficient she really is. With contributors from Herman Pontzer, Duke University, Rhona Pearce, Loughborough University and Christian Gammelgaard Olesen from Wolturnus wheelchair manufacturing company. Presenter: Marnie Chesterton Producer: Caroline Steel Editor: Richard Collings Production co-ordinator: Jonathan Harris Art Design: Jonathan Harris Image credits: Airplane: Credit: Ghrzuzudu Creative #:1337512445 Red car: Credit: EgudinKa Creative #:625457854 Wheelchair Woman: Credit: Ponomariova_Maria Creative #:1401730072 Getty Images