It seems that the heavier you are, the greater your brain perceives distances to be. Tests showed that a person weighing 23 stone sees objects as being twice as far away as someone weighing just nine stone.
The effect also applies to hill gradients. For a heavier individual, a hill will appear steeper than it does to a slim neighbour - another reason for taking the lift instead of the stairs.
Psychologist Dr Jessica Witt, from Colorado State University in the US, said: “Effort and performance influences perception.
“People who weigh more than others see distances as farther and hills as steeper, the idea being that if you have to carry this extra load that also impacts your perception.”