A system comprising a mobile terminal and an external device, the mobile terminal comprising: a terminal body; a display unit disposed on the terminal body configured to output an execution screen while a call function is being executed; a wireless communication unit configured to perform wireless communication with the external device that includes a first electrode unit; a second electrode unit (210, 220, 230, 211) arranged in the terminal body; and a controller configured to: receive, from the external device via the wireless communication unit, a wireless signal indication that the first electrode unit of the external device has come into contact with a part of a user's body; control the second electrode unit (210, 220, 230, 211) to apply a current in response to the wireless signal while the call function is being executed; obtain a body fat measurement using a voltage formed by the current flowing between the first electrode unit and the second electrode unit (210, 220, 230, 211) when the first electrode is in contact with the part of the user's body and the second electrode unit (210, 220, 230, 211) is in contact with another part of the user's body; compare the obtained body fat measurement result with a stored body fat measurement result; and output the obtained body fat measurement result on the execution screen when a difference between the compared measurement results is equal to or greater than a reference value or not output the obtained body fat measurement result when the difference between the compared measurement results is smaller than the reference value. a terminal body; a display unit disposed on the terminal body configured to output an execution screen while a call function is being executed; a wireless communication unit configured to perform wireless communication with the external device that includes a first electrode unit; a second electrode unit (210, 220, 230, 211) arranged in the terminal body; and a controller configured to: receive, from the external device via the wireless communication unit, a wireless signal indication that the first electrode unit of the external device has come into contact with a part of a user's body; control the second electrode unit (210, 220, 230, 211) to apply a current in response to the wireless signal while the call function is being executed; obtain a body fat measurement using a voltage formed by the current flowing between the first electrode unit and the second electrode unit (210, 220, 230, 211) when the first electrode is in contact with the part of the user's body and the second electrode unit (210, 220, 230, 211) is in contact with another part of the user's body; compare the obtained body fat measurement result with a stored body fat measurement result; and output the obtained body fat measurement result on the execution screen when a difference between the compared measurement results is equal to or greater than a reference value or not output the obtained body fat measurement result when the difference between the compared measurement results is smaller than the reference value. receive, from the external device via the wireless communication unit, a wireless signal indication that the first electrode unit of the external device has come into contact with a part of a user's body; control the second electrode unit (210, 220, 230, 211) to apply a current in response to the wireless signal while the call function is being executed; obtain a body fat measurement using a voltage formed by the current flowing between the first electrode unit and the second electrode unit (210, 220, 230, 211) when the first electrode is in contact with the part of the user's body and the second electrode unit (210, 220, 230, 211) is in contact with another part of the user's body; compare the obtained body fat measurement result with a stored body fat measurement result; and output the obtained body fat measurement result on the execution screen when a difference between the compared measurement results is equal to or greater than a reference value or not output the obtained body fat measurement result when the difference between the compared measurement results is smaller than the reference value.