A number of ex-players have claimed that England should play another bowler in the 50-over game following the loss to Australia on Sunday, but Giles believes that the current tactics will serve his team well.
"I've heard a lot about the balance of the side. Ben [Stokes] is playing as a third seamer and is an improving bowler, has good skills, can bowl mid 80s upwards and has that potential to do that job on its own," Giles told reporters during a press conference.
"Otherwise the balance is what we played at the Champions Trophy when we were very successful.
"Before the Champions Trophy against New Zealand we played five specialist bowlers and that didn't really work and that's when we brought Ravi [Bopara] back and since that time he's had a fantastic run in the side so I don't think we're just fiddling overs."
England meet Australia in the third ODI at Edgbaston on Wednesday.