Bread swinging is a strategy designed to lower your turn count. You can swing manually by the v key. It takes 15 auts to swing a miscellaneous item, like a scroll, but only one turn. Therefore, you will have more time to regenerate health, while taking the same amount of turns.
An untrained weapon with high base delay, such as a heavy weapon, will swing slower and thus save more turns. However, note that taking off a shield and putting it back on again will take 10 turns (of 10 aut each).
This strategy has a relatively little impact on the number of turns taken, and zero impact outside of a speedrun. The insert key allows you to repeat an action over and over for this purpose.