Charles Ellicott Commentary Daniel 10:3

"I ate no pleasant bread, neither came flesh nor wine into my mouth, neither did I anoint myself at all, till three whole weeks were fulfilled." — Daniel 10:3 (ASV)

Pleasant bread — that is, delicate food. Abstaining from this as well as from the use of oil (compare to 2 Samuel 12:20; Amos 6:6) were the outward signs of Daniel’s grief.