Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Aug. 01, 2020	Sep. 24, 2020	Jan. 31, 2020
Cover [Abstract]
Document Type	10-K
Document Period End Date	Aug. 01, 2020
Document Transition Report	false
Entity File Number	001-15723
Entity Registrant Name	UNITED NATURAL FOODS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	05-0376157
Entity Address, Address Line One	313 Iron Horse Way,
Entity Address, City or Town	Providence,
Entity Address, State or Province	RI
Entity Address, Postal Zip Code	02908
City Area Code	401
Local Phone Number	528-8634
Title of 12(b) Security	Common stock, par value $0.01
Trading Symbol	UNFI
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Annual Report	true
Entity Shell Company	false
Entity Public Float			$ 379.5
Entity Common Stock, Shares Outstanding		54,839,901
Entity Central Index Key	0001020859
Current Fiscal Year End Date	--08-01
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false