QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended									12 Months Ended
		Aug. 01, 2020	[1]	May 02, 2020	Feb. 01, 2020	Nov. 02, 2019	Aug. 03, 2019	Apr. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Aug. 01, 2020		Aug. 03, 2019		Jul. 28, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net sales		$ 6,754,555		$ 7,031,718	$ 6,431,382	$ 6,296,612	$ 6,731,294	$ 6,247,462	$ 6,449,542	$ 2,879,158	$ 26,514,267	[1]	$ 22,307,456		$ 10,226,683
Gross profit		1,000,024		1,050,232	917,325	907,211	968,979	922,173	898,087	419,367	3,874,792	[1]	3,208,606		1,520,014
Net (loss) income from continuing operations		52,962		94,447	(13,984)	(387,434)	21,806	56,493	(344,241)	(19,579)	(254,009)	[1]	(285,521)		162,777
(Loss) income from discontinued operations, net of tax		926		(4,078)	(16,076)	4,026	(2,386)	651	2,345	288	(15,202)	[1]	898	[2]	0
Net (loss) income including noncontrolling interests		53,888		90,369	(30,060)	(383,408)	19,420	57,144	(341,896)	(19,291)	(269,211)	[1]	(284,623)		162,777
Net (loss) income attributable to United Natural Foods, Inc.		$ 52,366		$ 88,131	$ (30,710)	$ (383,927)	$ 19,197	$ 57,092	$ (341,725)	$ (19,294)	$ (274,140)		$ (284,730)		$ 162,777
Basic (loss) earnings per share:
Continuing operations (in dollars per share)		$ 0.94		$ 1.72	$ (0.27)	$ (7.29)	$ 0.41	$ 1.11	$ (6.77)	$ (0.39)	$ (4.81)	[1]	$ (5.57)		$ 3.22
Basic (loss) earnings per share (in dollars per share)		0.96		1.64	(0.57)	(7.21)	0.36	1.12	(6.72)	(0.38)	(5.10)	[1]	(5.56)		3.22
Diluted (loss) earnings per share:
Continuing operations (in dollars per share)		0.88		1.67	(0.27)	(7.29)	0.41	1.11	(6.77)	(0.39)	(4.81)	[1]	(5.57)		3.20
Diluted (loss) earnings per share (in dollars per share)		$ 0.89		$ 1.60	$ (0.57)	$ (7.21)	$ 0.36	$ 1.12	$ (6.72)	$ (0.38)	$ (5.10)	[1]	$ (5.56)		$ 3.20
Retained Earnings
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net (loss) income attributable to United Natural Foods, Inc.	[1]										$ (274,140)

[1] Fiscal 2020 results reflect 52 weeks of operating results, as compared to fiscal 2019 53 weeks. The fourth quarter of fiscal 2020 includes 13 weeks and the fourth quarter of fiscal 2019 contains 14 weeks.

[2] These results reflect retail operations from the Supervalu acquisition date of October 22, 2018 to August 3, 2019.