Exhibit 23.1

Consent of Independent Registered Public Accounting Firm

The Board of Directors

Nutrisystem, Inc.:

We consent to the incorporation by reference in the registration statements (Nos. 333-124561, 333-117781 and 333-110772) on Form S-3 and registration statements (Nos. 333-184460, 333-181740, 333-150893, 333-44908, 333-134215, 333-119009 and 333-218920) on Form S-8 of Nutrisystem, Inc. of our reports dated February 28, 2018, with respect to the consolidated balance sheets of Nutrisystem, Inc. and subsidiaries as of December 31, 2017 and 2016, and the related consolidated statements of operations, comprehensive income, stockholders’ equity, and cash flows for each of the years in the three-year period ended December 31, 2017, and the related notes (collectively, the “consolidated financial statements”), and the effectiveness of internal control over financial reporting as of December 31, 2017, which reports appear in the December 31, 2017 annual report on Form 10-K of Nutrisystem, Inc. Our report on the consolidated financial statements refers to a change in the accounting for excess tax benefits from share-based payment transactions.