ST. LOUIS — Robert V. Vitale has been named president and chief executive officer of Post Holdings, Inc., one of several management moves unveiled as part of sweeping changes at the St. Louis-based consumer packaged goods holding company.

Effective Nov. 1, Mr. Vitale will take over as president and c.e.o., succeeding William P. Stiritz, who will continue at Post in the newly-created role of executive chairman. Mr. Vitale has been chief financial officer at Post since its formation in October 2011. He also has been named to Post’s board of directors.

Mr. Stiritz previously was chairman and c.e.o. of Post since the company separated from Ralcorp Holdings, Inc. in 2012. In connection with this new role, Mr. Stiritz’s employment agreement was extended to October 2017.

Terence E. Block, currently president and chief operating officer, has decided to retire from Post. Mr. Block also will retire from Post’s board of directors.

“Terry was instrumental in our start-up phase as we separated from Ralcorp,” Mr. Stiritz said. “I understand his decision, and I wish him very well as he enters this stage of life.”

In addition to the personnel changes, Post said it will be reorganizing its business around three distinct groups. Post’s newly formed Consumer Brands Group includes the legacy Post Foods cereal operations as well as the recently acquired active nutrition businesses of Premier Nutrition Corp., Dymatize Enterprises and the PowerBar and Musashi brands. James L. Holbrook has been named president and c.e.o. of the Consumer Brands Group. Mr. Holbrook has been executive vice-president of marketing at Post since October 2011 and president of Post Foods since January 2014.

The Michael Foods Group now is comprised of the Michael Foods’ egg, cheese and potato businesses, which Post acquired in June 2014, and Dakota Growers Pasta Co., which was acquired in January 2014. It will be headed by James E. Dwyer Jr. as president and c.e.o. Mr. Dwyer has led Michael Foods since 2009.

Mr. Holbrook and Mr. Dwyer also have been named executive vice-presidents of Post Holdings, Inc.

Post’s remaining businesses, consisting of Golden Boy Foods and Attune Foods, will comprise the Private Label Group. This Group will report directly to Mr. Vitale.

“The most valuable asset a company can have is a management team capable of adapting to a changing environment,” Mr. Stiritz said. “I feel very confident moving into the next stage of our development. This team is among the best I have seen.”

Commenting on the changes, Mr. Vitale said, “I appreciate the confidence that Bill and the board have shown in this team. Post’s prospects are exciting. Under Jim Holbrook’s leadership Post Foods has made remarkable progress, and adding the active nutrition brands to Jim’s group gives him the ability to deploy the resources of the Post organization against a larger opportunity. Meanwhile, under Jim Dwyer, we have one of the premier food service businesses in the country in Michael Foods, with exciting expansion opportunities. I look forward to working with Bill, Jim and Jim to build upon Post’s great history.”