Flowers Foods (FLO) could be a solid addition to your portfolio given a notable revision in the company's earnings estimates. While the stock has been gaining lately, the trend might continue since its earnings outlook is still improving.Analysts' growing optimism on the earnings prospects of this bakery goods company is driving estimates higher, which should get reflected in its stock price. After all, empirical research shows a strong correlation between trends in earnings estimate revisions and near-term stock price movements. Our stock rating tool -- the Zacks Rank -- has this insight at its core.The five-grade Zacks Rank system, which ranges from a Zacks Rank #1 (Strong Buy) to a Zacks Rank #5 (Strong Sell), has an impressive externally-audited track record of outperformance, with Zacks #1 Ranked stocks generating an average annual return of +25% since 2008.For Flowers Foods, strong agreement among the covering analysts in revising earnings estimates upward has resulted in meaningful improvement in consensus estimates for the next quarter and full year.The chart below shows the evolution of forward 12-month Zacks Consensus EPS estimate:12 Month EPSCurrent-Quarter Estimate RevisionsThe company is expected to earn $0.25 per share for the current quarter, which represents a year-over-year change of +15.15%.The Zacks Consensus Estimate for Flowers Foods has increased 16.92% over the last 30 days, as three estimates have gone higher compared to no negative revisions.Current-Year Estimate RevisionsThe company is expected to earn $1.22 per share for the full year, which represents a change of +27.08% from the prior-year number.The revisions trend for the current year also appears quite promising for Flowers Foods, with three estimates moving higher over the past month compared to no negative revisions. The consensus estimate has also received a boost over this time frame, increasing 11.93%.Favorable Zacks RankThanks to promising estimate revisions, Flowers Foods currently carries a Zacks Rank #2 (Buy). The Zacks Rank is a tried-and-tested rating tool that helps investors effectively harness the power of earnings estimate revisions and make the right investment decision. You can see the complete list of today's Zacks #1 Rank (Strong Buy) stocks here.Our research shows that stocks with Zacks Rank #1 (Strong Buy) and 2 (Buy) significantly outperform the S&P 500.Bottom LineWhile strong estimate revisions for Flowers Foods have attracted decent investments and pushed the stock 11.9% higher over the past four weeks, further upside may still be left in the stock. So, you may consider adding it to your portfolio right away.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Flowers Foods, Inc. (FLO): Free Stock Analysis Report To read this article on Zacks.com click here.