The first and foremost indicator is that there is enough source material for producing one more season of the anime. Fortunately, the original manga series contains twenty-six volumes consisting of 226 chapters as of now. The last, 26th Volume was issued on September 4, 2017. The manga is currently ongoing, besides. Season 1 of Food Wars!: Shokugeki no Souma covered the first eight volumes, while the second season served as an adaptation for the next seven volumes. Finally, the current season, which started with chapter 118, will end somewhere closer to Volume 20. As a result, there remain at least six volumes to adapt. Given the fact that about two volumes are issued within two months, there would be enough source materials by the end of the third season of Food Wars.
Our next indicator is such a brilliant reception which the anime has received from the target audience. Though we can't consider this factor a primary, at least in Japan, it nonetheless fully reflects the opinion of the viewers. Shokugeki no Souma Season 1 has a score of 8.56/10 according to > 295,000 votes on MyAnimeList. A sophomore season has a rating of 8.46/10 ~ 182,700 votes. This figure is a bit lower but still pretty high. Finally, the current score for Season 3 is 8.59/10 ~ 21,000 votes. This value is even higher compared to the same of Season 1. Thus, the show is incredibly popular. Moreover, its popularity keeps on rising.
Finally, we might look up at the BD/DVD sales of the series. On an average, about 800 items are sold per week. This indicator is not impressive, actually, but it is enough to cover the expenses. Summing up, all the numbers presented above point out that Food Wars!: Shokugeki no Souma would return for Season 4 in the foreseeable future. We just need to wait for the official announcement, to find out the exact release date. We'll speculate on the subject a bit below.
Shokugeki no Souma premiered in April 2015 on TBS. Soon, MBS, CBC, BS-TBS, and other Japanese broadcasters began airing the anime. J.C.Staff Co., Ltd. acted as a developer of the television adaptation. Sentai Filmworks has acquired rights for the series in North America. A second season kicked off on July 2, 2016. The current installment debuted on October 4, 2017. The first consisted of twenty-four episodes, while the second one contained only thirteen. The current season is ongoing and will come to an end someday in March of 2018. There has been no official news about the fourth installment as of yet. However, we are confident that the announcement appears soon.