[en] The p+p→π0+X inclusive reaction data of Carey et al. were studied in the framework of the ''scaling in the mean'' hypothesis first proposed by Dao et al. These data were used to obtain the gamma ray spectrum in terms of the average value of the Feynman variable < x>. A comparison with the observed gamma ray spectrum at Mt. Chacaltaya by the Japanese and Brazilian Group gives the energy dependence of < x> at very high energy. (author)