Hadith 31-129

وَبِهذَا الإِسنادِ عَنْ عَلِىِّ بْنِ أَبِي طالِبٍ‏ عَلَيْهِ السَّلامُ قالَ: عَلَيْكُمْ بِاللَّحمِ، فَإِنَّهُ يُنبِتُ اللَّحْمَ، وَمَن تَرَكَ اللَّحْمَ أَرْبَعِينَ يَوْماً ساءَ خُلقَهُ.

According to the same documentation, Ali ibn Abi Talib (a.s.) said, “I advise you to eat meat since it will strengthen your muscles. Whoever abstains from eating meat for forty days will get bad-tempered.”