A:
Yes, it is Haram for Muslims to eat too much to the level that could harm them, because this is a kind of extravagance, and it is known that extravagance is Haram. Allah (Praised and Exalted be He) says:
O Children of Adam! Take your adornment (by wearing your clean clothes), while praying and going round (the Tawâf of) the Ka‘bah, and eat and drink but waste not by extravagance, certainly He (Allâh) likes not Al-Musrifûn (those who waste by extravagance).
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.