Imam Ali (A.S.)‏

الْمَعِدَةُ بَيْتُ الْأَدْوَاءِ وَ الْحِمْيَةُ رَأْسُ الدَّوَاءِ لَا صِحَّةَ مَعَ النَّهَمِ.

The stomach is the house of all ailments, and diet control is the fountainhead of remedies. Verily, health and overeating cannot be together.

Bihar al-Anwar, vol. 59, pg. 75