Reference: Fataawa Ramadhaan – Volume 2, Page 543, Fatwa No.522
Fataawa as-Siyaam – Page 46
Question: Is there any difference of opinion regarding the invalidation of the fast by eating and drinking?
Response: Eating and drinking invalidates [the fast] by consensus; Indeed the basic principle behind fasting is to abstain from food and drink, and because of that, Allaah (Subhaanahu wa Ta’aala) has mentioned it in His statement:
{…and eat and drink until the white thread (light) of dawn appears to you distinct from the black thread (darkness of night)…}, [Soorah al-Baqarah, Aayah 187]