Should we say "Bismillah Al-Rahman Al-Rahim" when eating, or is "Bismillah" sufficient?

"Tasmiyah" over food means saying "Bismillah" (In the name of Allah) at the beginning of eating. If one forgets at the beginning, they should say: "Bismillah fi awwalihi wa akhirihi" (In the name of Allah, in its beginning and its end). It is preferable to say: "Bismillah Ar-Rahman Ar-Rahim" (In the name of Allah, the Most Gracious, the Most Merciful), but saying "Bismillah" is sufficient to fulfill the Sunnah.