According to a fatwa of Shaikh Uthaymeen of Saudi Arabia it is bid'ah to stop eating 10 or 15 minutes before expiry of Suhoor time.

Answer

It is permissible to eat right until a second before expiry of Sehri/Suhoor time. However, since in most places the exact time is not known because Subh Saadiq is not physically determined by sighting the natural phenomena, stopping eating a few minutes before what is thought to be Subh Saadiq is a precautionary measure. Undoubtedly, it will be haraam and bid'ah to believe that it is not permissible to eat right until just before entry of Subh Saadiq. To the best of our knowledge no one holds such a belief. The cessation of eating is only precautionary. The Shaikh could not have meant that it is bid'ah to abstain from eating 15 minutes before Subh Saadiq. Perhaps he understood that people believe that it is Waajib to stop eating 15 minutes before Subh Saadiq and not permissible to eat thereafter.