Food (ghidha) refers to the meal that is eaten at the beginning of the day. Since for the fasting person, the pre-dawn meal (suhoor) serves as the substitute for the day's meal, it has therefore been referred to as "food" (ghidha) in the noble hadith, just as in our language we may call suhoor "breakfast." (For further details, see Hadith: 2146)
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 2166