Hi, yes eating before testing would increase the glucose levels in the body. Only carbohydrates (including grain products, fruits, juice, milk, yogurts, potatoes, corns--starchy foods) will raise the blood sugar level in the body. However, if you didn't fast (have not eaten for 8 hours or more), you must had a random glucose test done. they do have guidelines to tell what number is high. if your glucose level came up to be a bit above normal then you might be considered prediabetic.