Take appointment of dietician in any clinic, and try to get their recommendations. Coz, I may need further details of the existing diabetic suger level both in fasting and after meal, also how long the problem exist with you, and your nationality that helps to provide you the meal appropriate your food style etc. is vital information., In addition to that, are you type 1 diabetic or type 2., and do you take any medicines and how long ? and what other problem do you have if any in addition to diabetc disorder all that factor also I need to know about it.
I do recommend you to go for always with salads, and high fiber content foods, and repetation of food intake in 5 times in stead of three meals moderate level.

lemon juice can be taken. and leban drink etc. is harmless. Diabetic is a honourable desease, if not respected, this ailment will make havoc in the life therefore, try to honour your exisiting sickness with medicine, food intake and exercise so that you may go healthy for a long time without complication.