@clingclang - It's a good idea to keep a Food & Blood Sugar Diary, over time you will see which foods give you spikes in blood sugars. Keep a record of your blood sugar before meals and test 2 hours after eating and record the contents of that meal.
Be careful what you eat, snacking and eating sugary foods/carbohydrates can affect blood sugars. Foods that cause "spikes" are called White Carbohydrates: Rice, Pasta, Bread, Potatoes, Cakes, Pastries, Biscuits.
Eat Proteins, Fats, Veg and non-tropical Fruit in your diet. Exercise also helps to lower blood sugars. A lot of forum members follow LCHF Diet have a look/read at the following:
http://www.dietdoctor.com/low-carb/60-seconds