I have had diabetes type 1 for 26 years now. I'm 35. I have had this problem for a while now. When I used to eat meals at same time and gave myself same amount of insulin and carbs for breakfast, lunch, dinner my sugars were more stable than they are now that I 'think' I know my insulin to carb ratio. But even this seems to change from week to week but could also be due to stress, phyical activity or eating food I haven't before and guessing the carbs arong. I sometimes think the carbs listed on the food packet is wrong as often my fluctuations make no obvious sense or have any reasoning behind them. Its very frustrating. I have spoken with my gp, nurse and doctor and dietician and they say this is normal for most diabetics but u have to ensure u correct the low or high. They give me no resolve but offer advice as to why it might happem. Its very hit and miss and leaves us at risk of complications.