The peak can be any time from about an hour after first bite to any time after the 2 hour mark. It depends on the contents of the meal, the amount of fat, the type of carbs, and your own personal metabolism. When I was testing out meals I often tested at an hour, 90 minutes, 2 hours and if I wasn't coming down then I tested half hourly until I did. In my case, my peaks are somewhere between an hour and 90 minutes. It depends on whether you want to catch the actual peaks or see how long it takes to start dropping or reach your base level.