How many calories do you think you burn on these rides vs consume during the rides?
To offer another perspective (I really don't keep track of the amount of calories I consume to be frank, I just keep eating).
Last 200km audax (DIY a fortnight ago) shows on Garmin Connect as a consumption of 3102 calories (these are kCal of course). This calculation depends on a doubtful algorithm but let's go for 3100 in 10 hours riding (9 hours pedalling).
Breakfast: Double porridge, with raisins, dates, syrup and banana before starting: 600+ calories (as opposed to 200 for a normal breakfast)
During day:
2 bananas (2 x 89 =) 178 calories
Peanut, cookie and raisin 'dip-in' mix on-the-go: about 600 calories
2 Clif bars (2 x 267 = ) 534 calories
Pasty (bought at single stop): 569 calories
So that's 2500 calories consumed against an outlay of 3100. An immediate sandwich (+other) at the end at home and I'm in balance and not over-hungry for supper. So as
@YukonBoy (NB he is supine, more aero and thus probably uses less calories per hour) says: "A good evening meal will make up the difference."
And on LEL 2017 I gained weight over the course of 100 hours, as the food was so good at every control: I ate a meal (two at Moffat and Louth) at every control except the first one (St Ives).