You stopped for a drink and some fuel.
Let me guess. The fuel was refined sugar based. (lucozade sport)
Lets see. You are running along with perfectly balanced blood sugar levels. You start feeling a bit hungry so instead of running through it and burning the fat you have a sugar bomb snack.
Your system is instantly flooded with sugar. Too much sugar. But because your body still has the ability to balance this out, it floods your system with insulin in an attempt to bring the level of blood sugar down to a safe level.
Unfortunately because its a delayed reaction, the insulin can get overdone at which point you find yourself with a really low blood sugar level, going all dizzy etc.
So what do you do? of course, just whack yourself with another dose of sugar, to raise your blood sugar levels.
Once you are in this cycle, the only way to keep your system level is to spend your life with a gut full of sugar acting like a resevoir.
I understand this cycle can lead to diabetes.