TLDR: that doesn’t happen during training at all.
Longer version:
The ability of the human body to burn through glycogen during exercise, and immediately lower blood glucose as a result is amazing! During training sessions like that, GLUT4 (rhymes with “scoot”) is upregulated/activated. GLUT4 is a transport protein that exists mostly dormant in muscles until exercise happens, or you eat a donut (or other sugar). GLUT4’s sole job is to act as a vacuum for muscle cells to suck glucose out of the bloodstream and into the working muscle. Exercise is the number 1 way to activate GLUT4 and make all those vacuums present on the muscle cell membrane turn “on” and do their job (rather than sitting idle and dormant deep inside each cell). They remain highly active for at least 30 minutes post-exercise. It also exists in the liver, which is how you get carbs converted to fat (bad for body composition!) but interestingly, and importantly, the GLUT4 in the liver stays relatively dormant during exercise while the muscle cells get to vacuum up all the sugar in the blood.
The application of this GLUT4 activation is that any sugar you consume will be sucked up by the muscles and prevented from circulating your bloodstream and causing inflammation, or causing insulin to spike and remain high until the liver turned it into fat. There will be NO fat generation or chronic low-grade inflammation caused by that rapid sugar influx, so long as it’s either during exercise or immediately post-exercise.
Now, if you were to consume sugar in higher doses around the clock… then you’d have problems. Ironically, consumption of sugar during and immediately post-exercise may actually improve body composition because the storage of muscle glycogen in muscles (glycogen = storage form of carbs) is a fat-burning process AND muscles that are stocked with glycogen tend to build more muscle proteins at rest which is also fat-burning and blood-sugar-reducing.