Eating disorders are extremely common in endurance sports. I admit I have used bicycling solely in the pursuit of anorexia and bulimia related goals. A sick person seeking more sickness looks at the amount of calories burned while bicycling/running/endurance sports in general and ends up wasting hours of every day suffering, because they have found the holy grail exercise/punishment/caloric correction.
Have I ever thrown up on a ride due to bulimia? No, riding was for when I couldn't puke. Riding WAS the purging, no fun in it at all, max effort until you pull something or your pass out (which ever comes first) because your FAT look at you everyone is staring at you FATTY IN THE BIKE LANE. I hope your friend who through up the bananas is doing better. No one deserves to have their lives ruined by ED, especially the finer things in it like bicycling.