Taking nutrition while in aero

I think this depends on a few things: race distance, elevation changes of the course, your comfort level while in aero, potential soreness if your neck/lower back. For shorter races (sprint/Oly), I think it is detrimental to sit up to take in nutrition. The races are too short to give up the aero advantage. For halfs and fulls, I think it is almost necessary to stretch your back/neck. Some may be able to maintain aero for 2-5 hours, but I am not one of those.

Hope this helps.

For short races, I don't usually sit up. (I don't take in any nutrition on a sprint, so it's a moot point.) I wouldn't normally sit up for the one gel I usually take on the bike in an Oly, unless there was some other reason (like getting out a water bottle--it's so hot here that I can't just rely on the aerobottle for Oly but need to have a bottle on my tube as well), avoiding livestock or small children wandering onto the course, going up/down a steep hill, etc. I just stay in aero as much as possible. Personally I don't find it that hard to stay in aero for 3+ hours, but there are times when safety, if nothing else, makes it advisable to sit up!

I always stay in aero whether training or on races when taking nutrition. I feel like I exert a lot more energy when off the aero bars so it's just easier to stay down. I have to deal with a lot of wind down here in the Keys so I guess I'm just conditioned to it. Also, I personally find aero more comfortable. I do think it's a bit risky though so I'm curious what the consensus is.

Depends on the distance. For sprints, I'll take a gel before the start and that will bring me to the finish line, so nothing on the bike (or on the course for that matter). For Oly, I'll take a gel on the bike, but I do sit up for that, gives me a chance to stretch out once during the race and the time loss is easily made up by that alone.

I stay in aero while taking in nutrient during a long course race.

Ditto. When you start looking at where you can knock off a few minutes here and there in say a 70.3, I figured I was wasting time on the bike leg taking in nutrition (on the hoods) and also slowing down at aid stations to get fluids and then wasting more time topping up my bidons. So now I have one of my bidons that has a water/gel mix and that gets consumed whilst aero.