With an iron taint, I'm surprised you're worried about a mere smell in the shower.

Likely a picture of you overall dietary mix if it is happening regularly and a morning intake will not meet demand. This happens to me when I am watching intake from a total caloric perspective with the goal of trying to cut or maintain weight at worse. The issue is exacerbated with lower carb diets (diets being used here in the traditional sense).

Simplified Ex:

40/30/30 diet with daily intake at 3000 calories for a even (in/out) calorie/day....Carbs (1200 calories)

Rest assured (pun intended) when you go to bed you are already sufficiently lean on carb stores and come morning a little more leaner.

What works for me is as total calories get close to or fall short of daily burn I need to richen up the mix, i.e. more carbs in the ratio. This can be done throughout the day of slightly loaded in the evening if next day's morning workout is higher intensity. A 60% mix on carbs usually does it with the usual caveats of intensity, overall volumes, timing of intake...

When I do hard trainer intervals in the morning I generally take in a gu mid-workout as well. FWIW, once I get into a peak training cycle, running a caloric deficit or leaning the mix ends up in ketosis. Take this as a cool science experiment on yourself. Disclaimer: if you are diabetic seek a professional consult.

Of course this time of year my diet is sH$% so no need to change anything as carbs are plentiful:)

I'll try a Gu tomorrow morning. It seems that between my oatmeal, juice, and Gatorade, I should be getting enough carbs before the workout. It might be that they aren't getting to the muscles in time to do any good, though I'd think the juice and Gatorade would.

What is your body composition like? I wonder if a body carrying a lot of muscle decides that the muscle has to go when you are doing things that don't like all that muscle (e.g. distance running). I had that ammonia sweat smell often a number of years ago and it did not seem to be related to diet. I was, however, carrying about 30lbs of muscle mass that has since gone away.