Hoary I use a similar product, 100% maltodextrin which I get 3kg for less than $20. Gram for gram it is the most 'calorie effective' way of carb loading, and as you say it is essentially tasteless with no fibre so you can basically stick to a normal diet. Other high carb foods will have fat, protein, fibre etc., which IN THIS CONTEXT is undesirable. Calorie efficiency is important if you're 'carbing-up' with some frequency (as I am in months leading up to an Ironman), to prevent unwanted weight gain. Also at least you know the carbs are pretty well pure so go straight where you need them without too much digestion/ processing required.
I use maltodextrin to get up to 550g CHO the day before my long rides (5-7hours); & will use it for two days leading up to Ironman.
I must admit I dont carb load for my three hour runs (& these are usually the morning after a long ride), but it probably wouldn't hurt as i'm always running pretty near on empty. For this reason I generally have a couple of gels over 28-35 k.
I guess the downside to the powder is it eliminates the excuse to go back for seconds / thirds with the intent of 'carb loading'!
Edited by Shankate, 18 April 2012 - 11:32 AM.