When looking at protein oriented supplements, there are many different proteins from which to choose. The most readily accessible protein comes from whey based supplements and is useful on days when you're strength training and should be consumed just a short time prior to your workout.
Casein protein on the other hand is a sort of "time-released" protein that takes your body longer to process and utilize, this type of protein is good for endurance athletes to consume prior to bed, to prevent your body from becoming catabolic during your fasting state.
I like myoplex
(by EAS
) for my meal replacements, but I don't know if that has the carb content you're looking for. It is, however, a quick 300 calories, and solid nutrition. When I was distance running, and as a swimmer, I could definitely tell the difference when I started using a MRS for extra meals during the day
(I'm a firm believer in eating at least 6 times daily
). And as far as carbs go, I like to actually know where my carbs come from, so that I can make sure they are by-and-large complex
(whole wheat products, oatmeal, brown rice, etc.
) Increasing your carbs through diet is actually pretty simple.
Finally, a note on "gainers". I don't have much experience with them, but from what I've seen they are marketed for increasing mass in bodybuilders, and I'm not sure that that is what you want as a triathlete
(I am familiar with nutrition but not the sport, so I can't be positive of this
), and furthermore, that sort of carb and protein "loading" isn't, in my opinion, beneficial as a long term lifestyle.
There's my two cents.