Whey protein has a digestion time frame of around 30 mins, Hydrolyzed whey peptides are digested even faster. Waxy maize starch carbohydrates make it into your intestinal track within minutes. So it is easily achievable to deliver nutrition to your body within that time frame. Normal food may take over 2 hours to digest, but supplements allow for us to take full advantage of the IGF bolus that is released during heavy weight training sessions, This is where they get the 90 minute window where our muscles are absorbing larger amounts of nutrients. also I know you are somewhat catabolic already during training, but doing an additional 45 minutes of cardio without some source of nutrition will just further limit possible protein synthesis and extend the catabolic environment. other than artificial hormones, the best way to stimulate protein synthesis is to raise your blood amino acid levels far above normal levels. The longer you wait, the more time your missing out on raising muscular protein synthesis.
Not saying everything I said is 100% correct but thats just what I learned over the years of supplementation and weigh training. I would like to hear other peoples opinion on this issue also