Nobody likes spinning their wheels. Time is money after all and when research findings are available that allow you to be smarter and get more out of your training and nutrition efforts you should pay attention.
Hopefully it is common knowledge to you that when you eat holds a great deal of importance and specifically the one hour time period after your resistance training workout is a critical time period where you better feed the body something. And by "something", science tells us it should be around 20 to 25 grams of a high-quality protein. While the post-exercise window has been aggressively researched, other time periods including the time period before and during a bout of resistance exercise have not been investigated as greatly.
The strategy of ingesting key nutrients during a resistance workout was completed by Beelen and colleagues where they had participants complete a brief bout of sprint cycling and resistance exercise while consuming either carbohydrate or a combination of protein and carbohydrate ( Beelen, Koopman et al. 2008 ). To accomplish this task, ten healthy males completed a two hour resistance training workout and every 15 minutes throughout the workout they ingested one of two beverages. Blood and muscle samples were collected and the investigators concluded that the consumption of carbohydrates + protein reduced protein breakdown by 8.4% and improved protein synthesis rates by 33%. Importantly, improvements were made in both protein breakdown and protein synthesis which resulted in net protein balance improving from an overall negative balance (more protein was broken down that what was built = not a good thing) when just carbohydrate was ingested to an overall positive balance when protein was added to the carbohydrate. Most importantly changes in muscle protein synthesis revealed a 49% increase in the carbohydrate + protein group (which also was significantly greater than changes seen when just carbohydrate was consumed).
In closing, the timing of nutrients is important. Multiple studies have indicated that post-exercise ingestion is a primary consideration for athletes wishing to optimize adaptations to their training, but a small group of studies continues to reveal that delivering protein and carbohydrates during resistance exercise is also important.