Sleep promotes repair and restoration.  Peter Res from Maastricht University Medical Center, and colleagues, found that consuming 20 grams of casein protein 30 minutes before bedtime promoted protein synthesis more than a placebo (fake protein).  The test subjects performed a vigorous bout of weight training at 8:00 p.m.  The supplement increased the rate of protein synthesis by 21 percent and boosted the overall protein balanced by more than 100 percent.  The researchers used sophisticated isotopic labeling methods to accurately measure the rate of protein synthesis.

This was an important study for bodybuilders.  After weight training, consuming a protein supplement shortly before bed will promote recovery and maximize protein synthesis.  (Medicine Science Sports Exercise,  44:  1560-1569, 2012)