If you do not eat after your workout, you remain in a negative protein balance. Prior work has clearly
shown that consuming protein or carbohydrate after a workout has beneficial effects on protein balance. Further work
has shown that there may be benefits of consuming protein and carbohydrates before your workout on protein balance.
However, no study to date had examined the effects of consuming timed protein and carbohydrate supplements on
adaptations to chronic training. In a recent study published in Metabolism, researchers randomized young untrained
men into either a protein or carbohydrate supplementation group. Both groups performed a resistance training
program for 14 weeks. The protein group consumed 25 g of protein (primarily whey) and the carbohydrate group
an equal amount of maltodextrin immediately before and immediately after each workout as well as non-training
days. A muscle biopsy was performed before and after 14 wks of training to determine the extent of muscle fiber
hypertrophy. Both groups increased performance but only the protein group demonstrated significant hypertrophy
in both the slow twitch (18%) and fast twitch (26%) muscle fibers. This study shows 'real world' results and
brings meaning to the acute studies that showed stimulation of protein synthesis with timed protein ingestion
by showing that repeated intake of 25 g of whey protein before and after training has an anabolic effect on
muscle mass over carbohydrate supplementation.
Andersen LL, Tufekovic G, Zebis MK, Crameri RM, Verlaan G, Kjaer M, Suetta C, Magnusson P, Aagaard P. The effect of resistance training combined with timed ingestion of protein on muscle fiber size and muscle strength. Metabolism. 2005 Feb;54(2):151-156.