This fails to adequately reflect the data within

these cited studies. The majority of those studies compared the BGB324 manufacturer co-ingestion of protein and carbohydrate versus carbohydrate alone [11, 12] or versus a different source of protein whilst maintaining similar amounts of carbohydrates [13–15]. Moreover, the last cited study [16] analysed the impact of supplementation timing, not supplement composition. To date there are no clinical studies comparing the impact of the co-ingestion of carbohydrate-protein with just protein supplement on LBM. Interestingly, Wilkinson et al. [14] and Hartman et al. [13] both compared different sources of protein (milk versus soy) which also contained appreciable levels of carbohydrate. Both beverages had similar amounts

of carbohydrate but the glycemic index (GI) differed: soy group contained maltrodextrin while milk group had lactose (as expected). Yet it was the lower GI supplement (milk) which generated the greatest net gain in lean mass [13] and higher fractional synthesis rate [14]. In these studies, at least, GI was not positively associated with muscle gains. To date only three studies [10, 17, 18] have addressed the impact of combined carbohydrate with protein/amino acids versus protein/amino acids alone on acute protein synthesis in young adults. These studies demonstrate that adding carbohydrate to a protein dose that alone is known to maximally stimulate protein synthesis PF-562271 in vivo (20-25 g of high-quality protein rich in leucine) has no additive or synergic effect on muscle Dichloromethane dehalogenase protein synthesis and breakdown. The same result has recently also been demonstrated in older subjects [19]. Converging with those data, the addition of 30 g or 90

g of carbohydrates to 20 g of essential amino acids produces the same effect on protein synthesis and protein breakdown, regardless the great difference in insulinemia in both groups [20]. Insulin seems to only further increase protein synthesis at pharmacological doses [21], which means that it is not achievable by carbohydrate supplementation. There remain valid reasons for the inclusion of carbohydrates into protein supplements that are to be consumed following resistance exercise. These included the maximization of glycogen restoration, especially when the time period between exercise sessions is short [22]. However, based on the available clinical data, there is no evidence that the addition of carbohydrates to a protein supplement will increase, acutely, muscle protein synthesis and, chronically, LBM to a greater extent than protein alone, which is in contrast to the statements of Stark and colleagues [1]. Conclusion and perspectives There is a growing body of literature analysing the impact that co-ingestion of protein-carbohydrate versus carbohydrate alone has on protein synthesis.