The importance of consuming carbs and protein immediately following a workout is arguably recognised as one of the foundational pillars for building muscle as part of a comprehensive resistance exercise program. Taking on calories during this ‘post-workout anabolic window’ has been shown to augment the increased muscle protein synthesis that naturally results from weight training.
However, some new research in a rat in-vitro model system has provided stimulus for rethinking the way we traditionally view post-workout nutrition. In essence, the Italian researchers in this study took a popular cell line of rat muscle cells and compared their behaviour when in a medium deprived of glucose for 2-3 hours vs one with glucose.
The researchers were able to show that following a 2 hour window of glucose deprivation there was a greater stimulation of the cellular cascade (called mTOR signalling) responsible for triggering muscle growth. The study model also revealed another interesting mechanism linked with glucose deprivation; namely that nitric oxide synthesis is stimulated. However, as with the mTOR signalling, this heightened synthesis only lasts for about 2 hours.
Based on the results, the authors hypothesised that a 2 hour window of glucose deprivation following an intense weights workout might serve to help stimulate muscle protein synthesis once glucose is consumed. The findings of this study are not entirely surprising given the recent discoveries in endurance athletes concerning the effects of temporary carbohydrate restriction and favourable metabolic training adaptations. But there still a lot of research to be done before anyone can definitely conclude that such an approach in humans will result in superior muscle gains, when it comes to weight training.
Miniaci MC, et al. Glucose deprivation promotes activation of mTOR signalling pathway and protein synthesis in rat skeletal muscle cells. Pflugers Arch. 2014 Jul 31. [Epub ahead of print].