Skeletal muscle mass is maintained by the balance between muscle protein synthesis and breakdown rates such that overall muscle net protein balance (NPB) remains essentially unchanged over the course of the day. A prolonged negative NPB will result in a loss of skeletal muscle proteins. Ageing or prolonged periods of disuse (due to illness or a sedentary lifestyle) exacerbate the loss of skeletal muscle mass. It has been speculated that the capacity of skeletal muscle tissue to recover from prolonged periods of muscle unloading is reduced with advancing age. Therefore, a greater understanding of the proposed mechanisms underpinning the unloading induced atrophy, and the eventual incomplete recovery that generally follows, will certainly contribute to the development of more effective nutritional or lifestyle strategies to attenuate muscle mass loss and support healthy ageing. The lack of skeletal muscle recovery following unloading in the elderly may be explained by an observed phenomenon commonly coined ‘anabolic resistance’ of muscle protein synthesis rates. Specifically, frequent periods of disuse, simplified as ‘inactive muscle’, will desensitize skeletal muscle to hyperaminoacidaemia and ultimately lead to a reduced muscle protein synthetic response when compared with the response of active skeletal muscle to the same stimuli. There is no general consensus on whether anabolic resistance of muscle protein synthesis rates is truly an inherent intrinsic characteristic of ageing muscle or a self-induced product of a sedentary lifestyle. Hitherto, the role of muscle protein breakdown in unloading-induced disturbances of protein metabolism has not been studied profoundly. However, it is assumed that any change in muscle protein breakdown rates during unloading is an adaptive response to changes in muscle protein synthesis rates. Of course, more in vivo human research is necessary to understand the quantitative role of muscle protein breakdown during periods of unloading. Thus, due to the sparse knowledge regarding muscle protein breakdown rates in unloading-mediated muscle atrophy, contemporary interventions generally focus on nutritional strategies known to stimulate muscle protein synthesis rates. Recent work from our lab has revealed that the type of protein consumed can have a fundamental impact on postprandial muscle protein synthesis rates (Pennings et al. 2011). Specifically, we found that ingestion of a meal-like amount of whey protein (20 g) is more effective at stimulating postprandial muscle protein synthesis rates than ingestion of an isonitrogenous amount of casein hydrolysate or micellar casein (Pennings et al. 2011). We speculated that the superiority of whey protein for the stimulation of postprandial muscle protein synthesis rates is probably attributable to both its speed of digestion/absorption and its higher leucine content. Thus, meal-induced leucinaemia appears to be a primary driver of the anabolic response. Interestingly, Glover et al. (2008) investigated whether increasing the blood amino acid availability can overcome the anabolic resistance of muscle protein synthesis rates to amino acid provision induced by immobilization. It was observed across a wide range of amino acid concentrations that the immobilized limb revealed a blunted muscle protein synthetic response when compared to the non-immobilized limb. Notably, even a high-dose amino acid infusion could not overcome the anabolic resistance of muscle protein synthesis rates imposed by unloading. These data also suggest that eating large amounts of protein may be a fruitless nutritional strategy to offset muscle mass loss during unloading. Despite these results in young adults (Glover et al. 2008), it provides perspective for more research into the phenomenon of immobilization-induced anabolic resistance among the elderly. As a matter of fact, the effects of different anabolic stimuli, such as intact proteins or free dietary amino acid supplementation, after prolonged periods of unloading during ageing remain largely unknown. Recently, an article published in The Journal of Physiology by Magne et al. (2012) provided new insights into nutritional strategies that may help recover muscle mass after a prolonged period of unloading. The authors used a rodent (male Wister rats aged 22–24 months) unilateral hind-limb cast immobilization model. After 10, 20, 30 and 40 days of recovery from an 8 day immobilisation period, muscle protein synthesis rates, markers of proteolysis and intramuscular anabolic signalling protein phosphorylation were measured. The authors observed that ∼20% of the gastrocnemius muscle mass was lost following immobilisation. Muscle protein synthesis rates were depressed in the postprandial state after prolonged mechanical unloading in the elderly rats and did not normalize during reloading. In addition, the authors report that leucine supplementation was not as effective as whey or high-protein diets in maximizing skeletal muscle mass after 40 days of recovery. This is an interesting finding since leucine is presumed to be highly anabolic toward the stimulation of muscle protein synthesis rates and often used as a pharmaconutrient to improve muscle recovery after prolonged periods of unloading. However, it has recently been demonstrated that simply supplementating the diet with free dietary leucine (7.5 g d−1) is not an effective strategy to increase muscle mass or strength, in healthy elderly men consuming the recommended dietary allowance for protein (Verhoeven et al. 2009). With respect to the animal in vivo measurements of muscle protein synthesis by Magne et al. (2012), the positive leucine-induced effect on the stimulation of muscle protein synthesis rates failed to translate into muscle growth. Moreover, other factors involved in stimulating muscle protein synthesis rates were also altered in favour of muscle protein synthesis, despite the lack of long-term benefits. For example, free leucine supplementation increased the amount of phosphorylation of S6 and 4EBP1 proteins and at the same time generated a decrease in chymotrypsin- and trypsin-like activities of the 26S proteasome associated with a P-FOXO3a/FOXO3a ratio in favour of antiproteolytic processes. However, when the duration of muscle protein synthesis increment is inadequate to generate a significant muscle protein accretion, the effect on muscle mass is negligible, which is in accordance with the authors’ conclusion. Unlike free leucine supplementation, whey and high-protein diets resulted in a ∼60% regain of the amount of muscle lost with immobilization. This could be explained by the larger increases in muscle protein synthesis rates after the whey and high-protein diets. Despite the positive effects of free leucine supplementation on muscle protein synthesis rates, it appears that intact proteins are essential to gain muscle mass. Notwithstanding, proteins enriched with leucine might be applicable to accelerate muscle regain or prevent muscle loss. Magne et al. (2012) are to be praised for studying the role of leucine and even more for underpinning the importance of intact proteins such as whey or consumption of higher protein diets in the recovery of muscle mass during or after a period of muscle disuse. The next step is to translate the authors’ work to a human model. Therefore, we need immobilization trials with elderly people to investigate whether the animal findings are similar to that of in vivo human work. Notable is that Drummond et al. (2012) examined the effect of 7 days of bed rest and amino acid supplementation on muscle protein synthesis rates in humans. As in previous trials, Drummond et al. (2012) showed that 7 days of bed rest blunted the essential amino acid-induced increase in muscle protein synthesis rates. In addition, the workers studied different types of amino acid transporters, to decipher whether a reduced amino acid-transporter response was partly responsible for the desensitization to amino acidaemia of muscle during disuse. To stimulate mTORC1 signalling exogenous amino acids first have to enter the muscle cell via active transport. Interestingly, both amino acid transporters, LAT1 and SNAT2, are associated with mTORC1 activation and muscle protein synthesis rates. Indeed, in addition to the impaired response in muscle protein synthesis following an amino acid stimulation the authors found a decrease in amino acid-transporter content, thus providing some clue as to how anabolic resistance of muscle proteins synthesis rates to amino acids manifests during unloading. Taken together, the work from Magne et al. (2012) and other referenced authors contributes to the development of nutritional strategies to recover muscle mass after periods of muscle disuse (e.g. injury or illness) in the elderly. Importantly, the authors’ findings point to a thesis that high-quality proteins, such as whey, that are easily digested (and already high in leucine) are superior to create an anabolic environment, especially after periods of disuse. This message is one that those supplementing their diet with free dietary leucine with a wish of building bigger muscles might not want to hear! In conclusion, the addition of free leucine next to our habitual diet is not the answer to prevent muscle loss or accelerate muscle regain. More work is needed to explore the anabolic properties of our nutrition in general, with the functional properties of different proteins in particular.