Background: Protein in the diet is commonly ingested from whole foods that contain various macro-and micronutrients. However, the effect of consuming protein within its natural whole-food matrix on postprandial protein metabolism remains understudied in humans. Objective: We aimed to compare the whole-body and muscle protein metabolic responses after the consumption of whole eggs with egg whites during exercise recovery in young men. Design: In crossover trials, 10 resistance-trained men [aged 21 6 1 y; 88 6 3 kg; body fat: 16% 6 1% (means 6 SEMs)] received primed continuous L-[ring- H 3 ]leucine-labeled whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat). Repeated blood and muscle biopsy samples were collected to assess whole-body leucine kinetics, intramuscular signaling, and myofibrillar protein synthesis. Results: Plasma appearance rates of protein-derived leucine were more rapid after the consumption of egg whites than after whole eggs (P = 0.01). Total plasma availability of leucine over the 300-min postprandial period was similar (P = 0.75) between the ingestion of whole eggs (68% 6 1%) and egg whites (66% 6 2%), with no difference in whole-body net leucine balance (P = 0.27). Both whole-egg and egg white conditions increased the phosphorylation of mammalian target of rapamycin complex 1, ribosomal protein S6 kinase 1, and eukaryotic translation initiation factor 4E-binding protein 1 during postexercise recovery (all P , 0.05). However, whole-egg ingestion increased the postexercise myofibrillar protein synthetic response to a greater extent than did the ingestion of egg whites (P = 0.04). Conclusions: We show that the ingestion of whole eggs immediately after resistance exercise resulted in greater stimulation of myofibrillar protein synthesis than did the ingestion of egg whites, despite being matched for protein content in young men. Our data indicate that the ingestion of nutrient-and protein-dense foods differentially stimulates muscle anabolism compared with protein-dense foods. This trial was registered at clinicaltrials.gov as NCT03117127.

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The effect of nutrient‐dense food ingestion immediately after resistance exercise as a nutritional strategy to promote muscle anabolism has not been clearly established. Given that a coordinated anabolic response is necessary for the regulation of muscle protein synthesis with exercise and protein ingestion, our aim was to determine whether egg whites or whole eggs ingestion influenced post‐exercise mechanistic target of rapamycin complex 1 (mTORC1) and mitogen‐activated protein kinase (MAPK) signaling phosphorylation in human skeletal muscle. In crossover trials, 10 healthy resistance‐trained men (21±1 y; 88±3 kg; bodyfat: 16±1%; means±SD) completed lower body resistance exercise (4 sets of 10 repetitions at 80% of 10‐RM for both leg press and leg extensions) before ingesting whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat) in scrambled form. Muscle biopsies were obtained before exercise and at 2 and 5H after protein ingestion to assess the phosphorylation of candidate anabolic signaling molecules by Western blotting. The phosphorylation of mTORser2448 increased ~34% above fasted at 5H following whole egg and egg white consumption (time effect; P<0.01) with no difference between conditions (P>0.66). Downstream of mTORC1, 4E‐BP1Thr37/46 was elevated above fasted at 2H (~22–44%; P<0.01) and was sustained above fasted at 5H (P<0.01) with no differences between conditions (P>0.14). There was no effect of food ingestion on S6K1Thr389 and eEF2Thr56. The phosphorylation of the MAPK ERK1/2Thr202/Tyr204 was similarly suppressed at 2 and 5H following feeding for the whole egg and egg white conditions (~430–780%; P<0.001). Ingestion of isonitrogenous amounts of whole egg and egg white similarly stimulates anabolic signaling in young trained males. These findings would suggest a similar increase in mRNA translation initiation during recovery from resistance exercise in healthy young men. Identification of the intracellular localization of mTORC1 and its colocalization with positive (e.g. Rheb) and negative (e.g. TSC2) regulators via immunofluorescence is ongoing.

The majority of protein consumed in the diet is obtained from whole food sources that contain a mixture of macro‐ and micronutrients. Whereas the majority of research investigated the effect of isolated protein sources on protein metabolism, our aim was to assess the muscle anabolic potential of consuming a complete protein within its naturally occurring, nutrient dense food matrix during recovery from resistance exercise in young men. In crossover trials, 10 healthy resistance‐trained men (21±1 y; 88±3 kg; bodyfat: 16±1%) received primed continuous L‐[ring‐2H5]phenylalanine and L‐[1‐13C]leucine infusions. Repeated blood and muscle biopsies were collected before and after a single bout of resistance exercise (4 sets of 10 repetitions at 80% of 10‐RM for both leg press and leg extensions). Immediately after resistance exercise, participants ingested intrinsically L‐[5,5,5‐2H3]leucine labeled whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat) cooked in scrambled form. Exogenous leucine appearance rates increased (P<0.001) after protein ingestion with peak values of 513±57 nmol leucine·kg−1·min−1 occurring at 75 min after egg white ingestion compared with 496±38 nmol leucine·kg−1·min−1 at 120 min after whole egg ingestion. The total amount of protein derived leucine that became available in circulation over the 300 min postprandial period was similar (P=0.53) between whole egg (75±2.3%) and egg white ingestion (77±1.7%). Whole egg ingestion supported greater post‐exercise myofibrillar protein synthesis rates when compared to egg white ingestion (0.034%/h and 0.024%/h respectively; P=0.02). We conclude that whole egg ingestion stimulates the muscle protein synthetic response more effectively than the consumption of isonitrogenous amounts of egg whites during recovery from resistance exercise in healthy young men. This effect is not attributed to divergent postprandial protein‐derived amino acid availability, suggesting that some intrinsic factor within whole eggs and/or the divergent macronutrient profile may have modified the anabolic potential of this complete protein.Support or Funding InformationVision 20/20 Grant, Division of Nutritional Sciences, University of Illinois, Urbana‐Champaign

The consumption of isolated proteins and/or crystalline amino acids enhances the anabolic effect of resistance exercise during recovery. However, the effect of consuming dietary amino acids within their natural nutrient‐dense food matrix to support whole body recovery from resistance exercise has received little attention. Therefore, we determined the effects of whole egg versus egg white ingestion on whole body leucine metabolism in resistance‐trained young males. In crossover trials, six resistance‐trained men (21±1 y; 90±5 kg) received primed constant L‐[1‐13C]leucine infusions with repeated breath and blood samples collected before and 5 h after resistance exercise to determine whole body leucine endogenous rate of appearance (Endo Ra; estimate of protein breakdown), oxidation (OX), non‐oxidative leucine disposal (NOLD; estimate of protein synthesis) and net balance (NB). Immediately after resistance exercise, participants ingested intrinsically L‐[5,5,5‐2H3]leucine labeled whole eggs (18 g protein, 17 g fat; 1.6 g leucine) or egg whites (18 g protein, 0 g fat; 1.6 g leucine) in scrambled form. Endo Ra declined (P<0.001) from fasting values after whole egg (15±1%) and egg white (22±3%) ingestion with no difference between conditions (P=0.14). Similarly, OX decreased over the 5 h period after whole egg and egg white ingestion (P<0.001) with no differences between conditions (P=0.62). NOLD tended to increase (P=0.08) after ingestion of whole egg (10±2%) and egg white (6±3%) with no differences between conditions (P=0.17). As such, NB was negative before exercise but improved similarly (P<0.001) after whole egg (97±6%) and egg white (102±9%) ingestion (P=0.36). In summary, there was a similar increase in whole body NB after the ingestion of whole eggs and egg whites, which was primarily modulated by changes in postprandial whole body protein breakdown rather than protein synthesis during post‐exercise recovery. These data demonstrate that consuming high‐quality protein within a complete food matrix is an effective nutritional strategy to improve whole body net protein balance after resistance exercise in trained young men.Support or Funding InformationVision 20/20 Grant, Division of Nutritional Sciences, University of Illinois at Urbana ‐ Champaign