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Post‐exercise meal timing alleviates decreased protein efficiency for skeletal muscle growth in rats fed high‐protein diet
Author(s) -
Kondo Emi,
Inoue Nagisa,
Okada Sachiko,
Yaji Keiko,
Hirota Ayumi,
Okamura Koji
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.869.4
Subject(s) - endocrinology , skeletal muscle , medicine , meal , biceps , chemistry , anatomy
To examine whether the upper limit of dietary protein for skeletal muscle growth would be increased if protein is ingested in proper timing in relation to exercise, rats fed at 8:00–10:00 and 20:00–22:00 were exercised with a climbing cage (Kondo et al. EB2007), 3 times a week for 8 weeks. The exercise started at 14:00 (14E) or 18:00 (18E). The proximate meal located 4h after exercise for 14E and immediately after exercise for 18E. The rats were fed either a normal protein diet (N, protein 18%) or a high protein diet (H, protein 35%), and each diet group was divided to a sedentary (S), 14E or 18E group. The rats were pair‐weighted. Nitrogen balance measured in the 7 th week of the study was more positive in the H‐fed groups than the N‐fed groups without differences regarding both meal timing and exercise. After 8 weeks, the skeletal muscle mass (sum of the gastrocnemius, soleus, plantaris, Extensor digitorum longus, tibialis anterior, flexor hallucis longus and biceps brachii) was lower in the H‐fed rats than the N‐fed rats, and it was lower in 14EH (8.29g (SD 0.63)) than both SH (8.99 (0.38)) and 18EH (9.22 (0.53)) while SH and 18EH were comparable. The difference in the skeletal muscle mass between H‐fed and N‐fed was less in 18E than both S and 14E (SN > SH (−3.1%), 14EN > 14EH (−7.7%), 18EN = 18EH (−0.8%)). These results suggest that ingesting a meal in proper timing after exercise may not increase the upper limit of dietary protein for skeletal muscle growth, while it appears to alleviate the decreased efficiency of skeletal muscle growth in H‐fed animals.