Protein to Maximize Whole-Body Anabolism in Resistance-trained Females after Exercise

Med Sci Sports Exerc. 2019 Apr;51(4):798-804. doi: 10.1249/MSS.0000000000001832.


Introduction: Current athlete-specific protein recommendations are based almost exclusively on research in males.

Purpose: Using the minimally invasive indicator amino acid oxidation technique, we determined the daily protein intake that maximizes whole-body protein synthesis (PS) and net protein balance (NB) after exercise in strength-trained females.

Methods: Eight resistance-trained females (23 ± 3.5 yr, 67.0 ± 7.7 kg, 163.3 ± 3.7 cm, 24.4% ± 6.9% body fat; mean ± SD) completed a 2-d controlled diet during the luteal phase before performing an acute bout of whole-body resistance exercise. During recovery, participants consumed eight hourly meals providing a randomized test protein intake (0.2-2.9 g·kg·d) as crystalline amino acids modeled after egg protein, with constant phenylalanine (30.5 mg·kg·d) and excess tyrosine (40.0 mg·kg·d) intakes. Steady-state whole-body phenylalanine rate of appearance (Ra), oxidation (Ox; the reciprocal of PS), and NB (PS - Ra) were determined from oral [C] phenylalanine ingestion. Total protein oxidation was estimated from the urinary urea-creatinine ratio (U/Cr).

Results: A mixed model biphase linear regression revealed a break point (i.e., estimated average requirement) of 1.49 ± 0.44 g·kg·d (mean ± 95% confidence interval) in Ox (r = 0.64) and 1.53 ± 0.32 g·kg·d in NB (r = 0.65), indicating a saturation in whole-body anabolism. U/Cr increased linearly with protein intake (r = 0.56, P < 0.01).

Conclusions: Findings from this investigation indicate that the safe protein intake (upper 95% confidence interval) to maximize anabolism and minimize protein oxidation for strength-trained females during the early ~8-h postexercise recovery period is at the upper end of the recommendations of the American College of Sports Medicine for athletes (i.e., 1.2-2.0 g·kg·d).

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Creatinine / urine
  • Dietary Proteins / administration & dosage*
  • Energy Metabolism
  • Female
  • Humans
  • Muscle Proteins / biosynthesis*
  • Muscle, Skeletal / metabolism*
  • Nutritional Requirements
  • Oxidation-Reduction
  • Phenylalanine / administration & dosage
  • Phenylalanine / metabolism
  • Prospective Studies
  • Resistance Training*
  • Tyrosine / administration & dosage
  • Tyrosine / metabolism
  • Urea / urine
  • Young Adult


  • Dietary Proteins
  • Muscle Proteins
  • Tyrosine
  • Phenylalanine
  • Urea
  • Creatinine