title: Whey protein and essential amino acids promote the reduction of adipose tissue and increased muscle protein synthesis during caloric restriction-induced weight loss in elderly, obese individuals.
abstract: BACKGROUND
  Excess adipose tissue and sarcopenia presents a multifaceted clinical challenge that promotes morbidity and mortality in the obese, elderly population. Unfortunately, the mortality risks of muscle loss may outweigh the potential benefits of weight loss in the elderly. We have previously demonstrated the effectiveness of whey protein and essential amino acids towards the preservation of lean tissue, even under the conditions of strict bedrest in the elderly.
  
  
  METHODS
  In the context of caloric restriction-based weight loss, we hypothesized that a similar formulation given as a meal replacement (EAAMR) would foster the retention of lean tissue through an increase in the skeletal muscle fractional synthesis rate (FSR). We also proposed that EAAMR would promote the preferential loss of adipose tissue through the increased energy cost of skeletal muscle FSR. We recruited and randomized 12 elderly individuals to an 8 week, caloric restriction diet utilizing equivalent caloric meal replacements (800 kcal/day): 1) EAAMR or a 2) competitive meal replacement (CMR) in conjunction with 400 kcal of solid food that totaled 1200 kcal/day designed to induce 7% weight loss. Combined with weekly measurements of total body weight and body composition, we also measured the acute change in the skeletal muscle FSR to EAAMR and CMR.
  
  
  RESULTS
  By design, both groups lost ~7% of total body weight. While EAAMR did not promote a significant preservation of lean tissue, the reduction in adipose tissue was greater in EAAMR compared to CMR. Interestingly, these results corresponded to an increase in the acute skeletal muscle protein FSR.
  
  
  CONCLUSIONS
  The provision of EAAMR during caloric restriction-induced weight loss promotes the preferential reduction of adipose tissue and the modest loss of lean tissue in the elderly population.
authors.affiliation: Center for Translational Research in Aging and Longevity, Little Rock, AR, USA. cokerrobert@uams.edu
authors.forename: Robert H
authors.initials: RH
authors.lastname: Coker
authors.forename: Sharon
authors.initials: S
authors.lastname: Miller
authors.forename: Scott
authors.initials: S
authors.lastname: Schutzler
authors.forename: Nicolaas
authors.initials: N
authors.lastname: Deutz
authors.forename: Robert R
authors.initials: RR
authors.lastname: Wolfe
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects*; D000368:Aged; D000369:Aged, 80 and over; D000601:Amino Acids, Essential / Q000008:administration & dosage*; D001823:Body Composition; D001835:Body Weight; D031204:Caloric Restriction; D002149:Energy Intake; D005260:Female; D006801:Humans; D008297:Male; D008894:Milk Proteins / Q000008:administration & dosage*; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism; D009765:Obesity / Q000178:diet therapy*; D015431:Weight Loss / Q000187:drug effects*; D000067816:Whey Proteins
chemical_list: D000601:Amino Acids, Essential; D008894:Milk Proteins; D009124:Muscle Proteins; D000067816:Whey Proteins