title: Exploration of the protein requirement during weight loss in obese older adults.
abstract: BACKGROUND
  Currently there is no consensus on protein requirements for obese older adults during weight loss. Here we explore the potential use of a new method for assessment of protein requirements based on changes in appendicular muscle mass during weight loss.
  
  
  METHODS
  60 obese older adults were subjected to 13 wk weight loss program, including hypocaloric diet and resistance training. Assessment of appendicular muscle mass was performed by DXA at baseline and after 13 wk challenge period, and the difference calculated as muscle mass change. Protein intake (g/kg body weight and g/kg fat free mass (FFM)) at 13wks was used as marker of protein intake during 13 wk period. 30 subjects received 10 times weekly 20 g protein supplement throughout the 13 week hypocaloric phase which is included in the calculation of total protein intake. Receiver operating characteristic (ROC) curve analysis was used to explore the optimal cutoff point for protein intake (g/kg) versus increase in appendicular muscle mass of more than 250 g over 13 wks (y/n). Subsequently, logistic regression analysis was performed for protein intake cutoff and muscle mass accretion, adjusted for sex, age, baseline BMI, and training compliance.
  
  
  RESULTS
  ROC curve analysis provided a protein intake level per day of 1.2 g/kg bw and 1.9 g/kg FFM as cutoff point. Presence of muscle mass accretion during 13 wk challenge period was significantly higher with protein intake higher than 1.2 g/kg bw (OR 5.4, 95%CI 1.4-20.6, p = 0.013) or higher than 1.9 g/kg FFM (OR 8.1, 95%CI 2.1-31.9, p = 0.003). Subjects with a protein intake higher than 1.2 g/kg had significantly more often muscle mass accretion, compared to subjects with less protein intake (10/14 (72%) vs 15/46 (33%), p = 0.010). For 1.9 g/kg FFM this was 70% vs 28% (p = 0.002).
  
  
  CONCLUSIONS
  This exploratory study provided a level of at least 1.2 g/kg body weight or 1.9 g/kg fat free mass as optimal daily protein intake for obese older adults under these challenged conditions of weight loss, based on muscle mass accretion during the challenge.
  
  
  BACKGROUND
  Dutch Trial Register under number NTR2751.
authors: Department of Nutrition and Dietetics, School of Sports and Nutrition, Amsterdam University of Applied Sciences, Amsterdam, The Netherlands; Department of Nutrition and Dietetics, Internal Medicine, VU University Medical Center Amsterdam, Amsterdam, The Netherlands; EMGO+ Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: p.j.m.weijs@hva.nl.
authors: Peter J M
authors: PJM
authors: Weijs
authors: Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 806, Little Rock, AR 72205, USA. Electronic address: rwolfe2@UAMS.edu.
authors: Robert R
authors: RR
authors: Wolfe
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D004038:Diet, Reducing; D004044:Dietary Proteins / Q000008:administration & dosage*; D004311:Double-Blind Method; D002149:Energy Intake; D005260:Female; D018737:Hand Strength; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism; D009751:Nutritional Requirements; D009765:Obesity / Q000178:diet therapy*; D055070:Resistance Training; D055105:Waist Circumference; D015431:Weight Loss
chemical_list: D004044:Dietary Proteins
keywords: Elderly; Obesity; Protein needs; Treatment; Weight loss