title: Randomized controlled trial of the Medifast 5 & 1 Plan for weight loss.
abstract: OBJECTIVE
  The Medifast 5 & 1 Plan (MD) is a portion-controlled, nutritionally-balanced, low-fat weight-loss plan. We studied the effects of MD compared with a reduced-energy, food-based diet (FB) on body weight, waist circumference, fat mass and other measures in adults.
  
  
  METHODS
  We conducted a two-parallel-arm, randomized, controlled trial comparing MD to FB over 52 weeks. A total of 120 men and women aged 19-65 years with BMI 35 and 50 kg m(-2) were randomized to MD (n=60) or FB (n=60). Follow-up included a 26-week weight-loss phase and 26-week weight-maintenance phase. Anthropometric, body composition, biochemical and appetite/satiety measures were performed at baseline and at 26 and 52 weeks. An intention-to-treat, linear mixed models analysis was the primary analysis.
  
  
  RESULTS
  Fifty MD subjects (83.3%) and 45 FB subjects (75.0%) completed the study on assigned treatment. At 26 weeks, race-adjusted mean weight loss was 7.5 kg in MD subjects vs 3.8 kg in FB subjects (P=0.0002 for difference); reduction in waist circumference was 5.7 cm in MD vs 3.7 cm in FB (P=0.0064); and fat mass loss was 6.4 kg in MD vs 3.7 kg in FB (P=0.0011). At 52 weeks, the corresponding reductions were 4.7 vs 1.9 kg (P=0.0004); 5.0 vs 3.6 cm (P=0.0082); and 4.1 vs 1.9 kg (P=0.0019) in MD and FB subjects, respectively.
  
  
  CONCLUSIONS
  In obese adults, MD resulted in significantly greater reductions in body weight and fat compared with an FB diet for 1 year after randomization.
authors.affiliation: 1] Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA [2] Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Shikany
authors.forename: A S
authors.initials: AS
authors.lastname: Thomas
authors.forename: T M
authors.initials: TM
authors.lastname: Beasley
authors.forename: C E
authors.initials: CE
authors.lastname: Lewis
authors.forename: D B
authors.initials: DB
authors.lastname: Allison
mesh_terms: D000328:Adult; D000368:Aged; D001835:Body Weight; D018752:Diet, Fat-Restricted; D004038:Diet, Reducing / Q000379:methods*; D002149:Energy Intake; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000453:epidemiology; D010349:Patient Compliance / Q000706:statistics & numerical data; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D015397:Program Evaluation; D012527:Satiation; D016896:Treatment Outcome; D055105:Waist Circumference; D015431:Weight Loss; D061217:Weight Reduction Programs / Q000379:methods*