THE DASH-SODIUM TRIAL - FNCE

Weight Change (Lbs.)11/19/2010Superiority of High-Unsaturated Fat,Mediterranean-style diet for weight lossBaseline 6 Months 12 180 0-5-10-15-14-13MediterraneanLow Fat-11-6-12 -11Weight Gain in the Dropouts:Mediterranean and Low-FatGroups Combined• Dropouts had a net gain in weight of9 pounds from the starting weightafter 18 months.• Those staying in the program lost 11pounds.McManus, Antinoro, Sacks. Int J Obesity 2001;25: 1503-11Interpretation of Comparative WeightLoss Trials• Divergent results among studies• Each diet type showed superiority overother types in certain trials.• No obvious pattern of results favoring aspecific fat, carb or protein content forweight loss.• Superiority of a diet type in the first 6months often not sustained by 1 to 2 y.Limitations of Some ComparativeTrials of Diet Types and Weight Loss• Large percentage of dropouts, up to 50%• Novelty of one of the diets, mediaattention, and its marketing may haveaffected expectations of success.• Equipoise may not have been achieved;researchers may have subtly favored adiet.PoundsLost Trial: Design• 811 overweight or obese people in Boston(Harvard School of Public Health) and BatonRouge (Pennington Biomedical ResearchCenter, LSU System)• Randomization among 4 diet types• Duration of treatment 2 years• Primary Outcome: Body weight, changefrom baseline to 2 years.• Secondary Outcome: Waist Circumference• Primary Analysis: Intention-to-treat withimputation of missing outcome data.• Secondary Analysis: Completers (80%)PoundsLost Trial: DietsThese diets with target nutrient levels:1. Low-fat (20%), average protein (15%), highestcarbohydrate (65%)2. Low-fat (20%), high protein (25%),carbohydrate (55%)3. High fat (40%), average protein (15%),carbohydrate (45%)4. High fat (40%), high protein (25%), lowestcarbohydrate (35%)Similar foods used for all diets but in differentproportions. All dietary approaches adhered tohealthful guidelines to prevent cardiovascular disease.3