A randomised controlled trial of 4 different commercial weight loss programmes in the UK in obese adults: body composition changes over 6 months.

Author: Truby H, Millward D, Morgan L, Fox K, Livingstone MB, DeLooy A, Macdonald I

Author affiliation: University of Surrey, Guildford, UK.

Publication date & source: 2004.08, Asia Pac J Clin Nutr., 13(Suppl):S146.

The growing rise in obesity and the search for solutions has led to an increase in the number of commercial weight loss programmes with differing approaches. However there is limited information available by which their efficacy has been compared in controlled studies. The 4 diets tested in this study were chosen to represent different approaches. These were the Slim-Fast Plan (a meal replacement approach), WeightWatchers Pure Points Programme (an energy controlled diet with weekly group meetings), Dr Atkins' New Diet Revolution (a self-monitored low carbohydrate eating plan) and Rosemary Conley's "Eat Yourself Slim" Diet & Fitness Plan (a low fat diet and a weekly group exercise class). The primary outcome measure was percentage of fat loss over 24 weeks, measured using dual energy x-ray absorptio-metry. A total of 293 healthy people entered the randomisation process: 79 (27%) men and 214 (73%) women with an average body mass index of 31.7 kg/m2 (range 27-38) and average age of 40.3 years. The results indicated that all the diets tested were effective and did produce significant weight and body fat loss compared to controls. On average men lost 9.12 kg (23% of initial body fat) and women 5.2 kg (16% of initial body fat). However, there was considerable variation in body fat loss within each diet group. This led to the average differences between the diets being quite small and not significant. No attempt was made to standardise energy intake across the groups and therefore the effects seen are due to the subjects own interpretation and compliance with the diet plan they were given. This study demonstrates that loss of body fat is possible using a variety of commercially available strategies, including the Atkins diet. However, the range of fat loss demonstrates that some subjects actually lost very little fat and some a great deal. This indicates that not every approach will suit everyone equally. If commercial weight loss programmes are to be used effectively more information is needed to direct individuals to the best strategy to suit their needs.