Introduction: There is a wealth of evidence from a number of sources that body weight and the proportion of energy from dietary fat are directly related. However, some randomized controlled trials (RCTs) of low-fat diets versus other types of low-energy diets have found no difference in weight loss between treatment groups. Thus, the overall aim of this systematic review and meta-analysis is to assess the effectiveness of low-fat diets as a means of achieving sustained weight loss, using all available randomized clinical trials.Methods: The Cochrane Library, MEDLINE, EMBASE, BIOSIS and bibliographies will be systematically searched for relevant studies. Key journals will be hand searched and experts approached for additional studies.Interim results: The interim meta-analyses suggest that, in overweight and/or obese clients, ad libitum low-fat diets are not more efficacious than other types of low-energy diets in terms of weight loss, and also that, in the same population, low-energy low-fat diets are not more efficacious than low-energy diets which are not low in fat, in terms of weight loss. However, the studies included in the two interim meta-analyses revealed significant heterogeneity which will be examined in greater detail in the final meta-analysis.Conclusion: From our interim analyses of the data, we conclude that low-fat diets are as efficacious as other types of low-energy diets in promoting weight loss in the overweight and obese. Updates and the final report of this systematic review will be published in the Cochrane Library (The Cochrane Library 1997, Issue 4).
Department of Epidemiology, Institute of Child Health, London, UK 2:
Department of Social and Preventive Medicine, University of Queensland, Herston, Australia 3:
Depart- ment of Primary Care and Population Sciences, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2PF, UK.