Authors' objectives:

This review aims to assess the available evidence on diet programs for weight loss in adults.

Authors' recommendations: With regard to diet programs for weight loss in adults, the ICSI Technology Assessment Committee finds: The critical component for weight loss is energy balance, i.e., caloric expenditure must exceed caloric intake. It is difficult to evaluate the outcomes of the existing studies. Many of the studies had a large percentage of patients drop out; had short follow-up periods; included dietary, behavioral, and/or activity components; and did not adequately report compliance with the diet program. Many of the diet programs combine multiple elements (reduced calorie, reduced fat, reduced energy density, etc.) making it impossible to identify a critical component. Overall, the diet programs that have been studied are safe for short term use with the possible exception of side-effects associated with very-low-calorie diets. In general, there are insufficient long-term data to allow conclusions to be reached about long-term safety. Overall, with the exception of short-term outcomes following very-low-calorie diet programs, only a small percentage of subjects participating in any of the diet programs studied in this report achieved weight losses of 10% or more of initial body weight. Evidence, to date, does not support any one specific weight loss diet program being more effective than others reviewed in providing lasting, clinically significant weight loss. However, there may be other reasons to choose one diet plan over another including consistency with other dietary guidelines that are known to improve health, personal preference, and individual patient characteristics. Low carbohydrate diets have been found to produce more rapid short-term (3 to 6 months) weight loss than conventional low calorie diets. Long-term safety and effectiveness have not been adequately studied. (Conclusion Grade II) Low energy diets result in moderate weight loss for individuals who complete programs ranging from 3 to 18 months (independent of fat content and whether energy deficit is individualized or not). (Conclusion Grade II) Low fat diets lead to modest weight loss at 3 to 6 months. Greater weight loss was observed in patients with greater baseline weights. (Conclusion Grade II) Very-low-calorie diets produce rapid weight loss of a large amount of weight at 12 to 17 weeks but the weight loss is typically not maintained at 1 to 2 years in the absence of ongoing dietary and behavioral support. Diet programs of less than 800 kcal/day offer little benefit in terms of weight loss. (Conclusion Grade II) Meal replacement diets are associated with significant weight loss maintained for up to 2 years among completers of the program. (Conclusion Grade II)

Authors' methods: Review

Project Status: Completed

URL for project: http://www.icsi.org/knowledge/detail.asp?catID=107&itemID=1742

Year Published: 2004

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Institute for Clinical Systems Improvement

Contact Address: 8009 34th Avenue South, Suite 1200, Bloomington, MN, USA. Tel: +1 952 814 7060; Fax: +1 952 858 9675

Contact Name: icsi.info@icsi.org

Contact Email: icsi.info@icsi.org

Copyright: Institute for Clinical Systems Improvement (ICSI)