The Effect of a Low Glycemic Index Diet and Glycemic Load on Body Weight: A Systematic Review and Meta-analyses of Randomized Controlled Trials
Trial Snapshot
- Phase
- Not Applicable
- Sponsor
- University of Toronto
- Enrollment
- 1
- Locations
- 1
- Primary Endpoint
- Body weight analysis
Study Overview
Brief Summary
A low glycemic index (GI) diet has been associated with improved glycemic control in type 2 diabetes patients and a reduced risk of cardiovascular disease (CVD). Low glycemic load (GL) diets have been associated in cohort studies with a reduction in both diabetes incidence and CVD events, especially in overweight individuals, and have been recommended by the Canadian, American and European diabetes associations. Life style modification trials have shown that reducing body weight in overweight or obese individuals improves obesity-related risk factors. The process of a systematic review combines the results from many studies in order to arrive at a pooled weighted average of the true effect. The investigators propose to conduct a systematic review and meta-analysis of the highest quality evidence from randomized controlled trials to assess the effect of low GI/GL diets on body weight change. The results of this synthesis will inform clinical practice guidelines and lead to better health outcomes through informing healthcare providers and patients, stimulating industry innovation, and guiding future research.
Detailed Description
Background: Obesity and overweight have been identified as a risk factor for developing type 2 diabetes, dyslipidemia, hypertension, CVD and certain cancers. Nutrition therapy is the first line treatment for prevention of these health conditions and as a key component during their initial and long term management. Diets based on low GI foods and low GL have been associated with risk reduction of type 2 diabetes and CVD. Current clinical practice guidelines suggest the replacement of high GI foods for low GI foods based on the improvement on glycemic control and CVD risk factors. However, there is no enough evidence to support the association between low GI/GL diets on body weight reduction.
Need for a review: The lack of high quality data in this area to support clinical practice guidelines represents an urgent call for stronger evidence. The use of meta-analyses of controlled feeding trials remains the "Goal Standard" of evidence for nutrition guidelines development.
Objectives: To provide evidence-based guidance for public health policy, health claims, and nutrition guidelines relating to low GI/GL diets, we will conduct a systematic review and meta-analysis of controlled feeding trials to assess the effect of a low GI/GL diet on body weight.
Design: The planning and conduct of the proposed meta-analyses will follow the Cochrane handbook for systematic reviews of interventions. The reporting will follow the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.
Data sources: MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials will be searched using appropriate search terms.
Study Design
- Study Type
- Observational
- Time Perspective
- Prospective
Eligibility Criteria
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Dietary trials in humans
- •Randomized trials
- •Trials more or equals to 12 weeks duration
- •Suitable control group
- •Body weight data
Exclusion Criteria
- •Did not look at glycemic index or glycemic load
- •Co-intervention (i.e. the study is designed in such a way that the effect of glycemic index or glycemic load can not be isolated)
- •Trials looked at glycemic index of specific foods instead of diet as a whole
- •Trials including pregnant or breast feeding women
- •Trials including children
- •Non-human studies
- •Non-randomized trials
- •Trials less than 12 weeks duration
- •Lack of a suitable control group
- •No viable endpoint data
Outcomes
Primary Outcomes
Body weight analysis
Time Frame: >=3-months (up to 2 years is expected)
Body weight change by glycemic index and/or glycemic load exposure
Secondary Outcomes
No secondary outcomes reported
Investigators
John Sievenpiper
Associate Professor
University of Toronto