Study designs of evaluations included in the review
The a-priori inclusion criteria with regards to study design was not reported. Included studies were mainly randomised controlled studies with some sequential studies.
Specific interventions included in the review
The National Cholesterol Education Program's Step I diet (<=30% of total energy as fat, <=10% of energy as saturated fatty acids, and <=300 mg dietary cholesterol/day) and/or Step II diet (<=7% of energy as saturated fatty acids and <=200 mg dietary cholesterol/day). Intervention lasted from 3 weeks to 4 years. Thirteen studies also included an exercise intervention. Nineteen studies included a control group in which individuals maintained their habitual lifestyle and food consumption throughout the study.
Participants included in the review
Free-living individuals who prepared their own food, and were counselled by dieticians or other professionals about implementing low-fat diets.
Outcomes assessed in the review
Changes in plasma total cholesterol (TC), LDL cholesterol, HDL cholesterol, and triacylglycerol. In each study, plasma lipid concentrations after dietary intervention were compared with lipid concentrations in the control group as well as with baseline lipid concentrations.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.