Dietary interventions and quality of life: a systematic review of the literature.

OBJECTIVE: To systematically review the literature to examine whether there has been adequate assessment of the effects of dietary intervention on quality of life (QOL) independent of weight loss, assess which instruments are being used to measure nutrition-related QOL, identify gaps in the literature, and suggest future directions. DESIGN: Systematic review guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement. RESULTS: A total of 24 studies were eligible for inclusion. The Short Form-36 Health Survey was the most widely used instrument to assess QOL. Other disease-specific instruments were used. Several different dietary approaches (eg, low carbohydrate, low calorie, low fat, combinations) were recommended. Across studies, QOL generally improved after participating in behavioral weight loss interventions, but findings revealed a lack of evidence to definitively determine whether reported changes in QOL were a result of weight loss or independent of it. CONCLUSIONS AND IMPLICATIONS: It is important to consider how making broad dietary recommendations for all individuals might affect overall QOL in both positive and negative directions when considering factors other than weight loss and health improvement. If dietary interventions are adversely affecting QOL in other domains (eg, social, economic) and this relationship is not being detected or reported by current research practices, barriers for successful and sustainable dietary changes may not be fully understood.