Comparing the effectiveness of general dietary advice versus a very low energy diet in an obese outpatient population in Australia.

PURPOSE: Obesity is a major public health burden. Outpatient clinics are an essential resource for individuals with obesity to access advice for weight loss management. The aim of this study was to compare anthropometric and weight loss outcomes between participants receiving general dietary (GD) advice, and those on a very low energy diet (VLED) under non-trial conditions.

METHODS: Data from 276 adults with obesity attending a multidisciplinary weight management clinic were analysed. Changes in anthropometry, body composition, and blood pressure (BP) over 12 months were analysed using linear mixed-effects models.

RESULTS: Males on the GD demonstrated statistically greater reductions in body weight (BW), BMI, percent fat mass (FM), systolic BP, waist and hip circumference (p < 0.01). Changes in males on a VLED did not reach significance. Females showed statistically significant reductions in BW, BMI, waist and hip circumference regardless of dietary intervention (p < 0.01); those on the GD significantly reduced percent FM (p < 0.001). Females on a VLED had statistically greater reductions in BW, BMI and systolic BP compared to those on the GD. No effect of exercise physiologist was observed in this study. Participants prescribed a GD attended for significantly longer than those on a VLED (p < 0.05), irrespective of gender. At 12 months, 14.3 and 4.5% of males and females on a VLED were still attending, compared to 10.6 and 4.5% on the GD.

CONCLUSIONS: In this retrospective study, females in both dietary intervention groups achieved significant changes across multiple measures. Only men receiving GD advice demonstrated significant changes.

LEVEL OF EVIDENCE: Level II-2.