Long Oral Presentation Nutrition Society of Australia 50th Annual Scientific Meeting 2026

Feasibility and acceptability of a food-based dietary intervention targeting approximately 800 kcal/day in adults with obesity: a pilot single-arm intervention study (144696)

Shirley WY Poon 1 2 , Jessica R Biesiekierski 1 , David JW Wang 1 , Robyn M Brown 3 , Priya Sumithran 2 4
  1. School of Agriculture, Food and Ecosystem Sciences (SAFES), Faculty of Science, University of Melbourne, Parkville, VIC, Australia
  2. Department of Medicine, St Vincent’s Hospital Melbourne, University of Melbourne, Fitzroy, VIC, Australia
  3. Department of Pharmacology and Biochemistry, University of Melbourne, Melbourne, VIC, Australia
  4. Department of Endocrinology and Diabetes, Alfred Health, Melbourne, VIC, Australia

Very-low-energy diets (VLEDs) can produce substantial short-term weight loss and improve obesity-related health outcomes, but traditional meal replacement approaches may limit opportunities for participants to develop food-related self-management skills during active weight loss. This study evaluated the feasibility, acceptability, weight loss response, safety and preliminary clinical outcomes of a pragmatic 8-week food-based dietary intervention targeting approximately 800 kcal/day in adults with obesity. In this prospective, single-arm pilot study, 10 adults eligible for VLED therapy completed an 8-week intervention targeting approximately 800 kcal/day. Participants planned, purchased and prepared all foods, supported by dietary self-monitoring and fortnightly dietitian consultations. Primary feasibility outcomes were acceptability, defined as Food Acceptability Questionnaire (1) scores ≥ 4, and weight loss response, defined as ≥5% weight loss. Secondary outcomes included recruitment, retention and engagement. Exploratory outcomes included anthropometric measures, blood pressure, nutritional and biochemical markers, dietary quality assessed using the HEIFA-2013 (2), nutritional adequacy and adverse events. Within-participant changes were assessed using paired sample t-tests for normally distributed variables and Wilcoxon signed-rank tests for non-normally distributed variables. All participants completed the intervention with 100% attendance at all study visits. Acceptability criteria were met for 9 of 10 Food Acceptability Questionnaire domains and 90% of participants achieved ≥5% weight loss. Mean weight loss was 10.8 % (95%CI -13.6, -7.9). Participants completed 93 ± 13% of expected food diary days with mean reported energy intakes of 842 ± 70 kcal/day. Although 46 ± 20% of recorded days met the ≤ 800 kcal/day target, 89 ± 7% were within the pragmatic implementation range of ≤1000 kcal/day. Significant improvements were observed in weight, BMI, waist circumference and hip circumference (all p < 0.001), systolic and diastolic blood pressure (both p < 0.002), and total and LDL cholesterol (both p < 0.002). Dietary quality improved by 10.8 points (95% CI 1.2, 20.4; p = 0.03), driven by reductions in discretionary food intake, sodium intake and percentage energy from saturated fat (all p<0.02). No clinically concerning changes were observed in other micronutrients or safety parameters, however calcium intake was below the Estimated Average Requirement for most participants throughout the intervention. Adverse events were predominantly mild to moderate. An 8-week food-based dietary intervention targeting 800 kcal/day was feasible and acceptable, with high retention, engagement and substantial short-term weight loss. These preliminary findings support evaluation in a larger controlled trial to determine efficacy, sustainability and longer-term clinical implications of a pragmatic food-based dietary intervention targeting approximately 800 kcal/day.

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  2. Roy R, Hebden L, Rangan A et al. (2016) Nutrition. 32, 432-440.