Sep 14, 2025
1:00 PM2:00 PM
Poster Session
P598 - DISCREPANCIES BETWEEN INDIRECT CALORIMETRY, HIGH BMI, AND LOW REPORTED ENERGY INTAKE IN OVERWEIGHT AND OBESE WOMEN SEEKING REPRODUCTIVE ASSISTANCE
P598
DISCREPANCIES BETWEEN INDIRECT CALORIMETRY, HIGH BMI, AND LOW REPORTED ENERGY INTAKE IN OVERWEIGHT AND OBESE WOMEN SEEKING REPRODUCTIVE ASSISTANCE
L. Sablon1,2, M. Vanmeerbeek1,2,*, F. Van de Velde1,2, B. Jimenez Garcia1,2, L. Leemans1,2, C. Blockeel3,4, E. De Waele1,2
1Vitality Research Group, Vrije Universiteit Brussel, 2Clinical Nutrition , Universitair Ziekenhuis Brussel, 3Genetics, Reproduction and Development Research Group, Vrije Universiteit Brussel, 4Centre for Reproductive Medicine, Brussels IVF, Universitair Ziekenhuis Brussel, Brussels, Belgium
Rationale: Overweight and obesity are linked to reduced oocyte retrieval, lower pregnancy rates, and higher miscarriage risk in IVF. Preconception personalised dietary counselling may be beneficial, but underreporting of food intake correlates positively with BMI1. This study compared reported energy intake with measured energy expenditure in overweight and obese women undergoing fertility treatment.
Methods: 946 women (BMI ≥25 kg/m²) seeking reproductive assistance were analysed. Resting energy expenditure (REE) was measured by indirect calorimetry; dietary intake using self-reported 3-day food diaries; and body composition was assessed via bioelectrical impedance analysis (BIA). Energy intake was calculated by a dietitian using the NUBEL food database. Total energy expenditure (TEE) was estimated using physical activity levels. Data are reported as mean ± standard deviation.
Results: Participants had a mean age of 33.8 ± 5.4 years, BMI of 35.8 ± 4.1 kg/m², and fat mass of 44.7 ± 4.6%. Measured REE averaged 1871.3 ± 301.5 kcal/day (19.4 kcal/kg/day), while reported intake was 1660.6 ± 480.7 kcal/day (17.3 kcal/kg/day), resulting in a 211 kcal/day (2.1 kcal/kg/day) gap. When considering TEE (2305.2 kcal/day, 23.7 kcal/kg/day), the deficit widened to 645 kcal/day (6.4 kcal/kg/day). Food diaries also showed large day-to-day fluctuations, suggesting inconsistencies in reported intake.
Conclusion: Reported energy intake was 645 kcal/day below estimated needs, indicating that metabolic adaptation, energy conservation, or underreporting may contribute to persistent obesity in this group. Further research should evaluate home-based monitoring tools for diet and activity in preconception care.
References: 1. Wehling H, Lusher J. People with a body mass index ⩾30 under-report their dietary intake: A systematic review. J Health Psychol. 2019 Dec;24(14):2042-2059.
Disclosure of Interest: None declared