ESPEN 2013 - Late breaking abstract submission

Late Breaking Abstract

ESPEN13-1795

IMPACT OF BODY COMPOSITION ON WEIGHT CHANGE-ASSOCIATED CHANGES IN RESTING ENERGY EXPENDITURE AND METABOLIC RISKS IN OVERWEIGHT ADULTS

M. Pourhassan ^1,*A. Bosy-Westphal ²B. Schautz ¹W. Braun ¹C.-C. Glüer ³M. Müller ¹

¹Institute of Human Nutrition and Food Science, Kiel, ²Institute of Nutritional Medicine, Stuttgart, ³Department of Diagnostic Radiology,Universitätsklinikum , Kiel, Germany

Rationale: To investigate changes in the components of either fat free mass (FFM) or fat mass (FM) with weight change to assess how they add to the variances in REE (resting energy expenditure) and metabolic risks, e.g. insulin resistance.

Methods: 83 healthy subjects (BMI range between 20.2 and 46.8 kg/m²) were investigated at two occasions with body weight changes between -11.2 kg to +6.5 kg within a follow-up periods between 23.5 and 43.5 months. Body composition was measured by the 4 component model together with whole body MRI (magnetic resonance imaging) to assess high and low metabolic rate organs as well as individual fat depots. REE, plasma thyroid hormone concentrations and metabolic risk factors were measured by standard methods.

Results: Weight loss was associated with decreases in FM and FFM by 79.5 and 20.5%, respectively. By contrast, 87.9% of weight gain was due to FM. With weight loss, the sizes of skeletal muscle, kidney, heart and all individual fat depots decreased. With weight gain, the volumes of skeletal muscle, liver, kidney and different adipose tissues increased except for visceral adipose tissue (VAT).  After adjustments for FM and FFM, REE decreased with weight loss (by 0.22 MJ/d), and increased with weight gain (by 0.11 MJ/d). In a multiple stepwise regression analysis, weight change-associated changes in skeletal muscle, plasma T₃ concentrations and kidney mass explained 34.9%, 5.3% and 4.5% of the variance in changes in REE. Cardio-metabolic risk factors were related to changes in FM. Reduction subcutaneous adipose tissue (SAT) rather than VAT was associated with the improvement of the HOMA Index with weight loss. By contrast, weight gain had no effect on insulin resistance.

Conclusion: Changes in individual body components add to explain weight change-associated changes in REE and metabolic risks.

Disclosure of Interest: None Declared

Keywords: resting energy expenditure weight change