Oral Presentation Australian & New Zealand Obesity Society 2015 Annual Scientific Meeting

Meal induced thermogenesis is not impaired in obese compared to healthy weight children (#28)

Kay Nguo 1 , Catherine E Huggins 1 , Elizabeth Barber 1 , Justin Brown 2 , Helen Truby 1 , Maxine P Bonham 1
  1. Department of Nutrition and Dietetics, Monash University, Melbourne, VIC, Australia
  2. Department of Paediatric Endocrinology and Diabetes, Monash Children's Hospital, Melbourne, VIC, Australia

Background/Aims: Meal induced thermogenesis (MIT) is the increase in energy expenditure after meal intake. In adults, it has been postulated that impairment in MIT may affect energy balance thus contributing to the development or maintenance of obesity. Little is known about MIT in obese children. This study aimed to determine if there is evidence of impairment of MIT between healthy weight and obese children.

Methods: An acute cross-over study with children 11-19 years old was undertaken. Participants consumed in random order, a high 79% carbohydrate (HCHO) and a high 55% (whey) protein (HP) breakfast. MIT and macronutrient oxidation rates were measured using indirect calorimetry, and self-reported hunger and fullness were assessed using visual analogue scales for four hours postprandially. Data were calculated as incremental AUC and expressed as mean ± SEM. Data were analysed using a mixed between within subjects ANOVA.

Results: Thirteen obese (35.3 ± 1.7 kg/m2) and 13 healthy weight (19.7 ± 0.7 kg/m2) children participated. Overall, compared to the HCHO meal, the HP meal induced greater MIT (258.4 ± 18.4 kJ/4hr vs 136.3 ± 11.3 kJ/4hr, p<0.001), fat oxidation (2.2 ± 0.5 g/4hr vs -4.7 ± 0.6 g/4hr, p<0.001) and fullness (12995 ± 844 mm/4hr vs 11187 ± 848 mm/4hr, p=0.016). There were no significant differences between healthy weight and obese children.

Conclusions: Obese and healthy weight children displayed comparable MIT. The greater MIT, fat oxidation and perceived feelings of fullness after the HP compared to the HCHO meal supports the role of dietary protein as an important macronutrient for energy balance and body weight management.

Funding sources: Monash University Strategic Grant and L.E.W Carty Charitable Fund.