title: Disproportionately increased 24-h energy expenditure and fat oxidation in young men with low birth weight during a high-fat overfeeding challenge.
abstract: BACKGROUND
  Low birth weight (LBW) associates with increased risk of developing type 2 diabetes. LBW individuals exhibit disproportionately reduced peripheral insulin action and increased fat oxidation after a 5-day high-fat overfeeding (HFO) challenge. Furthermore, LBW men exhibit increased nocturnal fat oxidation during energy balance and low energy expenditure (EE) during fasting. We hypothesized that short-term HFO could further unmask key defects of whole-body energy metabolism in LBW men.
  
  
  METHODS
  Eighteen LBW (2717 ± 268 g) and 26 normal birth weight (NBW) (3893 ± 207 g) healthy young men were included in a 5-day HFO (60 E % fat, +50 % calories) study. The 24-h EE, respiratory quotient and substrate oxidation rates were assessed by indirect calorimetry using respiratory chambers.
  
  
  RESULTS
  After adjusting for body composition, the LBW subjects displayed increased nighttime EE (P = 0.02) compared with NBW controls during HFO. Nighttime glucose oxidation rate was decreased (P = 0.06, adjusted P = 0.05), while both adjusted 24-h (P = 0.07) and nighttime (P = 0.02) fat oxidation rate was elevated in LBW subjects. The relative contribution of fat oxidation to EE was increased in LBW compared with NBW men during the entire 24-h period (P = 0.06) and during nighttime (P = 0.03).
  
  
  CONCLUSIONS
  We suggest that disproportionally enhanced fat oxidation in LBW individuals during short-term HFO represents a compensatory response to reduced subcutaneous adipose tissue expandability and storage capacity. The extent to which this mechanism may lead to, or be replaced by insulin resistance, ectopic fat accumulation and/or glucose intolerance during long-term HFO in LBW needs further studies.
authors: Steno Diabetes Center, Niels Steensens Vej 2, 2820, Gentofte, Denmark. charlotte.broens@regionh.dk.|Department of Endocrinology (Diabetes and Metabolism), Rigshospitalet, Tagensvej 20, 2200, Copenhagen, Denmark. charlotte.broens@regionh.dk.
authors: Charlotte
authors: C
authors: Brøns
authors: Novo Nordisk A/S, Novo Allé, 2880 Bagsværd, Denmark.
authors: Søren K
authors: SK
authors: Lilleøre
authors: Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958, Frederiksberg C, Denmark.
authors: Arne
authors: A
authors: Astrup
authors: Steno Diabetes Center, Niels Steensens Vej 2, 2820, Gentofte, Denmark.|Department of Endocrinology (Diabetes and Metabolism), Rigshospitalet, Tagensvej 20, 2200, Copenhagen, Denmark.
authors: Allan
authors: A
authors: Vaag
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition; D002153:Calorimetry, Indirect; D059305:Diet, High-Fat / Q000009:adverse effects*; D004041:Dietary Fats / Q000008:administration & dosage* / Q000009:adverse effects; D002149:Energy Intake; D004734:Energy Metabolism; D018149:Glucose Intolerance; D006801:Humans; D007230:Infant, Low Birth Weight / Q000254:growth & development*; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D050356:Lipid Metabolism; D008297:Male; D010084:Oxidation-Reduction; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin
keywords: Fat overfeeding; Low birth weight; Whole-body energy metabolism