title: Rational and design of an overfeeding protocol in constitutional thinness: Understanding the physiology, metabolism and genetic background of resistance to weight gain.
abstract: BACKGROUND
  Constitutional thinness (CT) is a natural state of underweight (13-17.5kg/m2) without the presence of any eating disorders and abnormal hormonal profile, and with preserved menses in women. We previously conducted a four-week fat overfeeding study showing weight gain resistance in CT women and one of our main results was the identification of an energy gap: a positive energy balance (higher energy intake than energy expenditure).
  
  
  OBJECTIVE
  This new overfeeding study is designed to confirm the energy gap and propose mechanistic hypothesis.
  
  
  METHODS
  A 2-week overfeeding (daily consumption of one bottle of Renutryl®Booster (600kcal, 30g protein, 72g carbohydrate, 21g fat) on top of the dietary intake) is performed to compare 15 women and men in each CT group (Body Mass Index [BMI]<18.5kg/m2) to their controls (BMI 20-25kg/m2). Bodyweight, food intake, energy expenditure (canopy, calorimetric chamber and Actiheart), body composition (DXA), appetite regulatory hormone profiles after a test meal, proteomics, metabolomics, urinary metabolic profiles, stool microbiome and lipids, fat and muscle transcriptomics are monitored before and after overfeeding.
  
  
  CONCLUSIONS
  Data inter-linking will be able to be established with results of this study. The findings could possibly open to therapeutic approaches to help CT patients to gain weight as well as provide a better understanding of energy regulation with regard to treat obesity (resistance to weight loss), a mirror image of CT (resistance to weight gain).
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism and Eating disorders, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: yiin.ling@chu-st-etienne.fr.
authors.forename: Yiin
authors.initials: Y
authors.lastname: Ling
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: bogdan.galusca@chu-st-etienne.fr.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Galusca
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: Jorg.Hager@rd.nestle.com.
authors.forename: Jorg
authors.initials: J
authors.lastname: Hager
authors.affiliation: Division of Physiology and Exercise, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: leonard.feasson@chu-st-etienne.fr.
authors.forename: Leonard
authors.initials: L
authors.lastname: Feasson
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: Armand.Valsesia@rd.nestle.com.
authors.forename: Armand
authors.initials: A
authors.lastname: Valsesia
authors.affiliation: UMR 894 INSERM Psychiatry and neurosciences center, Paris Descartes University, 2 ter rue d'Alesia, 75014 Paris, France. Electronic address: jacques.epelbaum@inserm.fr.
authors.forename: Jacques
authors.initials: J
authors.lastname: Epelbaum
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: Virginie.Alexandre@rd.nestle.com.
authors.forename: Virginie
authors.initials: V
authors.lastname: Alexandre
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: Wynn@rdls.nestle.com.
authors.forename: Emma
authors.initials: E
authors.lastname: Wynn
authors.affiliation: Nutrition and Metabolic Health Unit, Nestlé Institute of Health Sciences, EPFL Innovation Park, 1015 Lausanne, Switzerland. Electronic address: Cecile.Dinet@rdls.nestle.com.
authors.forename: Cécile
authors.initials: C
authors.lastname: Dinet
authors.affiliation: Division of Digestive Surgery, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: radu.palaghiu@chu-st-etienne.fr.
authors.forename: Radu
authors.initials: R
authors.lastname: Palaghiu
authors.affiliation: Division of Pathology, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: michel.peoch@chu-st-etienne.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Peoc'h
authors.affiliation: UMR 1019, Human Nutrition Unit, INRA, Research center Clermont-Ferrand, 63000 Clermont-Ferrand, France. Electronic address: yves.boirie@clermont.inra.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Boirie
authors.affiliation: UMR 1019, Human Nutrition Unit, INRA, Research center Clermont-Ferrand, 63000 Clermont-Ferrand, France. Electronic address: Christophe.Montaurier@clermont.inra.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Montaurier
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism and Eating disorders, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: bruno.estour@chu-st-etienne.fr.
authors.forename: Bruno
authors.initials: B
authors.lastname: Estour
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism and Eating disorders, CHU Saint-Etienne, 42055 Saint-Etienne Cedex 2, France. Electronic address: natacha.germain@chu-st-etienne.fr.
authors.forename: Natacha
authors.initials: N
authors.lastname: Germain
mesh_terms: D000293:Adolescent; D000328:Adult; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D023281:Genomics; D006801:Humans; D008297:Male; D055432:Metabolomics; D044623:Nutrition Therapy / Q000379:methods*; D044343:Overnutrition; D012107:Research Design; D013851:Thinness / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D015430:Weight Gain / Q000235:genetics*; D055815:Young Adult
keywords: Appetite regulatory hormone; Constitutional thinness; Dépense énergétique; Energy expenditure; Hormone régulatrice de l’appétit; Maigreur constitutionnelle; Metabolomics; Métabolomiques; Overfeeding; Proteomics; Protéomiques; Surnutrition