title: Energy homeostasis and appetite regulating hormones as predictors of weight loss in men and women.
abstract: Sex differences in weight loss are often seen despite using the same weight loss program. There has been relatively little investigation of physiological influences on weight loss success in males and females, such as energy homeostasis and appetite regulating hormones. The aims were to 1) characterise baseline plasma leptin, ghrelin and adiponectin concentrations in overweight and obese males and females, and 2) determine whether baseline concentrations of these hormones predict weight loss in males and females. Subjects were overweight or obese (BMI 25-40 kg/m(2)) adults aged 18-60 years. Weight was measured at baseline, and after three and six months participation in a weight loss program. Baseline concentrations of leptin, adiponectin and ghrelin were determined by enzyme-linked immunosorbent assay (ELISA). An independent t-test or non-parametric equivalent was used to determine any differences between sex. Linear regression determined whether baseline hormone concentrations were predictors of six-month weight change. Females had significantly higher baseline concentrations of leptin, adiponectin and unacylated ghrelin as well as ratios of leptin:adiponectin and leptin:ghrelin. The ratio of acylated:unacylated ghrelin was significantly higher in males. In males and females, a higher baseline concentration of unacylated ghrelin predicted greater weight loss at six months. Additionally in females, higher baseline total ghrelin predicted greater weight loss and a higher ratio of leptin:ghrelin predicted weight gain at six months. A higher pre-weight-loss plasma concentration of unacylated ghrelin is a modest predictor of weight loss success in males and females, while a higher leptin:ghrelin ratio is a predictor of weight loss failure in females. Further investigation is required into what combinations and concentrations of these hormones are optimal for weight loss success.
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Williams
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Wood
authors.affiliation: School of Health Sciences, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Collins
authors.affiliation: School of Education, Faculty of Education and Arts, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Morgan
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia; Priority Research Centre in Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia; Hunter Medical Research Institute, New Lambton Heights, NSW, Australia. Electronic address: robin.callister@newcastle.edu.au.
authors.forename: Robin
authors.initials: R
authors.lastname: Callister
mesh_terms: D000215:Acylation; D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001066:Appetite; D015992:Body Mass Index; D004734:Energy Metabolism; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006706:Homeostasis; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000628:therapy; D050177:Overweight / Q000097:blood / Q000628:therapy; D012737:Sex Factors; D016896:Treatment Outcome; D015431:Weight Loss
chemical_list: D052242:Adiponectin; D054439:Ghrelin; D020738:Leptin
keywords: Appetite hormones; Sex differences; Weight loss