title: An adaptive response to uncertainty can lead to weight gain during dieting attempts.
abstract: OBJECTIVE
  Peoples' attempts to lose weight by low calorie diets often result in weight gain because of over-compensatory overeating during lapses. Animals usually respond to a change in food availability by adjusting their foraging effort and altering how much energy reserves they store. But in many situations the long-term availability of food is uncertain, so animals may attempt to estimate it to decide the appropriate level of fat storage.
  
  
  METHODS
  We report the results of a conceptual model of feeding in which the animal knows whether food is currently abundant or limited, but does not know the proportion of time, there will be an abundance in the long-term and has to learn it.
  
  
  RESULTS
  If the food supply is limited much of the time, such as during cycles of dieting attempts, the optimal response is to gain a lot of weight when food is abundant.
  
  
  CONCLUSIONS
  This implies that recurring attempts to diet, by signalling to the body that the food supply is often insufficient, will lead to a greater fat storage than if food was always abundant. Our results shed light on the widespread phenomenon of weight gain during weight cycling and indicate possible interventions that may reduce the incidence of obesity.
authors.affiliation: Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QG, UK a.higginson@exeter.ac.uk.|Previous address: School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
authors.forename: A D
authors.initials: AD
authors.lastname: Higginson
authors.affiliation: School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: McNamara
keywords: contrast effect; low calorie diets; obesity; optimal foraging; weight cycling; yo-yo dieting