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Author (up) Alcock, J.; Maley, C.C.; Aktipis, C.A. file  url
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  Title Is eating behavior manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms Type Journal Article
  Year 2014 Publication BioEssays : News and Reviews in Molecular, Cellular and Developmental Biology Abbreviated Journal Bioessays  
  Volume 36 Issue 10 Pages 940-949  
  Keywords Animals; *Biological Evolution; *Feeding Behavior; Gastrointestinal Tract/*microbiology; Humans; *Microbiota; Models, Biological; Obesity/etiology; Cravings; Evolutionary conflict; Host manipulation; Microbiome; Obesity  
  Abstract Microbes in the gastrointestinal tract are under selective pressure to manipulate host eating behavior to increase their fitness, sometimes at the expense of host fitness. Microbes may do this through two potential strategies: (i) generating cravings for foods that they specialize on or foods that suppress their competitors, or (ii) inducing dysphoria until we eat foods that enhance their fitness. We review several potential mechanisms for microbial control over eating behavior including microbial influence on reward and satiety pathways, production of toxins that alter mood, changes to receptors including taste receptors, and hijacking of the vagus nerve, the neural axis between the gut and the brain. We also review the evidence for alternative explanations for cravings and unhealthy eating behavior. Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating.  
  Call Number Serial 2002  
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Author (up) Boyd, W.A.; Cole, R.D.; Anderson, G.L.; Williams, P.L. file  url
openurl 
  Title The effects of metals and food availability on the behavior of Caenorhabditis elegans Type Journal Article
  Year 2003 Publication Environmental Toxicology and Chemistry / SETAC Abbreviated Journal Environ Toxicol Chem  
  Volume 22 Issue 12 Pages 3049-3055  
  Keywords Animals; Biological Assay; Cadmium/*toxicity; *Caenorhabditis elegans; Copper/*toxicity; *Environmental Exposure; *Feeding Behavior; Lead/*toxicity; Sensitivity and Specificity; Starvation; Water Pollutants/*toxicity  
  Abstract Caenorhabditis elegans, a nonparasitic soil nematode, was used to assess the combined effects of metal exposures and food availability on behavior. Movement was monitored using a computer tracking system after exposures to Cu, Pb, or Cd while feeding was measured as a change in optical density (deltaOD) of bacteria suspensions over the exposure period. After 24-h exposures at high and low bacteria concentrations, movement was decreased in a concentration-dependent fashion by Pb and Cd but feeding reductions were not directly proportional to exposure concentrations. Copper exposure induced concentration-dependent declines in feeding and movement regardless of bacteria concentration. The impact of 24-h metal exposures was apparently reduced by increasing food availability. Therefore, exposures were shortened to 4 h in an attempt to minimize starvation effects on movement. Although nematodes were immobilized following 24 h of food depravation, worms deprived of food during the 4-h exposure continued to feed and move after exposure. A bead-ingestion assay after 4-h exposures was also used as an additional means of assessing the effects of metals on feeding behavior. Ingestion was significantly reduced by all concentrations of metals tested, indicating its sensitivity as a sublethal assay. Feeding (deltaOD) during exposures exhibited similar trends as ingestion but was slightly less sensitive, while movement was the least sensitive assay of 4-h metal exposures to C. elegans. Assessment of multiple sublethal endpoints allowed for the determination of the separate and interactive effects of metals and food availability on C. elegans behavior.  
  Call Number Serial 1031  
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Author (up) English, L.; Lasschuijt, M.; Keller, K.L. file  url
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  Title Mechanisms of the portion size effect. What is known and where do we go from here? Type Journal Article
  Year 2015 Publication Appetite Abbreviated Journal Appetite  
  Volume 88 Issue Pages 39-49  
  Keywords Cues; *Feeding Behavior; Humans; Portion Size/*psychology; Eating behavior; Mechanisms; Portion size  
  Abstract Childhood obesity is a persistent problem worldwide, and of particular concern in the United States. Clarifying the role of the food environment in promoting overeating is an important step toward reducing the prevalence of obesity. One potential contributor to the obesity epidemic is the increased portion sizes of foods commonly served. Portion sizes of foods served both at home and away from home have dramatically increased over the past 40 years. Consistently, short-term studies have demonstrated that increasing portion size leads to increased food intake in adults and children, a phenomenon known as the portion size effect. However, the mechanisms underlying this effect are poorly understood. Understanding these mechanisms could assist in clarifying the relationship between portion size and weight status and help inform the development of effective obesity interventions. First, we review the role of visual cues, such as plate size, unit, and utensil size as a potential moderator of the portion size effect. In addition, we discuss meal microstructure components including bite size, rate, and frequency, as these may be altered in response to different portion sizes. We also review theories that implicate post-ingestive, flavor-nutrient learning as a key moderator of the portion size effect. Furthermore, we present preliminary data from an ongoing study that is applying neuroimaging to better understand these mechanisms and identify modifiable child characteristics that could be targeted in obesity interventions. Our tentative findings suggest that individual differences in cognitive (e.g. loss of control eating) and neural responses to food cues may be critical in understanding the mechanisms of the portion size effect. To advance this research area, studies that integrate measures of individual subject-level differences with assessment of food-related characteristics are needed.  
  Call Number Serial 1644  
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Author (up) Rogers, P.J.; Hill, A.J. file  url
openurl 
  Title Breakdown of dietary restraint following mere exposure to food stimuli: interrelationships between restraint, hunger, salivation, and food intake Type
  Year 1989 Publication Addictive Behaviors Abbreviated Journal Addict Behav  
  Volume 14 Issue 4 Pages 387-397  
  Keywords Adolescent; Adult; Diet, Reducing/*psychology; Energy Intake; *Feeding Behavior; Female; Humans; *Hunger; *Salivation; *Taste; Weight Loss  
  Abstract It was hypothesised that the hunger-enhancing effects of exposure to the sight and smell of palatable food would disinhibit eating in restrained eaters (self-reported dieters). In two experiments exposure to palatable food stimuli led to increases in motivational (hunger) ratings and salivation, and was followed by overeating in restrained subjects compared with the control condition (no food during exposure) and a condition in which nonpreferred food was presented during the exposure phase. The food intake of unrestrained subjects, on the other hand, was reduced following exposure to palatable food in the first experiment. This shows that breakdown of dietary restraint can be induced by food stimuli even when the food does not constitute a preload. Mere exposure to the sight and smell of palatable food is sufficient to precipitate loss of dieting motivation. The effects of exposure on hunger and salivation were, in general, unrelated to food intake or degree of dietary restraint. Therefore, changes in hunger do not appear to directly mediate increased food intake in dieters. Instead, it is tentatively suggested that anxiety resulting from exposure to liked food may play a role both in disinhibiting eating and suppressing salivation in restrained subjects.  
  Call Number Serial 1063  
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Author (up) Rollins, B.Y.; Loken, E.; Savage, J.S.; Birch, L.L. file  url
openurl 
  Title Effects of restriction on children's intake differ by child temperament, food reinforcement, and parent's chronic use of restriction Type Journal Article
  Year 2014 Publication Appetite Abbreviated Journal Appetite  
  Volume 73 Issue Pages 31-39  
  Keywords Appetite; Child, Preschool; *Diet; Eating; *Energy Intake; *Feeding Behavior; Female; Food Preferences; Humans; Inhibition (Psychology); Male; *Parent-Child Relations; Parenting; Parents; Pediatric Obesity/*etiology; *Reinforcement (Psychology); Risk Factors; Social Control, Informal; Surveys and Questionnaires; *Temperament  
  Abstract Parents' use of restrictive feeding practices is counterproductive, increasing children's intake of restricted foods and risk for excessive weight gain. The aims of this research were to replicate Fisher and Birch's (1999b) original findings that short-term restriction increases preschool children's (3-5 y) selection, intake, and behavioral response to restricted foods, and to identify characteristics of children who were more susceptible to the negative effects of restriction. The experiment used a within-subjects design; 37 children completed the food reinforcement task and heights/weights were measured. Parents reported on their use of restrictive feeding practices and their child's inhibitory control and approach. Overall, the findings replicated those of and revealed that the effects of restriction differed by children's regulatory and appetitive tendencies. Greater increases in intake in response to restriction were observed among children lower in inhibitory control, higher in approach, who found the restricted food highly reinforcing, and who had previous experience with parental use of restriction. Results confirm that the use of restriction does not reduce children's consumption of these foods, particularly among children with lower regulatory or higher appetitive tendencies.  
  Call Number Serial 1940  
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Author (up) Wilkinson, D.M.; Ruxton, G.D. file  url
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  Title Understanding selection for long necks in different taxa Type Journal Article
  Year 2012 Publication Biological Reviews of the Cambridge Philosophical Society Abbreviated Journal Biol Rev Camb Philos Soc  
  Volume 87 Issue 3 Pages 616-630  
  Keywords Animals; *Biological Evolution; Extremities/anatomy & histology; *Feeding Behavior; Neck/*anatomy & histology  
  Abstract There has been recent discussion about the evolutionary pressures underlying the long necks of extant giraffes and extinct sauropod dinosaurs. Here we summarise these debates and place them in a wider taxonomic context. We consider the evolution of long necks across a wide range of (both living and extinct) taxa and ask whether there has been a common selective factor or whether each case has a separate explanation. We conclude that in most cases long necks can be explained in terms of foraging requirements, and that alternative explanations in terms of sexual selection, thermoregulation and predation pressure are not as well supported. Specifically, in giraffe, tortoises, and perhaps sauropods there is likely to have been selection for high browsing. It the last case there may also have been selection for reaching otherwise inaccessible aquatic plants or for increasing the energetic efficiency of low browsing. For camels, wading birds and ratites, original selection was likely for increased leg length, with correlated selection for a longer neck to allow feeding and drinking at or near substrate level. For fish-eating long-necked birds and plesiosaurs a small head at the end of a long neck allows fast acceleration of the mouth to allow capture of elusive prey. A swan's long neck allows access to benthic vegetation, for vultures the long neck allows reaching deep into a carcass. Geese may be an unusual case where anti-predator vigilance is important, but so may be energetically efficient low browsing. The one group for which we feel unable to draw firm conclusions are the pterosaurs, this is in keeping with the current uncertainty about the biology of this group. Despite foraging emerging as a dominant theme in selection for long necks, for almost every taxonomic group we have identified useful empirical work that would increase understanding of the selective costs and benefits of a long neck.  
  Call Number Serial 1599  
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