Singing as a handicap : the effects of food availability and weather on song output in the Australian reed warbler Acrocephalus australis

Bird song is generally regarded as a sexually selected trait, and may represent a reliable handicap signal under at least certain conditions. Females may use the degree of male song production as a reliable cue to male condition or territory quality. We investigated the effect of supplementary feeding on song output in the migratory Australian reed warbler Acrocephalus australis. We experimentally increased the food availability on alternate days, and recorded several weather variables. We measured song rate and song length independently. Supplementary fed birds sang more on feeding days than on non-feeding days, while control birds did not show this effect. Song output was not significantly associated with any of the weather variables examined. Our results indicate that singing has the potential to serve as a reliable handicap signal to territorial food availability irrespective of the prevailing weather conditions. We discuss the role of energetic constraints and behavioural flexibility on the signaling function of song.

Social ideological influences on food consumption and BMI

Social ideologies appeared to influence dietary behaviour, physical activity and BMI. These influences varied through different pathways in younger and older baby boomers. Studies provide insight into the segmentation of baby boomer population in relation to concrete social ideologies that could be used for policy development and effective health promotion.

Dietary patterns, assessed from a weighed food record, and survival among elderly participants from the United Kingdom

Background/Objectives: There is variability in the association between dietary intake and health outcomes across different countries, especially among the elderly. We used the gold standard dietary assessment method, a weighed food record, to examine the association between dietary pattern and mortality in a representative sample of community dwelling participants from Great Britain aged 65 years and older.

Subjects/Methods: Dietary intake was recorded at baseline in 1017 elderly participants (520 men, 497 women, mean age 76.3±7.4 years). Exploratory factor analysis was performed to examine dietary patterns and participants were followed up over an average of 9.2 years for mortality.

Results: The factor analysis revealed four interpretable principal components accounting for approximately 9.8% of the total variance, with similar patterns across sex. A ‘Mediterranean-style’ dietary pattern explained the greatest proportion of the variance (3.7%), followed by ‘health-aware’ (2.2%), ‘traditional’ (2.0%) and ‘sweet and fat’ (1.9%) factors. There were a total of 683 deaths through follow-up. After adjustment for potential confounders, only the Mediterranean-style dietary pattern remained associated with mortality (highest vs lowest tertile; hazard ratio¼0.82, 95% CI, 0.68–1.00). The benefits of the Mediterranean-style diet were only observed among women (hazard ratio¼0.71, 95% CI 0.52–0.96) although in men the traditional diet was a risk factor for mortality (hazard ratio¼1.30, 95% CI 1.00–1.71).

Conclusions: Using a gold standard approach, our results confirm previous evidence that dietary patterns are important in longevity among the elderly.

Oral sensitivity to fatty acids, food consumption and BMI in human subjects

Fatty acids are the chemical moieties that are thought to stimulate oral nutrient sensors, which detect the fat content of foods. In animals, oral hypersensitivity to fatty acids is associated with decreased fat intake and body weight. The aims of the present study were to investigate oral fatty acid sensitivity, food selection and BMI in human subjects. The study included two parts; study 1 established in thirty-one subjects (29 (sem 1·4) years, 22·8 (sem 0·5) kg/m²) taste thresholds using 3-AFC (3-Alternate Forced Choice Methodology) for oleic, linoleic and lauric acids, and quantified oral lipase activity. During study 2, fifty-four subjects (20 (sem 0·3) years, 21·5 (sem 0·4) kg/m2) were screened for oral fatty acid sensitivity using oleic acid (1·4 mm), and they were defined as hypo- or hypersensitive via triplicate triangle tests. Habitual energy and macronutrient intakes were quantified from 2 d diet records, and BMI was calculated from height and weight. Subjects also completed a fat ranking task using custard containing varying amounts (0, 2, 6 and 10 %) of fat. Study 1 reported median lipase activity as 2 μmol fatty acids/min per l, and detection thresholds for oleic, linoleic and lauric acids were 2·2 (sem 0·1), 1·5 (sem 0·1) and 2·6 (sem 0·3) mm. Study 2 identified twelve hypersensitive subjects, and hypersensitivity was associated with lower energy and fat intakes, lower BMI (P < 0·05) and an increased ability to rank custards based on fat content (P < 0·05). Sensitivity to oleic acid was correlated to performance in the fat ranking task (r 0·4, P < 0·05). These data suggest that oral fatty acid hypersensitivity is associated with lower energy and fat intakes and BMI, and it may serve as a factor that influences fat consumption in human subjects.

Maternal self-efficacy regarding children's eating and sedentary behaviours in the early years : Associations with children's food intake and sedentary behaviours

Introduction. This cross-sectional study aimed to describe parents' views regarding self-efficacy to influence children's eating and sedentary behaviours at two time points in early childhood, and to examine associations between these views and children's eating and sedentary behaviours.

Methods. Mothers of 1-year (n=60) and 5-year-old children (n=80) were recruited through Maternal and Child Health Centres and kindergartens in Victoria, Australia. Mothers reported children's dietary intake, television viewing and perceptions of their self-efficacy regarding children's eating and sedentary behaviours.

Results. Overall, 5-year-old children consumed significantly more energy-dense food and drink and spent significantly more time viewing TV/DVD and video. Mothers of 1-year-olds were significantly more likely to report they felt confident to limit child's consumption of non-core foods/drinks, and to limit screen access (p<0.001). Measures of maternal self-efficacy were directly associated with 5-year-old children's water (p<0.05), and fruit and vegetable consumption (p<0.005), and with 1-year-old children's vegetable consumption (p<0.05), and were inversely associated with cordial and cake consumption (p<0.05). Maternal self-efficacy to limit viewing time was inversely associated with screen-time exposure in both age groups (p<0.01).

Conclusion. This study suggests that mother's self-efficacy regarding limiting non-core foods/drinks and limiting screen-time exposures may decline during the first few years of a child's life. Higher maternal self-efficacy was associated with children having more obesity protective eating and sedentary behaviours at both ages. Interventions to support the development of healthy lifestyle behaviours may be most effective if they target mothers' self-efficacy in these domains early in their child's life.

Gatekeeper influence on food acquisition, food preparation and family diet

The problems associated with overweight and obesity has focused attention on obesogenic, or obesity promoting environments. The home environment, in particular the role of the main food gatekeeper, has come under particular scrutiny for its impact on the family diet (Campbell et al, 2007; Coveney, 2004; Crawford et al, 2007). 326 US and 323 Australian gatekeepers are studied to understand relationships between healthy eating capability, food acquisition and food preparation behaviours, and satisfaction with the household diet. The results suggest that gatekeeper attitudes and perceived control over family diet play a significant role in shaping food-related behaviours and diet satisfaction. Impulsiveness, focusing on freshness, meal planning, and vegetable prominence in meals are also important behavioural factors for satisfaction with diet.

Social ideological influences on reported food consumption and BMI

Background : The purpose of this study was to investigate relationships between ideological beliefs, perceptions of the importance of health behaviours, health attitudes, food consumption, and Body Mass Index (BMI). A behavioural model was hypothesized based on the Theory of Reasoned Action (Fishbein & Ajzen, 1975).

Methods : A survey was conducted among shoppers aged between 40 and 70 years at Eastland Shopping Centre, Melbourne, Australia. The hypothesized model was tested with this empirical data (n = 410) for younger (n = 151) and older (n = 259) age groups using structural equation modelling.

Results : The findings generally support the study hypotheses. For both groups, egalitarianism had a direct and positive influence on perceptions of the importance of health behaviours. Materialism and masculinity impacted negatively on health attitudes, which positively influenced importance of health behaviours. Perceptions of importance of health behaviours impacted positively on the consumption of healthy foods such as vegetables and fruits, but negatively on consumption of unhealthy foods including sweets and fats. However, BMI was significantly influenced by the consumption of unhealthy foods (e.g., sugar and fats) only for the younger age group. Hence, the associations between beliefs, attitudes, consumption behaviours, and BMI outcomes differed between younger and older age populations.

Conclusion : Social ideological beliefs appear to influence health attitudes and thereafter, the consumption of healthy and unhealthy foods and BMI via different pathways.

A population-based study of preschoolers' food neophobia and its associations with food preferences

Objective: This cross-sectional study was designed to investigate the relationships between food preferences, food neophobia, and children’s characteristics among a population-based sample of preschoolers.

Design: A parent-report questionnaire.

Setting: Child-care centers, kindergartens, playgroups, day nurseries, and swimming centers.

Subjects: 371 two- to five-year-old Australian children.

Outcome Measures: Associations between food neophobia and the food preferences and characteristics.

Analysis: Analysis of variance, analysis of covariance, Pearson product-moment correlations, and Fisher z test were used to estimate and compare the associations between these variables.

Results: Food neophobia was associated with reduced preferences for all food groups, but especially for vegetables (r = −0.60; P < .001). It was also associated with liking fewer food types (r = −0.55; P < .001), disliking more food types (r = 0.42; P < .001), the number of untried food types (r = 0.25; P < .001), a less varied range of food preferences (r = −0.59; P < .001), and less healthful food preferences overall (r = −0.55; P < .001). No significant relationships (P < .01) were observed between food neophobia and a child’s age, sex, or history of breast-feeding.

Conclusions: The study confirms and extends results obtained in experimental research and population-based intake studies of food neophobia to children’s everyday food preferences. The findings suggest that preschool children’s everyday food preferences are strongly associated with food neophobia but not with children’s age, sex, or history of breast-feeding. When aiming to influence children’s food preferences, the effects of food neophobia and strategies to reduce it should be considered.

Associations between parental concern for adolescent weight and the home food environment and dietary intake

Objective: Examine associations between parental concern about adolescent weight and adolescent perceptions of their dietary intake, home food availability, family mealtime environment, and parents' feeding practices.

Design: Cross-sectional study.

Setting: Adolescents, aged 12-15 years from 37 secondary schools in Victoria, Australia, and their parents completed surveys in 2004-2005.

Participants: 1,448 adolescent–parent pairs.

Main Outcome Measures: Parental concern about adolescent weight; adolescent perceptions of their food intake and home food environment.

Analysis: Chi-square tests, exploratory factor analysis, independent t tests (P < .01).

Results: Although 12% of parents perceived their adolescent as overweight, 27% were concerned about their adolescent's weight (under- or overweight). Adolescents of concerned parents reported lower intakes of energy-dense snacks and less home availability of these food items, and they perceived that their parents less often listened to and considered their food preferences when shopping and cooking, than did adolescents of unconcerned parents. Concerned parents were no more likely to provide fruits and vegetables in the home or a positive family mealtime environment than unconcerned parents, at least as reported by their adolescents.

Conclusions and Implications: Parental concern about adolescent weight was associated with lower intakes of energy-dense snacks among adolescents, less home availability of these food items, and less supportive parental feeding practices. Parents should be encouraged to listen to and consider their adolescents' food preferences, and provide supportive family mealtime environments and healthful food in the home.