Sue Reeves

Effects of peer influence on dietary intake and physical activity in schoolchildren

OBJECTIVE To investigate the dietary intake and physical activity of boys and girls aged 9-13 years, and the influence of peers on these behaviours. DESIGN Cross-sectional study. SETTING Nine primary and secondary schools in south-west London. SUBJECTS A total of 315 children wore sealed pedometers, provided self-report measures of dietary intake and answered a questionnaire relating to peer influence. Anthropometric measures of height and weight were also obtained. RESULTS Obese children had the lowest reported energy intakes and the lowest step counts per day. Boys took significantly more steps per day than girls, however girls were closer to achieving their recommended cut-offs for physical activity. Girls had lower energy intakes per day and lower BMI Z-scores than boys, however both genders, across all age groups, had higher than recommended intakes of saturated fat. There were significant associations between peer influence and physical activity levels but not between peer influence and dietary intake. CONCLUSIONS Low energy intake and physical activity levels but high saturated fat intakes among boys and girls across all age groups highlight the importance of promoting both physical activity and healthy food choices. The finding that peers have a significant effect on physical activity levels but not on dietary intake offers an important approach for the design of health promotion interventions and obesity prevention programmes. Such designs may be particularly beneficial for obese youth, since the low physical activity levels found could be a major contributing factor to the maintenance of the condition.

Breakfast habits, beliefs and measures of health and wellbeing in a nationally representative UK sample

The aim of this study was to report UK adult breakfasting habits, beliefs and the relationship of both with measures of personality, health and wellbeing including physical activity and body mass index (BMI). A nationally representative sample of 1068 adults completed a web-based survey, combining standardised scales and self-designed questionnaire statements. Sixty-four percent of respondents consumed breakfast daily whilst 6% never ate breakfast. Breakfasting frequency was found to correlate with conscientiousness, wellbeing and age and general health. The survey found that breakfast eaters strongly believe that breakfast helps weight control and weight loss. Breakfast eaters were more likely to partake in vigorous exercise, although there was no significant difference in BMI. Multi-variate analysis identified conscientiousness, cognitive restraint and age as making unique contributions to predicting breakfast frequency. This study provides further support for the view that breakfast eating is likely to be a proxy-variable for a healthy lifestyle. The role of breakfast and related beliefs should be taken into consideration in breakfast behaviour research, interventions and health and wellbeing campaigns.

Does consuming breakfast influence activity levels? An experiment into the effect of breakfast consumption on eating habits and energy expenditure

OBJECTIVE To experimentally compare the effects of eating or skipping breakfast on energy expenditure, activity levels and dietary habits. DESIGN A randomised cross-over trial, lasting 2 weeks. Participants were provided breakfast during one week and were required to fast until mid-day during the other week. SETTING University campus. SUBJECTS Forty-nine participants (twenty-six female and twenty-three male participants) were recruited. Food intake was monitored using food diaries, and energy expenditure was assessed using pedometers and heart rate monitors. Morningness-eveningness, physical activity and health were assessed using validated questionnaires. RESULTS Across all participants, daily energy expenditure did not differ between the two experimental conditions. Total energy intake over 24 h did not vary with condition (male participants: 8134 (sd 447) kJ/d and 7514 (sd 368) kJ/d; female participants: 7778 (sd 410) kJ/d and 7531 (sd 535) kJ/d, for the breakfast and no-breakfast conditions, respectively). However, when comparing habitual breakfast eaters with those with irregular or breakfast-skipping habits, it was found that male non-habitual breakfast eaters consumed significantly (P = 0·029) more energy during the breakfast condition. Furthermore, female participants who were habitual breakfast eaters were found to eat significantly (P = 0·005) more and later in the day under the no-breakfast condition. CONCLUSIONS Although the suggestion that breakfast is a behavioural marker for appropriate dietary and physical activity patterns is not refuted by the present findings, our data suggest that the effect of breakfast may vary as a function of gender and morning eating habits, and thus there may be other mechanisms that link BMI and breakfast consumption behaviour.

Physical activity and dietary intake of children aged 9-11 years and the influence of peers on these behaviours: a 1-year follow-up.

Background:This study investigated physical activity and dietary intake of children aged 9–11 years, and the influence of peers on these behaviours over a 2-year period.Methods:A total of 106 (64 girls; 42 boys) children were investigated annually, over 2 years. Measures included physical activity (sealed pedometer), self-report measures of dietary intake and physical activity, and a peer influence questionnaire. Anthropometric measures of height and weight were also obtained.Results:The findings reveal insufficient energy intakes, physical activity levels and fruit and vegetable consumption but high intakes of saturated fat and sodium, over time, in both boys and girls. Both male calcium and female iron intakes were also of concern. Throughout the survey, peers were found to influence physical activity behaviour but not dietary intake.Conclusions:The fact that youth consistently failed to meet established nutrition and physical activity recommendations highlights the importance of promoting physical activity and healthy eating to children younger than 9 years of age. The finding that peers significantly influence physical activity behaviour over time should be considered when designing new physical activity interventions aimed at young people.

Habitual dietary intake, eating pattern and physical activity of women with polycystic ovary syndrome

Background/Objective:Diet and lifestyle modifications may be of benefit in the management of polycystic ovary syndrome (PCOS), but there is a paucity of data on these behaviours in women with PCOS. This study aims to address this through a comprehensive investigation of the habitual diet and activity patterns of UK women with PCOS and their alignment with dietary recommendations for health.Subjects/Methods:A 7-day-estimated food and activity diary and questionnaire was completed by 210 women with PCOS for calculation of activity levels, energy and nutrient intakes and dietary glycaemic index (GI).Results:Mean (s.d.) body mass index (BMI) was 27.4 (7.3) kg/m2 (n=183), with 53% of women with PCOS having a BMI>25 kg/m2. Of the overweight women, approximately half were not achieving sufficient physical activity to promote weight loss. More frequent eating episodes and a lower BMI were weakly associated (r=−0.158, P=0.034). Mean percentage energy from fat was 38 (7)% (12% energy from saturated fat), with 68% of women with PCOS consuming > 35% energy from fat. Mean dietary GI was higher in obese women with PCOS, compared with healthy weight women with PCOS (55.7 (3.4) and 53.8 (4.0), respectively; P=0.043).Conclusion:Many women with PCOS are not achieving dietary intakes and levels of physical activity that optimise symptom management and disease prevention. Advice should focus on fat quality and quantity and carbohydrate modification. There is a need for further robust research into the role of dietary GI in the PCOS population.

An Isocaloric Low Glycemic Index Diet Improves Insulin Sensitivity in Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder affecting 5% to 10% of women worldwide. Approximately half of women with PCOS are lean, yet may still present with central obesity and metabolic disturbances. Low-glycemic index (GI) dietary intervention studies have demonstrated improvements in insulin sensitivity in insulin-resistant populations; however, there is little evidence of this effect in women with PCOS. This research aimed to determine the efficacy of an isocaloric low-GI dietary intervention on insulin sensitivity, independent of weight change, in women with PCOS. A nonrandomized 12-week low-GI dietary intervention, preceded by a 12-week habitual diet control phase and proceeded by a 12-week follow-up phase was conducted. Dietary intake, body composition, and metabolic risk markers were determined at baseline, after completion of the habitual diet control phase, and after the low-GI dietary intervention. Twenty-six participants were recruited at baseline, 22 commenced and 21 participants completed the low-GI dietary intervention phase. The primary outcome was change in insulin sensitivity. Secondary outcomes included assessment of changes to lipids, body composition, and estimated macronutrient intake. Repeated measures analysis of variance with Bonferroni correction were used to detect changes to outcomes across study timepoints. Twenty-one women with PCOS with mean (± standard deviation) age of 32.1±6.7 years completed the 12-week low-GI dietary intervention. As expected, no significant changes occurred during the 12-week habitual diet control phase. However, during the dietary intervention phase, dietary GI decreased from 54.5±3.5 to 48.6±5.1 (P<0.001) with a concurrent small reduction in saturated fat intake (12.4%±3% to 11.7%±3% contribution from energy, P=0.03), despite no specific recommendations to modify fat intake. Measures of insulin sensitivity and nonesterified fatty acid improved after intervention (P=0.03 and P=0.01, respectively). This is the first study to implement an isocaloric low-GI diet in women with PCOS and findings may contribute to the limited research in this area.

Experimental manipulation of breakfast in normal and overweight/obese participants is associated with changes to nutrient and energy intake consumption patterns

The effect of breakfast and breakfast omission on daily food intake in normal and overweight participants was investigated. 37 participants were recruited for this experimental study and assigned to one of four groups on the basis of their body mass index (BMI) (normal weight BMI <25 kg/m(2) or overweight/obese BMI >25 kg/m(2)) and breakfast habits (breakfast eater or breakfast omitter). All participants were requested to eat breakfast for an entire week, and then following a washout period, omit breakfast for an entire week, or vice versa. Seven-day food diaries reporting what was consumed and the timing of consumption were completed for each breakfast condition. Overall more energy was consumed during the breakfast than the no breakfast week. The present study revealed significant effects of timing on energy intakes; more energy was consumed during the afternoon in the no breakfast week compared to the breakfast week. Overweight participants consumed greater amounts of energy than normal weight participants in the early evening. Breakfast omitters consumed more than did breakfast eaters later in the evening. All groups consumed significantly less energy, carbohydrate and fibre in the no breakfast week; however, overweight participants increased their sugar intakes. Consumption of the micronutrients iron and folate was reduced in the no breakfast week. The findings highlight that the timing of food intake and habitual breakfast eating behaviour are important factors when investigating why breakfast consumption may be associated with BMI.

Beverage consumption and BMI of British schoolchildren aged 9–13 years

OBJECTIVE Adequate fluid intake has been well documented as important for health but whether it has adverse effects on overall energy and sugar intakes remains under debate. Many dietary studies continue to refrain from reporting on beverage consumption, which the present study aimed to address. DESIGN A cross-sectional survey investigated self-reported measures of dietary intake and anthropometric measurements. SETTING Primary and secondary schools in south-west London, UK. SUBJECTS Boys and girls (n 248) aged 9–13 years. RESULTS Boys consumed 10 % and girls consumed 9 % of their daily energy intake from beverages and most children had total sugar intakes greater than recommended. Beverages contributed between a quarter and a third of all sugars consumed, with boys aged 11–13 years consuming 32 % of their total sugar from beverages. There was a strong relationship between consumption of beverages and energy intake; however, there was no relationship between beverage type and either BMI or BMI Z-score. Fruit juices and smoothies were consumed most frequently by all girls and 9–10-year-old boys; boys aged 11–13 years preferred soft drinks and consumed more of their daily energy from soft drinks. Milk and plain water as beverages were less popular. CONCLUSIONS Although current health promotion campaigns in schools merit the attention being given to improving hydration and reducing soft drinks consumption, it may be also important to educate children on the energy and sugar contents of all beverages. These include soft drinks, as well as fruit juices and smoothies, which are both popular and consumed regularly.

Body mass, frequency of eating and breakfast consumption in 9–13-year-olds

BACKGROUND Unhealthy eating patterns in childhood can lead to adverse health conditions, particularly obesity. However, debate remains around the precise eating behaviours that lead to these conditions. The present study aimed to address this lack of evidence by reporting on the eating frequency, breakfast consumption and body mass index (BMI, kg m(-2) ) of youth in the UK. METHODS A total of 264 (133 boys and 131 girls) participants, aged 10-13years, completed self-report measures of dietary intake via 3-day food/drink diaries (Friday to Sunday). Trained researchers recorded height and weight to calculate the BMI. Diaries were analysed using dietplan 6 nutritional analysis software (Forestfield Software, Horsham, UK) and multivariate linear regression was used to examine any association between breakfast consumption, frequency of eating and BMI. RESULTS No relationship existed between BMI Z-score, eating frequency and breakfast consumption. However, frequent breakfast consumers had significantly lower mean (SD) BMI Z-scores [0.18(1.06) versus 0.57(1.23)] and higher intakes of iron, calcium and vitamin E than those who did not eat breakfast regularly. Those aged ≥11years consumed breakfast less frequently [0.92(0.20)] and were less likely to eat regularly [4.6(1.4)] than those aged ≤10years. CONCLUSIONS Older boys were the least likely to eat regularly and the least likely to consume breakfast. Promoting the importance of regular eating, particularly breakfast consumption to these boys, may be essential to ensure healthier, long-term eating patterns. Furthermore, the lower breakfast intakes in 11-13-year-olds and higher BMI Z-scores of those who did not eat breakfast regularly should be monitored.

A cross-over experiment to investigate possible mechanisms for lower BMIs in people who habitually eat breakfast

Background/Objectives:The body mass index (BMI) of breakfast eaters is frequently reported to be lower compared with that of breakfast skippers. This is not explained by differences in energy intakes, indicating there may be other mechanisms serving to drive this paradoxical association between breakfast and BMI. This study aimed to investigate the effect of eating breakfast versus morning fasting on measures predominantly of metabolism in lean and overweight participants who habitually eat or skip breakfast.Subjects/Methods:Participants (n=37) were recruited into four groups on the basis of BMI (lean and overweight) and breakfast habit (breakfast eater and breakfast skipper). Participants were randomly assigned to a breakfast experimental condition, breakfast eating or no breakfast, for 7 days and then completed the alternative condition. At the end of each breakfast experimental condition, measurements were made before and after a high carbohydrate breakfast of 2274±777 kJ or a rest period. Resting metabolic rate, thermic effect of food (TEF), blood glucose, insulin and leptin levels were recorded. Hunger and ‘morningness’ were assessed and pedometers worn.Results:Lean participants had lower fasting insulin levels (P=0.045) and higher insulin concentrations following breakfast (P=0.001). BMI and breakfast habit did not interact with the experimental breakfast condition, with the exception of hunger ratings; breakfast eaters were hungrier in the mornings compared with breakfast skippers in the no breakfast condition (P=0.001).Conclusions:There is little evidence from this study for a metabolic-based mechanism to explain lower BMIs in breakfast eaters.