Feasibility and acceptability of a brief routine weight management intervention for postnatal women embedded within the national child immunisation programme in primary care: randomised controlled cluster feasibility trial

BACKGROUND

The prevalence of obesity in women continues to rise and pregnancy is a high-risk time for excessive weight gain. The period after childbirth represents an opportunity to offer women support to manage their weight. The primary aim here was to investigate the acceptability and feasibility of delivering a self-management intervention to postnatal women to support weight loss, embedded within the national child immunisation programme.

METHODS

The research involved a randomised controlled cluster feasibility trial. Data were collected at baseline and 3 months later. Twenty-eight postnatal women living with overweight or obesity were recruited via Birmingham Women Hospital or general practices. Babies are routinely immunised at 2, 3 and 4 months of age; the intervention was embedded within these appointments. The intervention involved brief motivation/support by practice nurses to encourage participants to make healthier lifestyle choices through self-monitoring of weight and signposting to an online weight management programme, when they attended their practice to have their child immunised. The role of the nurse was to provide external accountability for weight loss. Participants were asked to weigh themselves weekly and record this on a record card or using the online programme. The weight goal was for participants to lose 0.5 to 1 kg per week. Usual care received a healthy lifestyle leaflet. The primary outcome was the feasibility of a phase III trial to test the subsequent effectiveness of the intervention, as assessed against three stop-go traffic light criteria (recruitment, adherence to regular self-weighing and registration with an online weight management programme).

RESULTS

The traffic light stop-go criteria results were red for recruitment (28/80, 35% of target), amber for registration with the online weight loss programme (9/16, 56%) and green for adherence to weekly self-weighing (10/16, 63%). Nurses delivered the intervention with high fidelity.

DISCUSSION

Whilst participants and nurses followed the trial protocol well and adherence to self-weighing was acceptable, recruitment was challenging and there is scope to improve engagement with the online weight management programme component of the intervention.

TRIAL REGISTRATION

ISRCTN 12209332 . Registration date is 04/12/18.

Reductions in sugar sales from soft drinks in the UK from 2015 to 2018

BACKGROUND

The consumption of free sugars in the UK is more than double the guideline intake for adults and close to triple for children, with soft drinks representing a significant proportion. The aim of this study was to assess how individual soft drink companies and consumers have responded to calls to reduce sugar consumption, including the soft drink industry levy (SDIL), between 2015 and 2018.

METHODS

This was an annual cross-sectional study using nutrient composition data of 7377 products collected online, paired with volume sales data for 195 brands offered by 57 companies. The main outcome measures were sales volume, sugar content and volume of sugars sold by company and category, expressed in total and per capita per day terms.

RESULTS

Between 2015 and 2018, the volume of sugars sold per capita per day from soft drinks declined by 30%, equivalent to a reduction of 4.6 g per capita per day. The sales-weighted mean sugar content of soft drinks fell from 4.4 g/100 ml in 2015 to 2.9 g/100 ml in 2018. The total volume sales of soft drinks that are subject to the SDIL (i.e. contain more than 5 g/100 ml of sugar) fell by 50%, while volume sales of low- and zero-sugar (< 5 g/100 ml) drinks rose by 40%.

CONCLUSION

Action by the soft drinks industry to reduce sugar in products and change their product portfolios, coupled with changes in consumer purchasing, has led to a significant reduction in the total volume and per capita sales of sugars sold in soft drinks in the UK. The rate of change accelerated between 2017 and 2018, which also implies that the implementation of the SDIL acted as an extra incentive for companies to reformulate above and beyond what was already being done as part of voluntary commitments to reformulation, or changes in sales driven by consumer preferences.

The equity impact of brief opportunistic interventions to promote weight loss in primary care: secondary analysis of the BWeL randomised trial

BACKGROUND

Guidelines recommend that clinicians should make brief opportunistic behavioural interventions to patients who are obese to increase the uptake of effective weight loss programmes. The objective was to assess the effect of this policy on socioeconomic equity.

METHODS

One thousand eight hundred eighty-two consecutively attending patients with obesity and who were not seeking support for weight loss from their GP were enrolled in a trial. Towards the end of each consultation, GPs randomly assigned participants to one of two 30-s interventions. In the active intervention (support arm), the GP offered referral to a weight management group. In the control intervention (advice arm), the GP advised the patient that their health would benefit from weight loss. Agreement to attend a behavioural weight loss programme, attendance at the programme and weight loss at 12 months were analysed by socioeconomic status, measured by postcode using the Index of Multiple Deprivation (IMD).

RESULTS

Mean weight loss was 2.43 kg (sd 6.49) in the support group and 1.04 kg (sd 5.50) for the advice only group, but these effects were moderated by IMD (p = 0.039 for the interaction). In the support arm, weight loss was greater in higher socioeconomic groups. Participants from lower socioeconomic backgrounds were more likely to accept the offer and equally likely to attend a weight loss referral but attended fewer sessions. Adjusting for these sequentially reduced the gradient for the association of socioeconomic status with weight loss from + 0.035 to - 0.001 kg/IMD point. In the advice only arm, 10% took effective action to promote weight loss. The decision to seek support for weight loss outside of the trial did not differ by socioeconomic status, but weight loss among deprived participants who used external support was greater than among more affluent participants (p = 0.025).

CONCLUSION

Participants' responses to GPs' brief opportunistic interventions to promote weight loss differed by socioeconomic status and trial arm. In the support arm, more deprived people lost less weight because they attended fewer sessions at the programme. In the advice arm, more deprived people who sought and paid for support for weight loss themselves lost more weight than more affluent people who sought support.

TRIAL REGISTRATION

This trial is registered with the ISRCTN registry, number ISRCTN26563137 . Date of registration: January 3, 2013; date of first participant recruited: June 4, 2014.

Determinants of a dietary pattern linked with greater metabolic risk and its tracking during adolescence

BACKGROUND

Although growing evidence suggests that dietary patterns associated with noncommunicable diseases in adulthood may develop early in life, when these are established, as well as their determinants, remains unclear.

METHODS

We examined determinants and tracking of a dietary pattern (DP) associated with metabolic risk and its key food groups among 860 adolescents in the Western Australian Pregnancy (Raine) Cohort study. Food intake was reported using a food frequency questionnaire (FFQ) at 14 and 17 years. Z-scores for an 'energy-dense, high-fat, low-fibre' DP were estimated by applying reduced rank regression at both ages. Tracking was based on the predictive value (PV) of remaining in the DPZ-score or food intake quartile at 14 and 17 years. Early-life exposures included: maternal age; maternal pre-pregnancy body mass index; parent smoking status during pregnancy; and parent socio-economic position (SEP) at 14 and 17 years. Associations between the DPZ-scores, early-life factors and SEP were analysed using regression analysis.

RESULTS

Dietary tracking was strongest among boys with high DPZ-scores, high intakes of processed meat, low-fibre bread, crisps and savoury snacks (PV > 1) and the lowest intakes of vegetables, fruit and legumes. Lower maternal education (β = 0.09, P = 0.002 at 14 years; β = 0.14, P < 0.001 at 17 years) and lower maternal age at birth (β = 0.09, P = 0.003 at 14 years; β = 0.11, P = 0.004 at 17 years) were positively associated with higher DPZ-scores.

CONCLUSIONS

An energy-dense, high-fat, low-fibre dietary pattern tracks more strongly among adolescent boys who have high scores for this pattern at 14 years of age. These findings highlight target foods and population subgroups for early interventions aiming to improve dietary behaviours.

Cognitive and behavioural strategies for self-directed weight loss: systematic review of qualitative studies

AIM

We conducted a systematic review of qualitative studies to examine the strategies people employ as part of self-directed weight loss attempts, map these to an existing behaviour change taxonomy and explore attitudes and beliefs surrounding these strategies.

METHODS

Seven electronic databases were searched in December 2015 for qualitative studies in overweight and obese adults attempting to lose weight through behaviour change. We were interested in strategies used by participants in self-directed efforts to lose weight. Two reviewers extracted data from included studies. Thematic and narrative synthesis techniques were used.

RESULTS

Thirty one studies, representing over 1,000 participants, were included. Quality of the included studies was mixed. The most commonly covered types of strategies were restrictions, self-monitoring, scheduling, professional support and weight management aids. With the exception of scheduling, for which participant experiences were predominantly positive, participants' attitudes and beliefs surrounding implementation of these groups of strategies were mixed. Two new groups of strategies were added to the existing taxonomy: reframing and self-experimentation.

CONCLUSIONS

This review demonstrates that at present, interventions targeting individuals engaged in self-management of weight do not necessarily reflect lived experiences of self-directed weight loss.

Recent trends in weight loss attempts: repeated cross-sectional analyses from the health survey for England

BACKGROUND

Public policies and clinical guidelines encourage people to achieve and maintain a healthy weight and societal culture, especially among women who tend to idealise thinness.

OBJECTIVES

To examine trends over time in the prevalence of weight loss attempts in England (1997-2013) and to investigate if the characteristics associated with attempts to lose weight have changed.

METHODS

Observational study using nationally representative data on adults ⩾18 years who participated in the Health Survey for England (HSE) in 1997 (n=8066), 1998 (n=14 733), 2002 (n=8803), 2012 (n=7132) and 2013 (n=7591), with self-reported attempts to lose weight, cardiovascular disease (CVD) events or medications and measured height, weight and blood pressure. Multivariable logistic regression was used to assess the association between weight loss attempts and survey year, socio-demographic variables and health status.

RESULTS

The age-standardised prevalence of weight loss attempts in the English population increased from 39% in 1997 to 47% in 2013. In 2013, 10% of those with BMI <22; 30% with BMI ⩾22 to <25; 53% with BMI ⩾25 to <30; and 76% with BMI ⩾30 were trying to lose weight. The odds of trying to lose weight increased linearly with each year: odds ratio (OR) 1.021 (95% confidence interval (CI) 1.018-1.024) and 1.024 (95% CI 1.008-1.039) after adjustment for changes in BMI and population characteristics. The biggest predictors of weight loss attempts were being in the overweight/obese categories: 5.42 (95% CI 5.05-5.81) and 12.68 (95% CI 11.52-13.96), respectively; and among women: 3.01 (95% CI 2.85-3.18). Having a BMI >25 and a CVD-related condition was associated with only a small increase in the odds of trying to lose weight. There was no evidence that these predictors changed over time.

CONCLUSIONS

More people are making weight loss attempts each year across all BMI categories. Having a health condition that would improve with weight loss was only very modestly associated with an increase in reported weight loss attempts, which reinforces data that suggests people's prime motivation to lose weight is unrelated to health.

Energy and nutrient intakes of young children in the UK: findings from the Gemini twin cohort

Data on the diets of young children in the UK are limited, despite growing evidence of the importance of early diet for long-term health. We used the largest contemporary dietary data set to describe the intake of 21-month-old children in the UK. Parents of 2336 children aged 21 months from the UK Gemini twin cohort completed 3-d diet diaries in 2008/2009. Family background information was obtained from questionnaires completed 8 months after birth. Mean total daily intakes of energy, macronutrients (g and %E) and micronutrients from food and beverages, including and excluding supplements, were derived. Comparisons with UK dietary reference values (DRV) were made using t tests and general linear regression models, respectively. Daily energy intake (kJ), protein (g) and most micronutrients exceeded DRV, except for vitamin D and Fe, where 96 or 84 % and 70 or 6 % of children did not achieve the reference nutrient intake or lower reference nutrient intake (LRNI), respectively, even with supplementation. These findings reflect similar observations in the smaller sample of children aged 18-36 months in the National Diet and Nutrition Survey. At a population level, young children in the UK are exceeding recommended daily intakes of energy and protein, potentially increasing their risk of obesity. The majority of children are not meeting the LRNI for vitamin D, largely reflecting inadequate use of the supplements recommended at this age. Parents may need more guidance on how to achieve healthy energy and nutrient intakes for young children.

Fruit, vegetable and vitamin C intakes and plasma vitamin C: cross-sectional associations with insulin resistance and glycaemia in 9-10 year-old children

AIM

To examine whether low circulating vitamin C concentrations and low fruit and vegetable intakes were associated with insulin resistance and other Type 2 diabetes risk markers in childhood.

METHODS

We conducted a cross-sectional, school-based study in 2025 UK children aged 9-10 years, predominantly of white European, South-Asian and black African origin. A 24-h dietary recall was used to assess fruit, vegetable and vitamin C intakes. Height, weight and fat mass were measured and a fasting blood sample collected to measure plasma vitamin C concentrations and Type 2 diabetes risk markers.

RESULTS

In analyses adjusting for confounding variables (including socio-economic status), a one interquartile range higher plasma vitamin C concentration (30.9 μmol/l) was associated with a 9.6% (95% CI 6.5, 12.6%) lower homeostatic model assessment of insulin resistance value, 0.8% (95% CI 0.4, 1.2%) lower fasting glucose, 4.5% (95% CI 3.2, 5.9%) lower urate and 2.2% (95% CI 0.9, 3.4%) higher HDL cholesterol. HbA1c concentration was 0.6% (95% CI 0.2, 1.0%) higher. Dietary fruit, vegetable and total vitamin C intakes were not associated with any Type 2 diabetes risk markers. Lower plasma vitamin C concentrations in South-Asian and black African-Caribbean children could partly explain their higher insulin resistance.

CONCLUSIONS

Lower plasma vitamin C concentrations are associated with insulin resistance and could partly explain ethnic differences in insulin resistance. Experimental studies are needed to establish whether increasing plasma vitamin C can help prevent Type 2 diabetes at an early stage.

Clinical effectiveness of very-low-energy diets in the management of weight loss: a systematic review and meta-analysis of randomized controlled trials

Guidelines suggest that very-low-energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain. Literature databases were searched from inception to November 2014. Randomized trials were included where the intervention included a VLED and the comparator was no intervention or an intervention that could be given in a general medical setting in adults that were overweight. Two reviewers characterized the population, intervention, control groups, outcomes and appraised quality. The primary outcome was weight change at 12 months from baseline. Compared with a behavioural programme alone, VLEDs combined with a behavioural programme achieved -3.9 kg [95% confidence interval (CI) -6.7 to -1.1] at 1 year. The difference at 24 months was -1.4 kg (95%CI -2.6 to -0.2) and at 38-60 months was -1.3 kg (95%CI -2.9 to 0.2). Nineteen per cent of the VLED group discontinued treatment prematurely compared with 20% of the comparator groups, relative risk 0.96 (0.56 to 1.66). One serious adverse event, hospitalization with cholecystitis, was reported in the VLED group and none in the comparator group. Very-low-energy diets with behavioural programmes achieve greater long-term weight loss than behavioural programmes alone, appear tolerable and lead to few adverse events suggesting they could be more widely used than current guidelines suggest.

Effectiveness of regular weighing, weight target setting and feedback by community midwives within routine antenatal care in preventing excessive gestational weight gain: randomised controlled trial

Background

Many pregnant women gain excess weight during pregnancy which increases the health risks to the mother and her baby. Interventions to prevent excess weight gain need to be given to the whole population to prevent excess weight gain. The aim of this study was to assess the effectiveness of a simple and brief intervention embedded withinroutine antenatal care to prevent excessive gestation weight gain.

Methods

Six hundred and ten pregnant women (between 10-14 weeks gestation), aged ≥18 years with a body mass index (BMI) ≥18.5 kg/m2, planned to receive community midwife led care or shared care at the time of recruitment are eligible to take part in the study. Women will be recruited from four maternity centres in England. Community midwives complete a short training module before delivering the intervention. In the intervention, midwives weigh women, set maximum weight limits for weight gain at each antenatal appointment and ask women to monitor their weight at home. Themaximum weight limit is adjusted by the midwife at each antenatal appointment if women have exceeded their maximum weight gain limit set at their previous appointment. The intervention will be compared with usual antenatal care. The primary outcome is the proportion of women per group who exceed the Institute of Medicine guidelines for gestational weight gain at 38 weeks of pregnancy according to their early pregnancy BMI category.

Discussion

The proposed trial will test a brief intervention comprising regular weighing, target setting and monitoring ofweight during pregnancy that can be delivered at scale as part of routine antenatal care. Using the professional expertise of community midwives, but without specialist training in weight management, the intervention will incur minimal additionalhealthcare costs, and if effective at reducing excess weight gain, is likely to be very cost effective.

Trial registration

Current controlled trials ISRCTN67427351. Date assigned 29/10/2014.

Feasibility and acceptability of regular weighing, setting weight gain limits and providing feedback by community midwives to prevent excess weight gain during pregnancy: randomised controlled trial and qualitative study

Background

Regular weighing in pregnant women is not currently recommended in many countries but has been suggested to prevent excessive gestational weight gain. This study aimed to establish the feasibility and acceptability of incorporating regular weighing, setting maximum weight gain targets and feedback by community midwives.

Methods

Low risk pregnant women cared for by eight community midwives were randomised to usual care or usual care plus the intervention at 10–14 weeks of pregnancy. The intervention involved community midwives weighing and plotting weight on a weight gain chart, setting weight gain limit targets, giving brief feedback at each antenatal appointment and encouraging women to weigh themselves weekly between antenatal appointments. Women and midwives were interviewed about their views of the intervention. The focus of the study was on process evaluation.

Results

Community midwives referred 123 women and 115 were scheduled for their dating scan within the study period. Of these, 84/115 were approached at their dating scan and 76/84 (90.5 %) randomised. Data showed a modest difference favouring the intervention group in the percentage of women gaining excessive gestational weight (23.5 % versus 29.4 %). The intervention group consistently reported smaller increases in depression and anxiety scores throughout pregnancy compared with usual care. Most women commented the intervention was useful in encouraging them to think about their weight and believed it should be part of routine antenatal care. Community midwives felt the intervention could be implemented within routine care without adding substantially to consultation length, thus not perceived as adding substantially to their workload.

Conclusions

The intervention was feasible and acceptable to pregnant women and community midwives and was readily implemented in routine care.

Trial registration

ISRCTN81605162

Identification of a dietary pattern associated with greater cardiometabolic risk in adolescence

BACKGROUND AND AIMS

Energy dense, high fat, low fibre diets may contribute to obesity in young people, however their relationships with other cardiometabolic risk factors are unclear. We examined associations between an 'energy-dense, high-fat and low-fibre' dietary pattern (DP) and cardiometabolic risk factors, and the tracking of this DP in adolescence.

METHODS AND RESULTS

Data was sourced from participants in the Western Australian Pregnancy (Raine) Cohort Study. At 14 and 17 y, dietary intake, anthropometric and biochemical data were measured and z-scores for an 'energy dense, high fat and low fibre' DP were estimated using reduced rank regression (RRR). Associations between DP z-scores and cardiometabolic risk factors were examined using regression models. Tracking of DP z-scores was assessed using Pearson's correlation coefficient. A 1 SD unit increase in DP z-score between 14 and 17 y was associated with a 20% greater odds of high metabolic risk (95% CI: 1.01, 1.41) and a 0.04 mmol/L higher fasting glucose in boys (95% CI: 0.01, 0.08); a 28% greater odds of a high-waist circumference (95% CI: 1.00, 1.63) in girls. An increase of 3% and 4% was observed for insulin and HOMA (95% CI: 1%, 7%), respectively, in boys and girls, for every 1 SD increase in DP z-score and independently of BMI. The DP showed moderate tracking between 14 and 17 y of age (r = 0.51 for boys, r = 0.45 for girls).

CONCLUSION

An 'energy dense, high fat, low fibre' DP is positively associated with cardiometabolic risk factors and tends to persist throughout adolescence.

Personal and social norms for food portion sizes in lean and obese adults

Background

Portion size is an important component of dietary advice for weight control, but little is known about what portion sizes people consider “normal”. This study determined the effect of BMI, gender, dietary restraint, and liking of the food on personal and social portion size norms for a range of foods, and the degree of certainty over the norms.

Methods

30 lean (BMI 20-25kg/m²) and 30 obese (BMI 30-35kg/m²) men and women (aged 18-60years) viewed 17 different portion sizes of 12 foods on a computer screen on two occasions a week apart. Participants responded ‘more’ or ‘less’ to each photograph reflecting personal portion size preference or perceived portion sizes of others. Personal and social norms for portion sizes of each food were determined using the method of constant stimuli giving a sigmoidal curve of the probability of answering ‘less’ over a range of portion sizes. The slope of the sigmoid at the norm gave a measure of certainty about the norm. Regression models were used to examine the effect of BMI, gender, dietary restraint and liking of the food on personal norms, social norms, the relationship between norms, and the slopes.

Results

Personal norms were significantly larger in the obese (p=0.026), men (p<0.001), those with lower dietary restraint (p<0.001), and those with higher liking for the food (p<0.001). Social norms were larger for women (p=0.012). The slopes at the norms were 30% shallower in the obese and in men (p<0.001).

Conclusion

Larger personal norms for portion size among the obese, men, those with lower dietary restraint, and those with higher liking for a food imply greater consumption, which may undermine weight control. Shallower slopes for norms in the obese and in men may imply less clearly defined habitual portion sizes.

Plasma free fatty acids do not provide the link between obesity and insulin resistance or β-cell dysfunction: results of the Reading, Imperial, Surrey, Cambridge, Kings (RISCK) study

AIMS

To investigate the relationship between adiposity and plasma free fatty acid levels and the influence of total plasma free fatty acid level on insulin sensitivity and β-cell function.

METHODS

An insulin sensitivity index, acute insulin response to glucose and a disposition index, derived from i.v. glucose tolerance minimal model analysis and total fasting plasma free fatty acid levels were available for 533 participants in the Reading, Imperial, Surrey, Cambridge, Kings study. Bivariate correlations were made between insulin sensitivity index, acute insulin response to glucose and disposition index and both adiposity measures (BMI, waist circumference and body fat mass) and total plasma free fatty acid levels. Multivariate linear regression analysis was performed, controlling for age, sex, ethnicity and adiposity.

RESULTS

After adjustment, all adiposity measures were inversely associated with insulin sensitivity index (BMI: β = -0.357; waist circumference: β = -0.380; body fat mass: β = -0.375) and disposition index (BMI: β = -0.215; waist circumference: β = -0.248; body fat mass: β = -0.221) and positively associated with acute insulin response to glucose [BMI: β = 0.200; waist circumference: β = 0.195; body fat mass β = 0.209 (P values <0.001)]. Adiposity explained 13, 4 and 5% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively. After adjustment, no adiposity measure was associated with free fatty acid level, but total plasma free fatty acid level was inversely associated with insulin sensitivity index (β = -0.133), acute insulin response to glucose (β = -0.148) and disposition index [β = -0.218 (P values <0.01)]. Plasma free fatty acid concentration accounted for 1.5, 2 and 4% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively.

CONCLUSIONS

Plasma free fatty acid levels have a modest negative association with insulin sensitivity, β-cell secretion and disposition index but no association with adiposity measures. It is unlikely that plasma free fatty acids are the primary mediators of obesity-related insulin resistance or β-cell dysfunction.

Behavioural weight management programmes for adults assessed by trials conducted in everyday contexts: systematic review and meta-analysis

This systematic review and meta-analysis of effectiveness trials comparing multicomponent behavioural weight management programmes with controls in overweight and obese adults set out to determine the effectiveness of these interventions implemented in routine practice. To be included, interventions must have been multicomponent, delivered by the therapists who would deliver the intervention in routine practice and in that same context, and must be widely available or feasible to implement with little additional infrastructure or staffing. Searches of electronic databases were conducted, and augmented by screening reference lists and contacting experts (November 2012). Data were extracted by two reviewers, with mean difference between intervention and control for 12-month change in weight, blood pressure, lipids and glucose calculated using baseline observation carried forward. Data were also extracted on adverse events, quality of life and mood measures. Although there were many published efficacy trials, only eight effectiveness trials met the inclusion criteria. Pooled results from five study arms providing access to commercial weight management programmes detected significant weight loss at 12 months (mean difference -2.22 kg, 95% confidence interval [CI] -2.90 to -1.54). Results from two arms of a study testing a commercial programme providing meal replacements also detected significant weight loss (mean difference -6.83 kg, 95% CI -8.39 to -5.26). In contrast, pooled results from five interventions delivered by primary care teams showed no evidence of an effect on weight (mean difference -0.45 kg, 95% CI -1.34 to 0.43). One study testing an interactive web-based intervention detected a significant effect in favour of the intervention at 12 months, but the study was judged to be at high risk of bias and the effect did not persist at 18 months. Few studies reported other outcomes, limiting comparisons between interventions. Few trials have examined the effectiveness of behavioural weight loss programmes delivered in everyday contexts. These trials suggest that commercial interventions delivered in the community are effective for achieving weight loss. There is no evidence that interventions delivered within primary care settings by generalist primary care teams trained in weight management achieve meaningful weight loss.

Skeletal muscle mass reference curves for children and adolescents

BACKGROUND

Skeletal muscle is key to motor development and represents a major metabolic end organ that aids glycaemic regulation.

OBJECTIVES

To create gender-specific reference curves for fat-free mass (FFM) and appendicular (limb) skeletal muscle mass (SMMa) in children and adolescents. To examine the muscle-to-fat ratio in relation to body mass index (BMI) for age and gender.

METHODS

Body composition was measured by segmental bioelectrical impedance (BIA, Tanita BC418) in 1985 Caucasian children aged 5-18.8 years. Skeletal muscle mass data from the four limbs were used to derive smoothed centile curves and the muscle-to-fat ratio.

RESULTS

The centile curves illustrate the developmental patterns of %FFM and SMMa. While the %FFM curves differ markedly between boys and girls, the SMMa (kg), %SMMa and %SMMa/FFM show some similarities in shape and variance, together with some gender-specific characteristics. Existing BMI curves do not reveal these gender differences. Muscle-to-fat ratio showed a very wide range with means differing between boys and girls and across fifths of BMI z-score.

CONCLUSIONS

BIA assessment of %FFM and SMMa represents a significant advance in nutritional assessment since these body composition components are associated with metabolic health. Muscle-to-fat ratio has the potential to provide a better index of future metabolic health.

Effect of behavioural techniques and delivery mode on effectiveness of weight management: systematic review, meta-analysis and meta-regression

A systematic review, meta-analysis and meta-regression were conducted to evaluate the effectiveness of behavioural weight management programmes and examine how programme characteristics affect mean weight loss. Randomized controlled trials of multicomponent behavioural weight management programmes in overweight and obese adults were included. References were obtained through systematic searches of electronic databases (conducted November 2012), screening reference lists and contacting experts. Two reviewers extracted data and evaluated risk of bias. Thirty-seven studies, representing over 16,000 participants, were included. The pooled mean difference in weight loss at 12 months was -2.8 kg (95% confidence interval [CI] -3.6 to -2.1, P < 0.001). I(2) indicated that 93% of the variability in outcome was due to differences in programme effectiveness. Meta-analysis showed no evidence that supervised physical activity sessions (mean difference 1.1 kg, 95% CI -2.65 to 4.79, P = 0.08), more frequent contact (mean difference -0.3 kg, 95% CI -0.7 to 0.2, P = 0.25) or in-person contact (mean difference 0.0 kg, 95% CI -1.8 to 1.8, P = 0.06) were related to programme effectiveness at 12 months. In meta-regression, calorie counting (-3.3 kg, 95% CI -4.6 to -2.0, P = 0.027), contact with a dietitian (-1.5 kg, 95% CI -2.9 to -0.2, P < 0.001) and use of behaviour change techniques that compare participants' behaviour with others (-1.5 kg, 95% CI -2.9 to -0.1, P = 0.032) were associated with greater weight loss. There was no evidence that other programme characteristics were associated with programme effectiveness. Most but not all behavioural weight management programmes are effective. Programmes that support participants to count calories or include a dietitian may be more effective, but the programme characteristics explaining success are mainly unknown.

Changes in physical activity during a weight loss intervention and follow-up: a randomized controlled trial

Physical activity is an important component in weight loss treatment and weight maintenance. We evaluated the physical activity component of two weight loss programmes, either standard care (SC) as defined by national guidelines, or a commercial programme (CP; Weight Watchers) over the period of weight loss and follow-up. 772 adults (mean body mass index: 31.4 ± 2.6 kg m(-2)) were recruited by primary care practices in Australia, the United Kingdom, and Germany, and randomly assigned to 12 months SC, or the CP. They were then followed up at 24 months. Change in physical activity levels were assessed by the International Physical Activity Questionnaire (IPAQ)-short form, and pedometer recordings. Both groups reported increases in physical activity using the IPAQ from baseline to 12 months and 24 months (within groups P < 0.0001) and in pedometer steps from baseline to 12 months only (within groups P < 0.0001). Differences between groups with both methods of assessment were not significant. There was a significant difference in weight loss between the groups at 12 months favouring the CP group; however, this statistical difference was not maintained at 24 months. In conclusion, despite similar increases in reported activity, there were significant differences in weight loss and regain between groups. Therefore, greater weight loss seen with the CP is unlikely to be due to increases in physical activity. Trends in pedometer steps mirrored changes in weight over time more closely than the IPAQ; however, both assessment tools have limitations. Better activity assessment measures are needed to more accurately gauge changes in physical activity during weight loss interventions.

The challenge of a 2-year follow-up after intervention for weight loss in primary care

BACKGROUND

Many weight loss programmes show short-term success, but long-term data in larger studies are scarce, especially in community settings. Attrition is common and complicates the interpretation of long-term outcomes.

OBJECTIVE

To investigate 2-year outcomes and explore issues of attrition and missing data.

SUBJECTS

A total of 772 overweight and obese adults recruited by primary care practices in Australia, Germany and the UK and randomised to a 12-month weight loss intervention delivered in a commercial programme (CP) or in standard care (SC).

MEASUREMENT

Weight change from 0-24 and 12-24 months including measured weights only and measured and self-reported weights, using last observation carried forward (LOCF), baseline observation carried forward (BOCF), completers-only and missing-at-random (MAR) analyses.

RESULTS

A total of 203 participants completed the 24-month visit. Using measured weights only, there was a trend for greater 24-month weight loss in CP than in SC, but the difference was only statistically significant in the LOCF and BOCF analyses: LOCF: -4.14 vs -1.99 kg, difference adjusted for centre -2.08 kg, P<0.001; BOCF: -1.33 vs -0.74 kg, adjusted difference -0.60 kg, P=0.032; completers: -4.76 vs -2.99 kg, adjusted difference -1.53 kg, P=0.113; missing at random: -3.00 vs -1.94 kg, adjusted difference -1.04 kg, P=0.150. Both groups gained weight from 12-24 months and weight regain was significantly (P<0.001) greater for CP than for SC in all analysis approaches. Inclusion of self-reported weights from a further 138 participants did not change the interpretation of the findings.

CONCLUSION

Initial weight loss was poorly maintained during the no-intervention follow-up, but both groups did have lower weight over the 24 months. Attrition was high in both groups, and assumptions about missing data had considerable impact on the magnitude and statistical significance of treatment effects. It is vital that trials on weight loss interventions consider the plausibility of these differences in an analytical approach when interpreting research findings and comparing data between studies.

The evolution of policy and actions to tackle obesity in England

Tackling obesity has been a policy priority in England for more than 20 years. Two formal government strategies on obesity in 2008 and 2011 drew together a range of actions and developed new initiatives to fill perceived gaps. Today, a wide range of policies are in place, including support for breastfeeding and healthy weaning practices, nutritional standards in schools, restrictions on marketing foods high in fat, sugar and salt to children, schemes to boost participation in sport, active travel plans, and weight management services. Data from annual surveys show that the rate of increase in obesity has attenuated in recent years, but has not yet been reversed. This paper considers the actions taken and what is known about the impact of individual policies and the overarching strategy to tackle obesity in England.

Characterizing the EPODE logic model: unravelling the past and informing the future

EPODE ('Ensemble Prévenons l'Obésité De Enfants' or 'Together let's Prevent Childhood Obesity') is a large-scale, centrally coordinated, capacity-building approach for communities to implement effective and sustainable strategies to prevent childhood obesity. Since 2004, EPODE has been implemented in over 500 communities in six countries. Although based on emergent practice and scientific knowledge, EPODE, as many community programs, lacks a logic model depicting key elements of the approach. The objective of this study is to gain insight in the dynamics and key elements of EPODE and to represent these in a schematic logic model. EPODE's process manuals and documents were collected and interviews were held with professionals involved in the planning and delivery of EPODE. Retrieved data were coded, themed and placed in a four-level logic model. With input from international experts, this model was scaled down to a concise logic model covering four critical components: political commitment, public and private partnerships, social marketing and evaluation. The EPODE logic model presented here can be used as a reference for future and follow-up research; to support future implementation of EPODE in communities; as a tool in the engagement of stakeholders; and to guide the construction of a locally tailored evaluation plan.

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

Incidence and recognition of malnutrition in hospital J. P. McWhirter and C. R. Pennington BMJ 1994; 308: 945-948

This paper describes a prospective study to determine the incidence of malnutrition among patients on admission to an acute teaching hospital, to monitor their changes in nutritional status during stay and to determine awareness of nutrition in different clinical units. Nutritional status was assessed in 500 patients admitted to hospital: 100 each from general surgery, general medicine, respiratory medicine, orthopaedic surgery and medicine for the elderly. The main outcome measures were weight, height, triceps skinfold thickness, mid arm circumference, mid arm muscle circumference and grip strength. Patients were studied on admission and discharge and case notes reviewed for information about nutritional status. On admission 200 out of 500 patients were considered undernourished (BMI < 20). Of these only 96 had any nutritional information documented in the notes. 34% of patients were overweight (BMI > 25). The 112 patients reassessed on discharge had a mean weight loss of 5.4% with the greatest weight loss in those initially most malnourished. The 10 patients who were referred for nutritional support (3 for parenteral nutrition, 7 for enteral nutrition) showed a mean weight gain of 7.9%.

EPODE approach for childhood obesity prevention: methods, progress and international development

Childhood obesity is a complex issue and needs multi-stakeholder involvement at all levels to foster healthier lifestyles in a sustainable way. 'Ensemble Prévenons l'Obésité Des Enfants' (EPODE, Together Let's Prevent Childhood Obesity) is a large-scale, coordinated, capacity-building approach for communities to implement effective and sustainable strategies to prevent childhood obesity. This paper describes EPODE methodology and its objective of preventing childhood obesity. At a central level, a coordination team, using social marketing and organizational techniques, trains and coaches a local project manager nominated in each EPODE community by the local authorities. The local project manager is also provided with tools to mobilize local stakeholders through a local steering committee and local networks. The added value of the methodology is to mobilize stakeholders at all levels across the public and the private sectors. Its critical components include political commitment, sustainable resources, support services and a strong scientific input--drawing on the evidence-base--together with evaluation of the programme. Since 2004, EPODE methodology has been implemented in more than 500 communities in six countries. Community-based interventions are integral to childhood obesity prevention. EPODE provides a valuable model to address this challenge.

Genetic predisposition influences plasma lipids of participants on habitual diet, but not the response to reductions in dietary intake of saturated fatty acids

OBJECTIVE

SNPs identified from genome-wide association studies associate with lipid risk markers of cardiovascular disease. This study investigated whether these SNPs altered the plasma lipid response to diet in the 'RISCK' study cohort.

METHODS

Participants (n=490) from a dietary intervention to lower saturated fat by replacement with carbohydrate or monounsaturated fat, were genotyped for 39 lipid-associated SNPs. The association of each individual SNP, and of the SNPs combined (using genetic predisposition scores), with plasma lipid concentrations was assessed at baseline, and on change in response to 24 weeks on diets.

RESULTS

The associations between SNPs and lipid concentrations were directionally consistent with previous findings. The genetic predisposition scores were associated with higher baseline concentrations of plasma total (P=0.02) and LDL (P=0.002) cholesterol, triglycerides (P=0.001) and apolipoprotein B (P=0.004), and with lower baseline concentrations of HDL cholesterol (P<0.001) and apolipoprotein A-I (P<0.001). None of the SNPs showed significant association with the reduction of plasma lipids in response to the dietary interventions and there was no evidence of diet-gene interactions.

CONCLUSION

Results from this exploratory study have shown that increased genetic predisposition was associated with an unfavourable plasma lipid profile at baseline, but did not influence the improvement in lipid profiles by the low-saturated-fat diets.

Dietary strategy to manipulate ad libitum macronutrient intake, and glycaemic index, across eight European countries in the Diogenes Study

The aim of this study was to describe the development and implementation of a multifaceted, low-fat, weight-loss strategy for a Pan-European randomized controlled dietary intervention study, Diogenes. There were 891 families with at least one overweight/obese parent who underwent screening. Eligible, overweight/obese adults followed an 8-week weight-loss phase with a fixed low-energy diet (800 kcal). On attaining weight loss of > or = 8%, families were randomized to a 6- or 12-month low-fat (25-30%E) diet either based on national dietary guidelines or one of four interventions: low protein (LP)/low glycaemic index (LGI), LP/high GI (HGI), high protein (HP)/LGI and HP/HGI. The impact of each diet in preventing weight (re)gain was tested. A points-based system was used to manipulate dietary protein and carbohydrate. Manipulating carbohydrate composition involved substituting foods with a relatively high or low GI. A questionnaire was designed and completed by study investigators, providing feedback on the dietary intervention methods used to inform future interventions. The points system allowed macronutrient manipulations without compromising dietary flexibility or enforcing energy restrictions. Reported centre/participant differences in the ease of implementing the intervention may reflect dietary diversity and personal preferences for specific weight-management strategies. The points system provides a useful starting point for designing improved experimental paradigms for the manipulation of dietary intake in future trials.

Developing a methodology for assigning glycaemic index values to foods consumed across Europe

There is growing evidence that the glycaemic index (GI) of the diet is important with respect to body weight and metabolic disease risk. However, research is limited by the paucity of GI values for commonly consumed carbohydrate-rich foods in European countries. A new methodology has been developed for consistent assignment of GI values to foods across five European databases used in the Diogenes intervention study. GI values were assigned according to five decreasing levels of confidence (1) Measured values for specific foods; (2) Published values from published sources; (3) Equivalent values where published values for similar foods existed; (4) Estimated values assigned as one of three values representing low/medium/high GI ranges and (5) Nominal values assigned as 70, where no other value could be assigned with sufficient confidence. GI values were assigned to 5105 foods. In food records collected at baseline, the contribution to carbohydrate intake of foods assigned levels 1-2 ranged from 16% to 43% depending on country, and this increased to 53-81% including level 3 foods. The degree of confidence to assigned GI values differed across Europe. This standardized approach of assigning GI values will be made available to other researchers to facilitate further investigation into the effects of dietary GI on health.

Reflections from a systematic review of dietary energy density and weight gain: is the inclusion of drinks valid?

The association between dietary energy density, increased energy intake and weight gain is supported by experimental evidence, but confirmation of an effect in free-living humans is limited. Experimental evidence supports a role of energy density in obesity through changes in food composition, not drinks consumption. The inclusion of drinks in the calculation creates a variable of questionable validity and has a substantive impact on the estimated energy density of the diet. We posit, based on the experimental evidence, that calculating the energy density of diets by excluding drinks and including calories from drinks as a covariate in the analysis is the most valid and reliable method of testing the relationship between energy density and weight gain in free-living humans. We demonstrate, by systematically reviewing existing observational studies of dietary energy density and weight gain in free-living humans, how current variation in the method for calculating energy density hampers the interpretation of these data. Reaching an a priori decision on the appropriate methodology will reduce the error caused by multiple comparisons and facilitate meaningful interpretation of epidemiological evidence to inform the development of effective obesity prevention strategies.

Assessment of changes in total body water in patients undergoing renal dialysis using bioelectrical impedance analysis

This study aimed to assess whether changes in fluid can be accurately predicted from the change in whole-body impedance with an appropriate correction for the conductor length (i.e. height). Eight studies to measure changes in impedance were performed on six patients during dialysis. The measured loss of fluid from the beginning to the end of dialysis (1174+/-706ml) agreed well with the change in body weight (1188+/-768kg). The regression lines of the plot of change in height(2)/impedance versus loss of fluid for each subject had correlation coefficients ranging from 0.880-0.999, but there was a four-fold variation in the slopes of the different curves. The mean +/- SD change in height(2)/impedance during the removal of 0.5, 1 and 2l of water was 1.75+/-0.96, 3.41+/-1.55 and 6.72+/-2.91 m(2)/ohms respectively. The total change in body water, calculated by a variety of prediction equations, overestimated the loss of fluid by a mean of between 86 and 100%. The lack of a fixed relationship between changes in impedance and changes in body water precludes the use of the impedance technique as a means of accurately assessing small fluid changes in this patient group.

A prospective analysis of dietary energy density at age 5 and 7 years and fatness at 9 years among UK children

OBJECTIVE

To analyse whether high dietary energy density (DED) is associated with increased fat mass and risk of excess adiposity in free-living children.

DESIGN

Longitudinal, observational cohort study.

SUBJECTS

Six hundred and eighty-two healthy children from the Avon Longitudinal Study of Parents and Children.

MEASUREMENTS

Diet was assessed at age 5 and 7 years using 3-day diet diaries, and DED (kJ g(-1)) was calculated excluding drinks. Fat mass was estimated at age 9 years using Dual-Energy X-ray Absorptiometry. To adjust for body size, fat mass index (FMI) was calculated by dividing fat mass (kg) by height (m(5.8)). Excess adiposity was defined as the top quintile of logFMI.

RESULTS

Mean DED at age 5 years was higher among children with excess adiposity at age 9 years compared to the remaining sample (8.8+/-0.16 vs 8.5+/-0.07 kJ g(-1)), but there was no evidence of an association with excess adiposity at age 9 years (odds ratio (OR)=1.14, 95% confidence interval (CI) 0.90-1.44) after controlling for potential confounders. Mean DED at age 7 years was higher among children with excess adiposity compared to the remaining sample (9.1+/-0.12 vs 8.8+/-0.06 kJ g(-1)) and a 1 kJ g(-1) rise in DED increased the odds of excess adiposity at 9 years by 36% (OR=1.36, 95% CI 1.09-1.69) after controlling for potential confounders.

CONCLUSION

Higher DED at age 7 years, but not age 5 years, is a risk factor for excess adiposity at age 9 years, perhaps reflecting deterioration in the ability to compensate for extra calories in an energy-dense diet. DED tracks strongly from age 5 to 7 years suggesting intervention to alter dietary habits need to commence at younger ages to prevent the formation of preferences for energy dense foods.

Whole grains and adiposity: little association among British adults

OBJECTIVES

To examine associations of whole-grain intake with body weight and adiposity in two nationally representative samples of British adults.

SUBJECTS/METHODS

A total of 2064 adults aged 16-64 years in 1986-1987, 1599 adults aged 19-64 years in 2000-2001. Whole-grain intake (g day(-1) and 16-g amounts) was estimated from consumption of all foods with >or=10, >or=25 or >or=51% whole-grain content, using 7-day weighed dietary records. Body weight, body mass index (BMI) and, in 2000-2001, waist circumference (WC) were measured. BMI and WC were considered as continuous and categorical variables. For each survey, associations of whole-grain intake with body weight and anthropometric indices were examined in men and women separately, before and after adjustment for age, occupational social class, smoking habit, region, season and, in 2000-2001, misreporting.

RESULTS

In 1986-1987, whole-grain intake was inversely associated with percentage of men classified using BMI as obese (P=0.008, trend), independent of other factors. However, intake was not associated with body weight or prevalence of overweight. No corresponding associations were observed among women. In 2000-2001, whole-grain intake was not associated with body weight, BMI or WC.

CONCLUSIONS

Two national surveys of British adults, with detailed quantitative estimates of whole-grain intake, provide little evidence of an association of whole-grain intake with body weight or measures of adiposity.

Determination of the glycaemic index of various staple carbohydrate-rich foods in the UK diet

OBJECTIVE

To determine the glycaemic index (GI) of various staple carbohydrate-rich foods in the UK diet, and to consider the factors influencing the GI of foods.

DESIGN

Subjects were served with 25 or 50 g portions of glucose on three occasions, followed by a selection of test foods providing an equal amount of available carbohydrate, in random order. Each test food was consumed by 10 subjects. Capillary blood glucose levels were measured in the fasted state and over the 120 min following commencement of consumption of the foods.

SETTING

The study was carried out in a research institute (MRC Human Nutrition Research, Cambridge, UK).

SUBJECTS

Forty-two healthy adult volunteers were studied.

METHODS

The GI values of 33 foods were measured according to the WHO/FAO recommended methodology. These foods included various breads, breakfast cereals, pasta, rice and potatoes, all of which were commercially available in the UK.

CONCLUSIONS

The results illustrate a number of factors which are important in influencing the GI of a food, highlighting the importance of measuring the GI of a food, rather than assuming a previously published value for a similar food. This is useful both to researchers analysing dietary surveys or planning intervention studies, and also to health professionals advising individuals on their diets.

Whole-grain intake of British young people aged 4–18 years

Inverse associations between whole-grain food consumption and risk of CVD, some cancers and type 2 diabetes have been reported. However, there are few reports of whole-grain intake, particularly among young people. The objective of the present study was to estimate whole-grain intake in a nationally representative sample of young people aged 4–18 years living in Great Britain. Whole-grain intake was estimated using 7d weighed dietary records from 1583 young people who participated in the cross-sectional National Diet and Nutrition Survey in 1997. Whole-grain intake was quantified from the consumption of all foods containing ≥10% whole-grain content. Median whole-grain intake was 7g/d (interquartile range 0–19g/d), with a corresponding mean of 13 (sd18) g/d. Intake was significantly lower among young people whose head of household had a manual occupation, but did not differ significantly by sex, age, region or season. There was no whole-grain intake for 27% of participants. The percentages for less than one and less than three 16g amounts of whole-grain intake per d were 70 and 94, respectively, while corresponding percentages based on 20g amounts were 76 and 97. Foods with <51% whole-grain content provided 28% of whole-grain intake overall, with a higher percentage in older adolescents. The main sources of whole-grain intake were breakfast cereals (56%) and bread (25%). The present study provides the first quantification of absolute whole-grain intake from all significant food sources in any representative age group in the UK. Although there is some debate regarding the quantity of whole grains required for good health, whole-grain intake among British young people is low.

Ethnic differences in the association between body mass index and impedance index (Ht2/Z) in adult women and men using a leg-to-leg bioimpedance method

BACKGROUND

Ethnic differences in the association between body mass index (BMI) and body fat suggest that body composition varies across ethnic groups.

OBJECTIVE

To investigate the association between impedance index - a measure of tissue resistivity - and BMI in adults of different ethnic groups (Asian Indians, West Africans and White Caucasians) living in their native countries.

METHODS

Male (n=329) and female (n=277) adult subjects (18-50 years) living in urban areas in the UK, The Gambia and Pakistan were studied. Body weight and height were measured and BMI calculated. The same leg-to-leg bioimpedance instrument was used in each study and impedance index (height(2) (cm)/impedance (Omega)) used as measure of tissue resistivity.

RESULTS

In women, Asian Indians and West Africans had a significantly greater increase in impedance index per unit increase in BMI compared with white Caucasians (P<0.001). In men, Asian Indians had a significantly lower impedance index compared with West Africans and white Caucasians (P<0.001).

CONCLUSION

Different ethnic groups may have different tissue resistivity for the same BMI indicative of systematic differences in body composition.

The impact of long chain n-3 polyunsaturated fatty acid supplementation on inflammation, insulin sensitivity and CVD risk in a group of overweight women with an inflammatory phenotype

BACKGROUND

Inflammation is strongly related to obesity and the risk of cardiovascular disease (CVD). The metabolic benefits of long chain (LC) n-3 polyunsaturated fatty acid (PUFA) may be attributable to its anti-inflammatory properties.

OBJECTIVE

To investigate whether an individual's habitual inflammatory status influences the impact of a LC n-3 PUFA intervention on CVD risk.

DESIGN

The study was a randomized crossover design. Subjects received LC n-3 PUFA capsules or a placebo for 12 weeks, with 4-week washout between phases. Thirty women, in the top and bottom tertiles of baseline sialic acid concentration, formed raised inflammatory status (top, n = 12) and reference (bottom, n = 18) groups. Baseline data were analysed using one-way anova, differences between treatment phases were calculated at each timepoint and analysed using a random effects model.

RESULTS

At baseline, the raised inflammatory status group had significantly higher body mass index and area under the curve (AUC) insulin than the reference group. With LC n-3 PUFA supplementation, both groups showed significantly higher plasma eicosapentaenoic acid and docosahexaenoic acid at 4 and 12 weeks (p < 0.001), and lower triacylglycerols (4 weeks p < 0.01 and 12 weeks p < 0.05). The difference in AUC insulin between the two treatment phases at 12 weeks was significantly greater in the raised inflammatory status group compared to the reference group (p < 0.05). Inflammatory markers were significantly lower after 12 weeks LC n-3 PUFA supplementation compared to baseline (C-reactive protein p < 0.05 and interleukin-6 p < 0.01), but there was no significant group effect.

CONCLUSIONS

Habitual inflammatory status influences the impact of LC n-3 PUFA supplementation, but it is not clear whether the effect of LC n-3 PUFA on AUC insulin is mediated through inflammatory mechanisms.

Frequent feeding delays the gastric emptying of a subsequent meal

To assess the suitability of the 13C-octanoic acid breath test for measuring gastric emptying in circumstances other than the post-absorptive state, a preliminary study was performed where 6 hourly spaced isoenergetic meals preceded the determination of gastric emptying of a subsequent 2 MJ meal. Emptying was measured in three individuals on four separate occasions, with a reproducibility of 8%. A crossover study was then conducted to test the hypothesis that meal frequency can modulate the gastric emptying of a subsequent meal, with the potential to influence appetite regulation. Sixteen subjects were fed to energy balance, receiving food either as 2 isoenergetic meals 3 h apart or 6 isoenergetic meals fed hourly. Gastric emptying of a subsequent 2 MJ meal was investigated. Visual analogue scales were used throughout to assess appetite. The maximum rate of gastric emptying was unchanged but the onset of emptying was delayed by the more frequent feeding pattern. There was no significant difference in subjective appetite before or after the test meal. In conclusion, short-term increases in feeding frequency delayed the gastric emptying of a subsequent meal, but significant effects on post-meal appetite could not be demonstrated.

Validity of the leg-to-leg bioimpedance to estimate changes in body fat during weight loss and regain in overweight women: a comparison with multi-compartment models

OBJECTIVES

To investigate changes in body composition and the validity of the leg-to-leg bioimpedance (LTL) method to measure body fat during active weight loss (WL) and weight regain (WR).

DESIGN

Longitudinal, 12-week weight loss intervention (3.3-3.8 MJ/day) and subsequent follow-up at 1 year.

SUBJECTS

Fifty-eight adult women aged between 24 and 65 years (mean age: 46.8+/-8.9 years) and with a body mass index (BMI) > or =25 kg/m(2) (mean BMI: 31.6+/-2.5 kg/m(2), range=26.0-48.2 kg/m(2)) participated in the study.

MEASUREMENTS

Fat mass (FM) was measured at baseline, 12 weeks, 24 weeks and 52 weeks using three- and four-compartment (4-C) models, air displacement plethysmography (ADP), deuterium dilution - total body water (TBW), dual-energy X-ray absorptiometry (DXA), skinfold thickness (SFT), tetrapolar bioelectrical impedance analysis (T-BIA) and LTL.

RESULTS

At the end of the weight loss programme, subjects lost 9.9+/-3.5 kg weight (P<0.001) and 7.6+/-0.5 kg fat (P<0.001) but after 1 year they had regained 4.9+/-3.7 kg of weight and 3.7+/-2.9 kg of fat. The 4-C model showed that FM and TBW accounted for 76.2 and 23.6% of the loss in body mass and 81.8 and 17.7% of the tissue accrued during weight regain, respectively. The estimate of body fat change by LTL relative to multi-compartment models (WL(bias+/-2s.d.)=0.51+/-3.26 kg; WR(bias+/-2s.d.)=-0.25+/-2.30 kg) was similar to ADP, DXA and TBW in both phases but it was better than T-BIA (WL(bias+/-2s.d.)=0.17+/-7.90 kg; WR(bias+/-2s.d.)=-0.29+/-7.59 kg) and skinfold thickness (WL(bias+/-2s.d.)=2.68+/-6.68 kg; WR(bias+/-2s.d.)=-0.84+/-3.80 kg).

CONCLUSIONS

Weight loss and regain were associated with minimal changes in lean tissue as measured using multi-compartment models. The LTL system is a useful method to measure body composition changes during clinical weight management programmes.

Additive benefits of long-chain n-3 polyunsaturated fatty acids and weight-loss in the management of cardiovascular disease risk in overweight hyperinsulinaemic women

BACKGROUND

Obesity, inflammation, insulin resistance and cardiovascular disease (CVD) risk are inter-related. Both weight-loss and long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) are independently known to reduce metabolic risk, but the combined effects are unclear.

OBJECTIVE

This study examines whether addition of LC n-3 PUFA to a low fat/high carbohydrate weight-loss programme results in greater improvements in inflammation, insulin sensitivity and CVD risk, than weight-loss alone.

DESIGN

One hundred and sixteen overweight insulin-resistant women entered a 24-week randomised intervention study. Thirty-nine women were randomised to a weight-loss programme, with LC n-3 PUFA (WLFO), 38 to a weight-loss programme with placebo oil (WLPO), and 39 to receive placebo oil, with no weight-loss programme (control).

RESULTS

Ninety-three women completed the study (35 WLFO, 32 WLPO and 26 control), with significant weight-loss in WLFO (10.8+/-1.0%) and WLPO (12.4+/-1.0%) compared to the control group (P<0.0001). The WLFO, but not WLPO or control group, showed significant increases in adipose tissue LC n-3 PUFA (0.34+/-0.20 vs 0.17+/-0.10 and 0.16+/-0.10 %DHA, P<0.0001). Weight-loss showed significant improvements in insulin sensitivity (P<0.001), lipid profile (triglycerides P<0.05) and inflammation (sialic acid P<0.05). Time*group effects showed significant decreases in triglycerides (P<0.05) and increases in adiponectin (P<0.01) with LC n-3 PUFA, in the WLFO vs WLPO groups.

CONCLUSIONS

Weight-loss improved risk factors associated with CVD, with some additional benefits of LC n-3 PUFA on triglycerides and adiponectin. Given the current low dietary intake of LC n-3 PUFA, greater attention should be given to increase these fatty acids in the treatment of obesity.

Body fat reference curves for children

OBJECTIVE

To refine the diagnosis of childhood obesity by creating new sex-specific centile curves for body fat and to base these references on a simple and affordable method that could be widely adopted in clinical practice and surveys.

DESIGN

Body fat was measured by bio-impedance in 1985 Caucasian children aged 5-18 years from schools in Southern England. Smoothed centile charts were derived using the LMS method.

RESULTS

The new body fat curves reflect the known differences in the development of adiposity between boys and girls. The curves are similar by sex until puberty but then diverge markedly, with males proportionately decreasing body fat and females continuing to gain. These sex differences are not revealed by existing curves based on body mass index. We present charts in which cutoffs to define regions of 'underfat', 'normal', 'overfat' and 'obese' are set at the 2nd, 85th and 95th centiles. These have been designed to yield similar proportions of overweight/overfat and obese children to the IOTF body mass index cutoffs.

CONCLUSIONS

Direct assessment of adiposity, the component of overweight that leads to pathology, represents a significant advance over body mass index. Our new charts will be published by the Child Growth Foundation for clinical monitoring of body fat, along with the software to convert individual measurements to Z-scores.

Variability of appetite control mechanisms in response to 9 weeks of progressive overfeeding in humans

BACKGROUND

The current epidemic of obesity demonstrates that mechanisms for maintaining human energy balance are readily subverted by adverse environmental conditions. The critical elements of this dysregulation are poorly understood. Most previous research into what regulates the intake side of the energy balance equation has been handicapped by the use of short-term within-day experimental tests.

OBJECTIVE

We enrolled six non-obese men to a 17-week protocol involving three 21 days periods of progressive overfeeding (+20, +40 and +60%) separated by free diet periods to test for compensatory satiety.

RESULTS

Responses to overfeeding differed markedly with evidence of 'compensators' and 'non-compensators', but on average, subsequent food intake was stimulated rather than suppressed after overfeeding in spite of markedly elevated body fat (+13%) and fasting leptin (+116%).

DISCUSSION

The inefficient response of in-built appetite control mechanisms emphasizes the need to adopt intentional cognitive restraint in the modern environment when food is plentiful.

Secular trends in under-reporting in young people

National survey data show that reported energy intake has decreased in recent decades despite a rise in the prevalence of obesity. This disparity may be due to a secular increase in under-reporting or a quantitatively greater decrease in energy expenditure. This study examines the extent of under-reporting of energy intake in the National Diet and Nutrition Survey (NDNS) in young people aged 4-18 years in 1997 using published equations to calculate estimated energy requirements. It explores secular changes by comparison with the Diets of British School Children (DBSC) survey in 10-11- and 14-15-year-olds in 1983. In the NDNS, under-reporting (estimated energy requirements--energy intake) represented 21 % of energy needs in girls and 20 % in boys. The magnitude of under-reporting increased significantly with age (P<0.001) and was higher in overweight than lean individuals over 7 years of age. To compare reported energy intake in DBSC and NDNS, the estimated physical activity level from dietary records (dPAL=reported energy intake/predicted BMR) was calculated. If there were no under-reporting, dPAL would represent the subject's true activity level. However, dPAL from the NDNS was significantly lower than that from the DBSC by 8 % and 9 % in boys and girls for those aged 10-11 years, and by 14 % and 11 % for 14-15-year-olds respectively, reaching physiologically implausible levels in the 14-15-year-old girls (dPAL=1.17). If activity levels have remained constant between the two surveys, under-reporting has increased by 8-14 %. The evidence supports a secular trend towards increased under-reporting between the two surveys, but the precise magnitude cannot be quantified in the absence of historical measures of energy expenditure.