Paul J. Gately

The ABC of Physical Activity for Health: A consensus statement from the British Association of Sport and Exercise Sciences

Absract Our understanding of the relationship between physical activity and health is constantly evolving. Therefore, the British Association of Sport and Exercise Sciences convened a panel of experts to review the literature and produce guidelines that health professionals might use. In the ABC of Physical Activity for Health, A is for All healthy adults, B is for Beginners, and C is for Conditioned individuals. All healthy adults aged 18–65 years should aim to take part in at least 150 min of moderate-intensity aerobic activity each week, or at least 75 min of vigorous-intensity aerobic activity per week, or equivalent combinations of moderate- and vigorous-intensity activities. Moderate-intensity activities are those in which heart rate and breathing are raised, but it is possible to speak comfortably. Vigorous-intensity activities are those in which heart rate is higher, breathing is heavier, and conversation is harder. Aerobic activities should be undertaken in bouts of at least 10 min and, ideally, should be performed on five or more days a week. All healthy adults should also perform muscle-strengthening activities on two or more days a week. Weight training, circuit classes, yoga, and other muscle-strengthening activities offer additional health benefits and may help older adults to maintain physical independence. Beginners should work steadily towards meeting the physical activity levels recommended for all healthy adults. Even small increases in activity will bring some health benefits in the early stages and it is important to set achievable goals that provide success, build confidence, and increase motivation. For example, a beginner might be asked to walk an extra 10 min every other day for several weeks to slowly reach the recommended levels of activity for all healthy adults. It is also critical that beginners find activities they enjoy and gain support in becoming more active from family and friends. Conditioned individuals who have met the physical activity levels recommended for all healthy adults for at least 6 months may obtain additional health benefits by engaging in 300 min or more of moderate-intensity aerobic activity per week, or 150 min or more of vigorous-intensity aerobic activity each week, or equivalent combinations of moderate- and vigorous-intensity aerobic activities. Adults who find it difficult to maintain a normal weight and adults with increased risk of cardiovascular disease or type 2 diabetes may in particular benefit from going beyond the levels of activity recommended for all healthy adults and gradually progressing towards meeting the recommendations for conditioned individuals. Physical activity is beneficial to health with or without weight loss, but adults who find it difficult to maintain a normal weight should probably be encouraged to reduce energy intake and minimize time spent in sedentary behaviours to prevent further weight gain. Children and young people aged 5–16 years should accumulate at least 60 min of moderate-to-vigorous-intensity aerobic activity per day, including vigorous-intensity aerobic activities that improve bone density and muscle strength.

Children's residential weight-loss programs can work: a prospective cohort study of short-term outcomes for overweight and obese children.

Objective. The evidence base for child obesity treatment is weak. Childrens weight-loss camps, despite their popularity, have not been properly evaluated. This study evaluated the effectiveness of a residential weight-loss camp program for overweight and obese children. Methods. A total of 185 overweight children (mean age: 13.9 years) enrolled in 1 of 4 consecutive programs between 1999 and 2002 (intervention group) were compared with 94 children of similar ages who were not camp attendees, ie, 38 overweight children and 56 normal-weight children. The intervention group attended a 6-week (maximum) summer residential weight-loss camp. The program included a daily schedule of six 1-hour, skill-based, fun, physical activity sessions, moderate dietary restriction, and group-based educational sessions. All children were assessed for body weight, height, and other anthropometric measures, blood pressure, aerobic fitness, self-esteem, and selected sports skills. Results. Campers, who stayed for a mean of 29 days, lost 6.0 kg, reduced their BMI by 2.4 units, and reduced their BMI SD scores by 0.28. Fat mass decreased significantly (from 42.7 to 37.1 kg), whereas fat-free mass did not change. In contrast, both comparison groups gained weight during this period. Camp attendees also showed significant improvements in blood pressure, aerobic fitness, and self-esteem. Longer durations of stay were associated with greater improvements in outcomes. Conclusions. In the short term at least, this weight-loss program was effective across a range of health outcomes. Ongoing research is examining the maintenance of these improvements. Future research should investigate whether benefits can be generalized across weight-loss camps and how the intervention can be adapted to nonresidential, term-time settings.

The effects of a children's summer camp programme on weight loss, with a 10 month follow-up.

OBJECTIVE: To assess the long-term effects of a multidisciplinary approach involving structured fun-type skill learning physical activities in the treatment of obese and overweight children.DESIGN: A longitudinal investigation incorporating repeated measurements before and after the 8 week intervention and after the 44 week follow-up period.METHODS: The camp programme (Massachusetts, USA) utilised structured fun-based skill learning physical activities, moderate dietary restriction and behaviour modification. The primary aims of the intervention were to reduce body mass and promote the maintenance of the reduction in body mass using an alternative to standard exercise prescription.SUBJECTS: One-hundred and ninety-four children (64 boys and 130 girls, aged 12.6±2.5 y) enrolled at a summer weight loss camp, of which 102 children (38 boys and 64 girls aged 13.6±2.4 y) returned 1 y later.MEASUREMENTS: On commencement of the programme all children were assessed for body mass and stature. At follow-up, data was available on 102 subjects for body mass and stature.RESULTS: Over the 8 week intervention significant reductions (P=0.00) in body mass were obtained. During the 44 week follow-up significant increases (P=0.00) were noted in body mass, body mass index (BMI) and stature, but as expected there were large variations in the responses. One year after the initial measures had been taken mean body mass and BMI were lower than at the start of the intervention, BMI significantly so (week 0, 32.9±7.4 kg/m2; week 8 29.1±6.5 kg/m2; week 52, 30.05±7.04 kg/m2); (P=0.00). Stature increased significantly (week 0, 1.58±0.12 m; week 52, 1.64±0.11 m) (P=0.00) during this period, demonstrating a reduction in mean body mass over a 1 y period whilst subjects continued to increase in stature. When changes in BMI are analysed with the use of standard scores, there is a non-significant increase (P=0.07) in BMI during the follow-up phase and 89% of children had a lower BMI than at week 0.CONCLUSIONS: These findings suggest that the use of a structured fun-based skill learning programme may provide an alternative method of exercise prescription to help children prolong the effects of the 8 week intervention. Further investigations will help identify the key factors that are necessary for long-term lifestyle modification.

Children's weight-loss camps: psychological benefit or jeopardy?

OBJECTIVES: To investigate the change in body image, self-esteem, and worries in obese adolescents attending a residential, weight-loss camp.DESIGN: A longitudinal intervention study, with a nonintervention comparison group of lean adolescents.PARTICIPANTS: A total of 57 obese adolescents (age: 13,11; BMI: 32.6 kg/m2) and 38 normal weight comparison adolescents.MEASURES:Self-esteem, salience of weight-related issues, body shape preference, weight and height at the start, and end of the weight-loss camp (mean stay: 4 weeks).RESULTS: The obese adolescents lost 5.6 kg, reduced their BMI by 2.1 kg/m2, and BMI s.d. score by 0.28 while comparison children gained weight. Body shape dissatisfaction significantly decreased and self-esteem increased on measures of global self-worth, athletic competence, and physical appearance, in the camp attendees. This improvement took place without any exacerbation of existing worries about appearance or weight.CONCLUSIONS: While obese adolescents had lower self-worth and greater body dissatisfaction relative to the comparison children at the start of the camp, the intervention improved their psychological state. Greater weight loss was associated with greater psychological improvement, indicating the value of the intervention and the relevance of psychological change in effective treatment.

Neuropsychological assessment as a predictor of weight loss in obese adolescents.

Background:Obese individuals are known to be more impulsive than their normal-weight counterparts. Impulsivity has been postulated to be a predictor of weight loss.Design:A pre–post study was designed to determine for the first time whether impulsivity changed with weight loss during a lifestyle and physical activity intervention programme lasting 2–8 weeks.Subjects:Fifty-three obese adolescents with a body mass index (BMI) of 33.75±7.9 attending a residential camp were tested and compared at baseline with 50 non-obese adolescents with a mean BMI of 20.6±2.3.Measurements:Inhibitory control was measured with the CANTAB (Cambridge Cognition, Cambridge, UK) Stop Signal Task. MATLAB (The Mathswork Inc., Natick, MA, USA) was used to measure the temporal discounting constant.Results:The obese group was more impulsive than the normal weight adolescents. BMI reduced significantly from 33.76 kg m−2 to 30.93 kg m−2 after completing camp. The stop signal reaction time (SSRT) decreased from 225.38±94.22 to 173.76±107.05 ms (n=47, P=0.0001). A reduction in inhibitory control during camp was predictive of those who showed the greatest reduction in BMI (Wilks’ Lambda=0.9, F(1,50)=4.85, P=0.034). The number of weeks in camp (Wilks’ Lambda=0.83, F(1,50)=9.826, P=0.003) and the age of the adolescents (Wilks’ Lambda=0.87, F(1,50)=5.98, P=0.02) were significantly associated with a reduction in inhibitory control as measured by the SSRT. A longer stay in camp was associated with a greater reduction in SSRT (B=25.45, t=2.02, P=0.05). Increasing age had a significant moderating role in the reduction of inhibitory control (B=−0.3, t=−0.034, P=0.05). Temporal discounting for monetary reward also fell significantly during camp.Conclusion:This study highlights the potential to identify those who are obese by using an easy-to-measure psychometric test. Furthermore, it is the first study to report a reduction in impulsivity and an improvement in well-being as part of a government-approved residential camp for obese adolescents. The potential mechanisms for change in impulsivity with weight are discussed.

Does a high-protein diet improve weight loss in overweight and obese children?

Objective: To evaluate the effect of a high‐protein diet on anthropometry, body composition, subjective appetite, and mood sensations in overweight and obese children attending a residential weight‐loss camp.

Can we recognise obesity clinically

The aim of this study was to ascertain whether health care professionals are able to accurately identify overweight and obese children by observation alone. Eighty health care professionals were asked to view photographs of 33 children and assign each into one of six categories, ranging from “very underweight” to “obese”. The health care professionals’ categorisation was compared with the children’s degree of adiposity based on conventional clinical criteria for BMI. The health care professionals were found to be generally poor at assessing the weight status of the children, and in particular tended to underestimate overweight and obesity in children. This study suggests that it is not appropriate to rely on informal assessment to identify obesity and highlights the need for health care professionals to be aware of their lack of accuracy in this regard.

Obese young people's accounts of intervention impact

OBJECTIVE To uncover in-depth qualitative accounts of intervention impact from obese young people during a period of lifestyle change after attending a residential weight-loss camp. METHODS An innovative, progressively focused process of (1) single end-of-stay interviews, (2) interviews repeated in the home environment at 3 months and (3) 9 months. Comprehensive data were collected from five information-rich cases who contributed at each stage. Verbatim transcripts were analysed to identify issues associated with camp impact. RESULTS Reporting positive in-camp experiences, there were also anxieties about returning home and successfully translating knowledge and behaviors into longer term strategies. Inductive analysis suggested cognitive ambiguity in relation to positive camp impact. This developed and intensified over the 9 months of post-camp experience, despite the help of supportive others. CONCLUSION Young people described a positive post-camp impact that continued into the home environment. Unexpectedly, though it was also an ambiguous experience. Cognitive ambiguity created behavioral conflict which undermined motivation for sustained healthy living. PRACTICE IMPLICATIONS These unique accounts enable service providers to better understand post-camp experiences and use them to work with young people towards more positive outcomes. Even after intensive and successful intervention young people may still require ongoing support for continued lifestyle change.

Cross‐Sectional Comparisons of BMI and Waist Circumference in British Children: Mixed Public Health Messages

Research suggests that there has been a leveling off in obesity prevalence occurring in the child population. However, a concern with the evidence base is that all of the studies have relied upon the use of BMI. The purpose of this study was to compare waist circumference (WC), BMI, and waist‐to‐height ratio (WHtR) data in three different sample of children (total number: 14,697) typically aged 11–12 years. Obesity prevalence defined by BMI did not change significantly between measurement years (2005 boys 20.6%, girls 18.0%; 2006 boys 19.3%, girls 17.3%; 2007 boys 19.8%, girls 16.4%). Obesity prevalence defined by WC was considerably higher especially, in girls (2005 boys 26.3%, girls 35.6%; 2006 boys 20.3%, girls 28.2%; 2007 boys 22.1%, girls 30.1%). The prevalence of children defined as “at risk” according to WHtR (2005 boys 23.3%, girls 21.1%; 2006 boys 16.7%, girls 15.6%; 2007 boys 17.6%, girls 17.2%) was found to be between obesity prevalence, estimated using BMI and WC. This data are the most up to date collection that includes BMI and WC in three large samples of children and clearly demonstrates inconsistencies between different measurements based on current classification systems. There is a need to understand the relationship between BMI and WC, with growth and health risk to establish a consistent public health message that is easily understood by the public.

RCT of a High‐protein Diet on Hunger Motivation and Weight‐loss in Obese Children: An Extension and Replication

This study aimed to evaluate the weight loss and hunger motivation effects of an energy‐restricted high‐protein (HP) diet in overweight and obese children. In total, 95 overweight and obese children attended an 8‐week (maximum) program of physical activity, reduced‐energy intake, and behavior change education. Children were randomly assigned to one of two isoenergetic diets (standard (SP): 15% protein; HP: 25% protein), based on individually estimated energy requirements. Anthropometry and body composition were assessed at the start and end of the program and appetite and mood ratings completed on the first 3 consecutive weekdays of each week children attended camp. The HP diet had no greater effect on weight loss, body composition, or changes in appetite or mood when compared to the SP diet. Overall, campers lost 5.2 ± 3.0 kg in body weight and reduced their BMI standard deviation score (sds) by 0.25. Ratings of desire to eat increased significantly over the duration of the intervention, irrespective of diet. This is the third time we have reported an increase in hunger motivation in weight‐loss campers and replicates our previous failure to block this with a higher protein diet. Further work is warranted into the management of hunger motivation as a result of negative energy balance.