From instinct to intellect: the challenge of maintaining healthy weight in the modern world

Walking around the preferred speed: examination of metabolic, perceptual, spatiotemporal and stability parameters

Walking is the most accessible and common type of physical activity. Exercising at one's self-selected intensity could provide long-term benefits as compared to following prescribed intensities. The aim of this study was to simultaneously examine metabolic, perceptual, spatiotemporal and stability parameters at an absolute 3 km·h-1 speed range around the individual preferred walking speed (PWS). Thirty-four young sedentary adults (18 women) volunteered to walk at seven speeds relative to their PWS in 3-min trials interspaced with 3-min rest intervals. Results indicated a significant main effect of speed on all studied variables. While metabolic, perceptual and spatiotemporal values were sensitive to the smallest change in speed (i.e., 0.5 km·h-1), a significant increase in the rate of carbohydrate oxidation and decrease in %fat oxidation were only observed at speeds above PWS. Results also revealed significantly higher coefficients of variation for stride characteristics at speeds below PWS only. Moreover, analyses of best fit models showed a quadratic relationship between most variables and speed, with the exceptions of metabolic cost of transport, rating of perceived exertion and stride duration that changed exponentially with speed. PWS coincided with optimized mechanical efficiency, fuel oxidation and gait stability. This indicated that walking below PWS decreased both mechanical efficiency and stability of gait, while walking above PWS increased carbohydrate oxidation. Those factors seem to play an important role as determinants of PWS. We suggest that walking at PWS may provide benefits in terms of fat oxidation while optimizing gait stability.

Resemblance in Physical Activity in Families with Children in Time Segments during the Week: The Lolland-Falster Health Study

PURPOSE

Evidence of shared physical activity (PA) habits within families is inconsistent. The present study aimed at examining intrafamily resemblance in PA during different time segments of the week.

METHOD

This cross-sectional study used data from the Danish household-based population study Lolland-Falster Health Study. We assessed time spent in various PA intensities and behaviors using a dual-accelerometer system (Axivity AX3). At least one parent and one child per household provided data for a minimum of three weekdays and one weekend day. We analyzed three time segments: early weekdays, late weekdays, and weekends. A linear mixed model regression analysis was used to estimate intraclass correlation coefficients (ICC) of the total family, parent-child dyads, siblings, and parent-parent dyads for PA outcomes, adjusting for sex, age, parental education, and the interaction between sex and age.

RESULTS

We included 774 parents (57.9% female, 42.8 ± 7 yr) and 802 children (54.2% girls, 11.1 ± 4.3 yr) nested within 523 families. The clustering among the total family was stronger during late weekdays (ICC = 0.11-0.31) and weekends (ICC = 0.14-0.29) than during early weekdays (ICC = 0.02-0.19). We found stronger clustering among siblings (ICC = 0.08-0.47) and between parents (ICC = 0.02-0.52) than between parents and children (ICC < 0.01-0.37). Generally, the clustering was strongest for light PA, and among PA behaviors, walking showed the highest resemblance across all subgroups.

CONCLUSION

Initiatives to promote children's PA that involve parent or sibling coparticipation may focus on the time segment and activity types with the highest resemblance. For the family as a whole, promoting walking or limiting sedentary activities may be a potential target for interventions during late weekdays and weekends.Trial registration: Clinicaltrials.gov (NCT02482896).

Gastronomy unravelled by physics: Gastrophysics

Useful attempts to shed light on the nature of gastronomy from a scientific point of view and to unravel the crucial connection between food, eating and well-being are currently underrepresented in the scientific literature. However, several scientific disciplines ranging from the natural to the social sciences offer valuable new perspectives on gastronomy. As one of the key disciplines in natural science, physics offers original and rigorous perspectives on all processes and structures constrained by the laws of nature. The emerging discipline called gastrophysics employs the full range of concepts, techniques and methods from physics to generate useful scientific input to the complex and holistic reflections on gastronomy. Relying on a review of the existing literature, this article illustrates how a science-based gastrophysics emerges, to a large extent from the convoluted history of food science as well as from various recent ‐ and often overlapping ‐ attempts to combine modern scientific methodology to questions from gastronomy. However, the present review also insists on a physics-inspired methodology to handle scale and complexity in food preparation and consumption across length scales from sub-molecular to entire foods. We exemplify how gastrophysics directly helps to develop gastronomy and how it adds to current approaches in traditional food science. We also suggest that gastrophysics may prove relevant in the context of the ongoing food transformation, which focuses strongly on sustainability, but where the importance of gastronomic aspects in this transformation is greatly needed.

Preference for Intuition and Deliberation in Eating Decision-making: Scale validation and associations with eating behaviour and health

OBJECTIVES

Two distinct lines of research separately regard either deliberately regulated eating or intuitive eating as most beneficial for health. The present research aims to integrate these seemingly contradictory findings by investigating the relationships between Preference for Intuition and Deliberation in Eating Decision-making (E-PID) and subjective and objective health-related parameters using a newly developed scale.

DESIGN

Study 1: online survey; Study 2: cross-sectional community cohort sample.

METHODS

Study 1 (N = 699) assessed E-PID, intuitive, restrained, and external eating, motivation to eat healthily, domain-unspecific Preference for Intuition and Deliberation, and general self-control. Study 2 (N = 1,212) assessed E-PID, positive eating, intention to eat healthily, eating behaviour, and objective health risk factors (BMI, waist circumference, blood pressure, fasting serum glucose, HDL cholesterol, triglycerides).

RESULTS

Study 1 confirmed a two-factor structure and provided evidence for construct validity: A higher preference for intuition was positively related to intuitive eating, while a higher preference for deliberation was associated with increased dietary restraint. In Study 2, preference for deliberation was positively related to the intention to eat healthy, healthy eating behaviour, and health parameters. Preference for intuition was generally unrelated to health parameters, although a higher preference for intuition was related to a somewhat unhealthier eating pattern.

CONCLUSIONS

Preference for intuition and deliberation when making food choices are two distinct decision-making styles: The former focuses on internal cues, while the latter focuses on cognitive regulation of food intake. Despite these differences, neither decision-making style was shown to be detrimental.

Causes of Variation in Food Preference in the Netherlands

Our current society is characterized by an increased availability of industrially processed foods with high salt, fat and sugar content. How is it that some people prefer these unhealthy foods while others prefer more healthy foods? It is suggested that both genetic and environmental factors play a role. The aim of this study was to (1) identify food preference clusters in the largest twin-family study into food preference to date and (2) determine the relative contribution of genetic and environmental factors to individual differences in food preference in the Netherlands. Principal component analysis was performed to identify the preference clusters by using data on food liking/disliking from 16,541 adult multiples and their family members. To estimate the heritability of food preference, the data of 7833 twins were used in structural equation models. We identified seven food preference clusters (Meat, Fish, Fruits, Vegetables, Savory snacks, Sweet snacks and Spices) and one cluster with Drinks. Broad-sense heritability (additive [A] + dominant [D] genetic factors) for these clusters varied between .36 and .60. Dominant genetic effects were found for the clusters Fruit, Fish (males only) and Spices. Quantitative sex differences were found for Meat, Fish and Savory snacks and Drinks. To conclude, our study convincingly showed that genetic factors play a significant role in food preference. A next important step is to identify these genes because genetic vulnerability for food preference is expected to be linked to actual food consumption and different diet-related disorders.

Bile acid receptor TGR5 is critically involved in preference for dietary lipids and obesity

We investigated the implication of Takeda G protein-coupled receptor 5 (TGR5) in fat preference and fat sensing in taste bud cells (TBC) in C57BL/6 wild-type (WT) and TGR5 knock out (TGR5^-/^-) male mice maintained for 20 weeks on a high-fat diet (HFD). We also assessed the implication of TGR5 single nucleotide polymorphism (SNP) in young obese humans. The high-fat diet (HFD)-fed TGR5^-/^- mice were more obese, marked with higher liver weight, lipidemia and steatosis than WT obese mice. The TGR5^-/^- obese mice exhibited high daily food/energy intake, fat mass and inflammatory status. WT obese mice lost the preference for dietary fat, but the TGR5^-/^- obese mice exhibited no loss towards the attraction for lipids. In lingual TBC, the fatty acid-triggered Ca²⁺ signaling was decreased in WT obese mice; however, it was increased in TBC from TGR5^-/^- obese mice. Fatty acid-induced in vitro release of GLP-1 was higher, but PYY concentrations were lower, in TBC from TGR5^-/^- obese mice than those in WT obese mice. We noticed an association between obesity and variations in TGR5 rs11554825 SNP. Finally, we can state that TGR5 modulates fat eating behavior and obesity.

The Effects of Obesity in Asthma

PURPOSE OF REVIEW

Rising costs and increasing morbidity makes the identification and treatment of high-risk asthma phenotypes important. In this review, we outline the complex relationship between obesity and asthma.

RECENT FINDINGS

Studies have confirmed a bi-directional relationship between obesity and asthma. Pathophysiological factors implicated include genetic risk, the effect of diet and microbiome, and obesity-related cytokines. There have been robust, albeit derived, efforts to phenotype this group with distinct clinical presentations based on age of onset of asthma. Unfortunately, the poor performance of biomarkers and traditional lung function testing has impeded diagnosis, phenotyping, and management of the obese asthma patient. There is also a lack of targeted interventions with weight loss showing some benefits. Obesity increases the prevalence of asthma and is associated with worse outcomes. There are unique research and clinical challenges while managing this group of patients.

'It's Important to Make Changes.' Insights about Motivators and Enablers of Healthy Lifestyle Modification from Young Aboriginal Men in Western Australia

Lifestyle modification can improve the health of people with or at risk of non-communicable diseases; however, initiating and maintaining positive health behaviours including healthy eating and physical activity is challenging. Young remote Aboriginal people who had successfully made significant healthy lifestyle changes were sought out to explore how they achieved this success. Four Aboriginal men aged 20⁻35 years were identified and consented to participate. Their perceptions of motivation for change, strategies, and facilitators and barriers were explored through in-depth interviews. Themes developed from the interviews included self-efficacy, self-reliance, and increased knowledge and altered health beliefs underpinning change. Participants with diabetes were highly motivated to avoid diabetes complications and had a strong belief that their actions could achieve this. In a setting with high levels of disadvantage, participants had relatively favourable socioeconomic circumstances with solid social supports. These findings highlight that lifestyle modification programs that foster internal motivation, enhance key health knowledge, and modify health beliefs and risk perception are needed. Increasing diabetes awareness among at-risk young people is important, emphasising the largely preventable and potentially reversible nature of the condition. Broad health improvements and individual changes will be facilitated by equitable socioeconomic circumstances and environments that support health.

Supporting a sugar tax in New Zealand: Sugar sweetened beverage ('fizzy drink') consumption as a normal behaviour within the obesogenic environment

Background

Excessive intake of sugar sweetened beverages (SSBs) is a preventable cause of death. While some countries have implemented a tax on SSBs, other countries, such as New Zealand, rely on industry self-regulation and individual responsibility, such as referring to labels, to control one's own sugar intake from SSBs. The present study examines whether SSB consumers consciously control their diet and therefore interventions such as better labelling might be effective, or alternatively, whether SSB consumers engage in a general pattern of unhealthy eating, and in which case government regulation would be advisable.

Aim

To explore self-reported dietary consumption and conscious healthy eating behaviours of New Zealand consumers who had consumed SSBs over a 24 hour period.

Method

A cross-sectional survey of a representative sample of 2007 New Zealanders, measuring their food and beverage intake over a 24 hour period and self-reported intentions to eat healthily. Within this was a measurement of SSB consumption in the 24 hour period.

Results

Multivariable logistic regression revealed that compared to non-SSB consumers, SSB consumers were more likely to have eaten the following: confectionery; fast food; pre-prepared food; biscuits, cakes or pastries; takeaways; ice-cream/dessert. SSB consumption was also associated with a lower likelihood of referring to food labels, less conscious effort to eat healthily, and to less likely to avoid: sugar; fat; calories; food additives; pre-prepared food. SSB consumers were also less likely to have eaten breakfast, or made a meal at home made from scratch.

Conclusion

SSB consumers were more likely than non-SSB consumers to demonstrate a general pattern of unhealthy eating and were less likely to report consciously controlling their diet. The findings raise significant concerns regarding the efficacy of individual and industry self-regulation and lend support to stronger government targeted interventions.

Gender Differences in Food Choice: Effects of Superior Temporal Sulcus Stimulation

The easy availability of food has caused a shift from eating for survival to hedonic eating. Women, compared to men, have shown to respond differently to food cues in the environment on a behavioral and a neural level, in particular to energy rich (compared to low energy) foods. It has been demonstrated that the right posterior superior temporal sulcus (STS) is the only region exhibiting greater activation for high vs. low calorie food choices. In order to test for a possible causal role of STS in food choice, we applied high frequency transcranial random noise stimulation (tRNS) on STS assuming a different response pattern between males and females. Our participants (18 females, 17 males) performed a forced choice task between food pairs matched for individual liking but differed in calorie, during the left STS, right STS stimulation and sham condition. Male participants showed a general preference for low calorie (LC) foods compared to females. In addition, we observed in males, but not in females, an increase of high calorie (HC) food choice during right STS tRNS compared to sham condition and left STS tRNS. Finally, we found an increase of missed choices during right STS stimulation compared to sham condition and left STS stimulation. In conclusion, thanks to tRNS evidence, we both confirm the involvement and suggest a causal role of right posterior STS in feeding behavior. Moreover, we suggest that gender differences exist in STS mechanisms underlying food choice.

N-of-1 study of weight loss maintenance assessing predictors of physical activity, adherence to weight loss plan and weight change

OBJECTIVE

Behaviour change interventions are effective in supporting individuals to achieve clinically significant weight loss, but weight loss maintenance (WLM) is less often attained. This study examined predictive variables associated with WLM.

DESIGN

N-of-1 study with daily ecological momentary assessment combined with objective measurement of weight and physical activity, collected with wireless devices (Fitbit™) for six months. Eight previously obese adults who had lost over 5% of their body weight in the past year took part. Data were analysed using time series methods.

MAIN OUTCOMES MEASURES

Predictor variables were based on five theoretical themes: maintenance motives, self-regulation, personal resources, habits, and environmental influences. Dependent variables were: objectively estimated step count and weight, and self-reported WLM plan adherence.

RESULTS

For all participants, daily fluctuations in self-reported adherence to their WLM plan were significantly associated with most of the explanatory variables, including maintenance motivation and satisfaction with outcomes, self-regulation, habit, and stable environment. Personal resources were not a consistent predictor of plan adherence.

CONCLUSION

This is the first study to assess theoretical predictions of WLM within individuals. WLM is a dynamic process including the interplay of motivation, self-regulation, habit, resources, and perceptions of environmental context. Individuals maintaining their weight have unique psychological profiles which could be accounted for in interventions.

Cardiovascular Risk Factors of Adults Age 20-49 Years in the United States, 1971-2012: A Series of Cross-Sectional Studies

Background

The health of younger adults in the U.S. has important public health and economic-related implications. However, previous literature is insufficient to fully understand how the health of this group has changed over time. This study examined generational differences in cardiovascular risk factors of younger adults over the past 40 years.

Methods

Data were from 6 nationally representative cross-sectional National Health and Nutrition Examination Surveys (1971–2012; N = 44,670). Participants were adults age 20–49 years who self-reported sociodemographic characteristics and health conditions, and had examination/laboratory measures for hypertension, hyperlipidemia, diabetes, obesity, and chronic kidney disease. Prevalences of sociodemographic characteristics and health status were determined by study period. Logistic regression was used to determine the odds [odds ratio (OR), 95% confidence interval] of health conditions by study period: models adjusted only for age, sex, and race, and fully adjusted models additionally adjusted for socioeconomic characteristics, smoking, BMI, diabetes, and/or hypertension (depending on the outcome) were assessed.

Results

Participants in 2009–2012 were significantly more likely to be obese and have diabetes compared to those in 1971–1975 (OR = 4.98, 3.57–6.97; OR = 3.49, 1.59–7.65, respectively, fully adjusted). Participants in 2009–2012 vs. 1988–1994 were significantly more likely to have had hypertension but uncontrolled hypertension was significantly less likely (OR = 0.67, 0.52–0.86, fully adjusted). There was no difference over time for high cholesterol, but uncontrolled high cholesterol was significantly less likely in 2009–2012 vs. 1988–1994 (OR = 0.80, 0.68–0.94, fully adjusted). The use of hypertensive and cholesterol medications increased while chronic kidney and cardiovascular diseases were relatively stable.

Conclusions

Cardiovascular risk factors of younger U.S. adults have worsened over the past 40 years, but treatment for hypertension and high cholesterol has improved. The sub-optimal and worsening health in younger adults may have a substantial impact on health care utilization and costs, and should be considered when developing health care practices.

Association between obesity and asthma - epidemiology, pathophysiology and clinical profile

Obesity is a risk factor for asthma, and obese asthmatics have lower disease control and increased symptom severity. Several putative links have been proposed, including genetics, mechanical restriction of the chest and the intake of corticosteroids. The most consistent evidence, however, comes from studies of cytokines produced by the adipose tissue called adipokines. Adipokine imbalance is associated with both proinflammatory status and asthma. Although reverse causation has been proposed, it is now acknowledged that obesity precedes asthma symptoms. Nevertheless, prenatal origins of both conditions complicate the search for causality. There is a confirmed role of neuro-immune cross-talk mediating obesity-induced asthma, with leptin playing a key role in these processes. Obesity-induced asthma is now considered a distinct asthma phenotype. In fact, it is one of the most important determinants of asthma phenotypes. Two main subphenotypes have been distinguished. The first phenotype, which affects adult women, is characterised by later onset and is more likely to be non-atopic. The childhood obesity-induced asthma phenotype is characterised by primary and predominantly atopic asthma. In obesity-induced asthma, the immune responses are shifted towards T helper (Th) 1 polarisation rather than the typical atopic Th2 immunological profile. Moreover, obese asthmatics might respond differently to environmental triggers. The high cost of treatment of obesity-related asthma, and the burden it causes for the patients and their families call for urgent intervention. Phenotype-specific approaches seem to be crucial for the success of prevention and treatment.

Is there such a thing as sustainable physical activity?

There is a global need to diminish climate gas emissions, and a simultaneous call for enhanced levels of physical activity. Increased physical activity entails reduced risk for overweight and chronic diseases, as well as a potential to reduce transport's major contribution to global CO₂ emissions. However, increased physical activity level also implies increased energy expenditure. Therefore, we aim to introduce the concept of sustainable physical activity, and to suggest certain physical activity habits due to their potentially sustainable properties. Worldwide, a third of adults and four fifths of adolescents ought to be more physically active in order to comply with current physical activity recommendations. Yet, considering upcoming resource challenges, types of physical activity should be taken into account. Active transportation represents carbon-friendly means of transportation as well as an opportunity for enhanced physical activity. Physical activity conducted in the local community is likely to favor sustainability through less use of fossil fuel, as it makes transportation redundant. Moreover, going "back to basic", using less equipment and appliances for everyday tasks could contribute toward energy balance through increased physical activity, and could decrease resource use. Finally, balancing food intake and energy expenditure would require less food production with accompanying energy savings.

Development and psychometric properties of a self-regulation scale about leisure time physical activity in Iranian male adolescents

Background:

Self-regulation is one of the current psychological concepts that have been known as a determinant of leisure time physical activity. Due to cultural and social diversity in different societies and age groups, application of specific questionnaires is essential to perform investigations about physical activities. The aim of this study is development and evaluation of psychometric properties of a self-regulation questionnaire about leisure time physical activity in Iranian male adolescents.

Materials and Methods:

This cross-sectional study was conducted in 2013, and data of 603 male students from 12 high schools in Isfahan were collected. A comprehensive literature review and similar questionnaire review were conducted and 25 items were selected or developed to measure self-regulation. Comprehensibility of items was evaluated in a pilot study and an expert panel evaluated face and content validity. Exploratory factors analysis (EFA) was used for evaluation of construct validity and extraction of sub-constructs of self-regulation. Leisure time physical activity was assessed using International Physical Activity Questionnaire (IPAQ).

Results:

The mean age of the participants was 16.3 years (SD =1.0) and the range was 15-19 years. Cronbach's α coefficient of the questionnaire in the pilot and main study was 0.84 and 0.90, respectively. EFA resulted in four sub-constructs including “enlistment of social support”, “goal setting”, “self-construction”, and “self-monitoring”, which explained 63.6% of the variance of self-regulation.

Conclusions:

Results of this investigation provide some support to the validity and reliability of the 16-item questionnaire of self-regulation abut leisure time physical activity in the target group.

Trajectories of Body Mass Index from Young Adulthood to Middle Age among Canadian Men and Women

Knowledge regarding the heterogeneity of BMI trajectories is limited for the Canadian population. Using latent class growth modelling, four distinct BMI trajectories of individuals from young adulthood to middle age were identified for both women and men from the longitudinal data of the National Population Health Survey. The associations between BMI trajectories and the individuals’ sociodemographic characteristics and behavioural factors were also examined. Aboriginal women were found more likely to be in the long-term overweight or obese groups. It reveals that increased years of smoking, drinking, and being physically active were associated with lowering the BMI trajectory in all groups for both women and men, with some exceptions in the long-term normal weight group for men. Increased years of rural living, being employed, and living with low income were associated with raising the BMI trajectory in all groups for women and in some groups for men. Food insecurity was associated with raising the BMI trajectory in each group for both women and men.

Do overweight workers profit by workplace health promotion, more than their normal-weight peers? Evaluation of a worksite intervention

Background

Worksite health promotion programs have been identified as strongly effective in decreasing body weight and increasing awareness and change in health behavior. Aim of this study is to determine the effects of a multi-component intervention in workplace health promotion.

Methods

In a controlled study trail, 1,573 workers of a logistics company had the chance to participate in a one year worksite health promotion program. Main elements of the multi-component intervention were physical activity training in combination with nutrition counseling. Employees completed a questionnaire at baseline and then again after twelve month. Main outcome variables were changes in body weight and health behaviors. Secondary outcomes were subjective health indicators.

Results

Our results showed preliminary improvements in physical activity and eating behavior among normal weight and overweight/obesity weight groups. No significant weight reduction could be found, only a minimal reduction of BMI. The reduction was larger in the overweight group. Workers considered overweight or obese showed significantly greater body weight loss and changes in eating behavior than workers with a normal weight status. Workers with obesity/overweight scored their general health status significantly lower than their colleagues with normal weight status. No significant improvements were found for overall perception of health status between baseline and follow-up in the BMI-groups.

Conclusion

This 12-month intervention-control study suggests that a well-implemented multi-component workplace health promotion program may support substantial change in health behavior (e.g. nutrition and physical activity). It is indicated that overweight employees may especially profit from such worksite health promotion. An investigation of long-term effects of this multi-component intervention is strongly recommended.

High-intensity interval exercise training for public health: a big HIT or shall we HIT it on the head?

Background

The efficacy of high-intensity interval training for a broad spectrum of cardio-metabolic health outcomes is not in question. Rather, the effectiveness of this form of exercise is at stake. In this paper we debate the issues concerning the likely success or failure of high-intensity interval training interventions for population-level health promotion.

Discussion

Biddle maintains that high-intensity interval training cannot be a viable public health strategy as it will not be adopted or maintained by many people. This conclusion is based on an analysis of perceptions of competence, the psychologically aversive nature of high-intensity exercise, the affective component of attitudes, the less conscious elements of motivated behaviour that reflect our likes and dislikes, and analysis using the RE-AIM framework. Batterham argues that this appraisal is based on a constrained and outmoded definition of high-intensity interval training and that truly practical and scalable protocols have been - and continue to be - developed. He contends that the purported displeasure associated with this type of exercise has been overstated. Biddle suggests that the way forward is to help the least active become more active rather than the already active to do more. Batterham claims that traditional physical activity promotion has been a spectacular failure. He proposes that, within an evolutionary health promotion framework, high-intensity interval training could be a successful population strategy for producing rapid physiological adaptations benefiting public health, independent of changes in total physical activity energy expenditure.

Summary

Biddle recommends that we focus our attention elsewhere if we want population-level gains in physical activity impacting public health. His conclusion is based on his belief that high-intensity interval training interventions will have limited reach, effectiveness, and adoption, and poor implementation and maintenance. In contrast, Batterham maintains that there is genuine potential for scalable, enjoyable high-intensity interval exercise interventions to contribute substantially to addressing areas of public health priority, including prevention and treatment of Type 2 diabetes and cardiovascular disease.

Functional MRI of Challenging Food Choices: Forced Choice between Equally Liked High- and Low-Calorie Foods in the Absence of Hunger

We are continuously exposed to food and during the day we make many food choices. These choices play an important role in the regulation of food intake and thereby in weight management. Therefore, it is important to obtain more insight into the mechanisms that underlie these choices. While several food choice functional MRI (fMRI) studies have been conducted, the effect of energy content on neural responses during food choice has, to our knowledge, not been investigated before. Our objective was to examine brain responses during food choices between equally liked high- and low-calorie foods in the absence of hunger. During a 10-min fMRI scan 19 normal weight volunteers performed a forced-choice task. Food pairs were matched on individual liking but differed in perceived and actual caloric content (high-low). Food choice compared with non-food choice elicited stronger unilateral activation in the left insula, superior temporal sulcus, posterior cingulate gyrus and (pre)cuneus. This suggests that the food stimuli were more salient despite subject’s low motivation to eat. The right superior temporal sulcus (STS) was the only region that exhibited greater activation for high versus low calorie food choices between foods matched on liking. Together with previous studies, this suggests that STS activation during food evaluation and choice may reflect the food’s biological relevance independent of food preference. This novel finding warrants further research into the effects of hunger state and weight status on STS, which may provide a marker of biological relevance.

The Health at Every Size paradigm and obesity: missing empirical evidence may help push the reframing obesity debate forward

A Health at Every Size (HAES) approach has been proposed to address weight bias and stigma in individuals living with obesity, and more recently articulated as a promising public health approach beyond the prevailing focus on weight status as a health outcome. The purpose of this article is to examine our understanding of HAES within the context of public health approaches to obesity, and to present strengths and limitations of the available evidence. Advancing our understanding of HAES from a public health perspective requires us to move beyond an ideological debate and give greater attention to the need for empirical studies across a range of populations. Only then can the value of HAES, as a weight-neutral, public health approach for the prevention of obesity and other chronic diseases, be fully understood.

Physical activity and cancer survivorship

There has been an increase in the cancer survivor population in the United States over the past several decades primarily due to improvements in early detection of first malignancies and effective treatment modalities. A wealth of evidence has demonstrated that regular physical activity is associated with a lower risk of death, all-cause mortality, cancer recurrence, and several chronic diseases, including type 2 diabetes and cardiovascular disease, common comorbid conditions in people who have survived cancer. Physical activity also is a central component of weight management.

METHODS

This review summarizes the current physical activity recommendations and the evidence linking physical activity to improvements in weight management, physiological effects, and psychological health outcomes for cancer survivors.

RESULTS

The available literature suggests physical activity is safe and is positively associated with weight management, cardiorespiratory fitness, muscular strength and endurance, quality of life, fatigue, and other psychosocial factors in cancer survivors. Yet relationships related to specific cancer diagnoses, treatments, and underlying cardiometabolic mechanisms associated with survival have not been thoroughly examined in randomized controlled trials. Furthermore, factors that influence adherence to physical activity behaviors must be identified to develop effective exercise programs. The use of objective measures of physical activity and the standardization of reporting outcome measures within intervention trials are needed to complement this effort.

CONCLUSIONS

Healthcare providers should consider individual differences among cancer survivors and tailor physical activity programs to meet the individual needs of the patient to assist in the adoption and maintenance of a physically active lifestyle.

The association between different types of exercise and energy expenditure in young nonoverweight and overweight adults

With decades of trends for decreasing activity during work and travel, exercise becomes an important contributor to total physical activity (PA) and energy expenditure. The purpose of this study was to examine the contribution of different types of exercise to the variability in energy expenditure and time spent at different PA intensities in young adults. Four hundred and seventeen adults (49.9% male; 46.2 overweight/obese) between 21 and 36 years of age provided valid objective PA and energy expenditure data, assessed via the SenseWear Armband (BodyMedia Inc.). Frequency and duration of participation in various exercise types was self-reported. Weight status was based on body mass index (BMI) (kg/m(2)) with body weight and height being measured according to standard procedures. Eighty-four percent of the participants reported regular exercise engagement with no difference in participation rate by sex or BMI category. Exercise time along with sex and ethnicity explained roughly 60% of the variability in total daily energy expenditure (TDEE) while the association between exercise and time spent in moderate to vigorous PA or being sedentary was low or nonsignificant. Engagement in endurance exercise and sports contributed predominantly to the variability in energy expenditure and PA in nonoverweight participants. In overweight/obese participants engagement in resistance exercise and swimming contributed significantly to variability in TDEE. Current exercise recommendations focus primarily on aerobic exercise, but results of the present study suggest that nonweight-bearing exercises, such as resistance exercise and swimming, contribute significantly to the variability in TDEE in overweight/obese adults, which would make these types of activities viable options for exercise interventions.

Are Baby Boomers healthier than Generation X? A profile of Australia's working generations using National Health Survey data

Background

To determine differences in sociodemographic and health related characteristics of Australian Baby Boomers and Generation X at the same relative age.

Methods

The 1989/90 National Health Survey (NHS) for Boomers (1946–1965) and the 2007/08 NHS for Generation Xers (1966–1980) was used to compare the cohorts at the same age of 25–44 years. Generational differences for males and females in education, employment, smoking, physical activity, Body Mass Index (BMI), self-rated health, and diabetes were determined using Z tests. Prevalence estimates and p-values are reported. Logistic regression models examining overweight/obesity (BMI≥25) and diabetes prevalence as the dependent variables, with generation as the independent variable were adjusted for sex, age, education, physical activity, smoking and BMI(diabetes model only). Adjusted odds ratios (OR) and 95% confidence intervals are reported.

Results

At the same age, tertiary educational attainment was higher among Generation X males (27.6% vs. 15.2% p<0.001) and females (30.0% vs. 10.6% p<0.001). Boomer females had a higher rate of unemployment (5.6% vs. 2.5% p<0.001). Boomer males and females had a higher prevalence of “excellent” self-reported health (35.9% vs. 21.8% p<0.001; 36.3% vs. 25.1% p<0.001) and smoking (36.3% vs. 30.4% p<0.001; 28.3% vs. 22.3% p<0.001). Generation X males (18.3% vs. 9.4% p<0.001) and females (12.7% vs. 10.4% p = 0.015) demonstrated a higher prevalence of obesity (BMI>30). There were no differences in physical activity. Modelling indicated that Generation X were more likely than Boomers to be overweight/obese (OR:2.09, 1.77–2.46) and have diabetes (OR:1.79, 1.47–2.18).

Conclusion

Self-rated health has deteriorated while obesity and diabetes prevalence has increased. This may impact workforce participation and health care utilization in the future.

Baby boomers, obesity, and social change

SUMMARY

Baby boomers are currently in mid-life and over the next several decades they will swell the ranks of those aged 65 and over. Their entry into this age group will have a significant impact in a number of areas but particularly in relation to the type and extent of health services required. Obesity is a major health issue for this cohort as its members are significantly over-represented in both the overweight and obese categories compared to the rest of the population. In addition, they are significantly more likely to have multiple risk factors. This review considers how alterations to lifestyle, initiated by the rapid social changes of the last half century, might have contributed to obesity within this cohort. In providing this broad overview it focuses on how increased affluence and changes to everyday institutions have affected the cultures around food consumption. This includes a consideration of both the internal and external ways in which eating environments are now constructed. This review suggests that further research is needed to identify the factors which facilitate or constrain healthy ageing in the baby boom cohort. Research along these lines also needs to consider both macro- and micro-level changes to the social context within which these factors arise. This is essential as the high levels of obesity in this cohort may reflect both an individual and a structural lag in adapting lifestyles and policies to meet the needs of this very different social environment.:

Reconstruction of the drive underlying food intake and its control by leptin and dieting

The intake of food and the expenditure of calories is modelled by a system of differential equations. The state variables are the amount of calories stored in adipose tissue and the level of plasma leptin. The model has as input a drive that controls the intake of food. This drive consists of a collective of physiological and psychological incentives to eat or to stop eating. An individual based approach is presented by which the parameters of the system can be set using data of a subject. The method of analysis is fully worked out using weight data of two persons. The model is prone to extensions by transferring incentives being part of the input to the collection of state variables.

Long-Term Adherence to Health Behavior Change

The utility of lifestyle-based health promotion interventions is directly impacted by participant adherence to prescribed behavior changes. Unfortunately, poor adherence to behaviors recommended in lifestyle interventions is widespread, particularly over the long-term; thus, the "adherence problem" represents a significant challenge to the effectiveness of these interventions. The current review provides an overview of the adherence problem and describes a theoretical framework through which the factors that impact adherence can be understood. To further understand the difficulties individuals face when adhering to health behavior changes, we focus our discussion on challenges associated with adherence to lifestyle behaviors recommended for weight loss and healthy weight management (i.e., reductions in dietary intake and increases in physical activity). We describe strategies that improve long-term adherence to health behaviors related to healthy weight management, including the provision of extended care, skills training, improving social support, and strategies specific to maintaining changes in dietary intake and physical activity. Finally, we discuss difficulties involved in implementing long-term weight management programs and suggest practical solutions for providers.

The effects of overfeeding on spontaneous physical activity in obesity prone and obesity resistant humans

Despite living in an environment that promotes weight gain in many individuals, some individuals maintain a thin phenotype while self-reporting expending little or no effort to control their weight. When compared with obesity prone (OP) individuals, we wondered if obesity resistant (OR) individuals would have higher levels of spontaneous physical activity (SPA) or respond to short-term overfeeding by increasing their level of SPA in a manner that could potentially limit future weight gain. SPA was measured in 55 subjects (23 OP and 32 OR) using a novel physical activity monitoring system (PAMS) that measured body position and movement while subjects were awake for 6 days, either in a controlled eucaloric condition or during 3 days of overfeeding (1.4 × basal energy) and for the subsequent 3 days (ad libitum recovery period). Pedometers were also used before and during use of the PAMS to provide an independent measure of SPA. SPA was quantified by the PAMS as fraction of recording time spent lying, sitting, or in an upright posture. Accelerometry, measured while subjects were in an upright posture, was used to categorize time spent in different levels of movement (standing, walking slowly, quickly, etc.). There were no differences in SPA between groups when examined across all study periods (P > 0.05). However, 3 days following overfeeding, OP subjects significantly decreased the amount of time they spent walking (-2.0% of time, P = 0.03), whereas OR subjects maintained their walking (+0.2%, P > 0.05). The principle findings of this study are that increased levels of SPA either during eucaloric feeding or following short term overfeeding likely do not significantly contribute to obesity resistance although a decrease in SPA following overfeeding may contribute to future weight gain in individuals prone to obesity.

Brain structure predicts risk for obesity

The neurobiology of obesity is poorly understood. Here we report findings of a study designed to examine the differences in brain regional gray matter volume in adults recruited as either Obese Prone or Obese Resistant based on self-identification, body mass index, and personal/family weight history. Magnetic resonance imaging was performed in 28 Obese Prone (14 male, 14 female) and 25 Obese Resistant (13 male, 12 female) healthy adults. Voxel-based morphometry was used to identify gray matter volume differences between groups. Gray matter volume was found to be lower in the insula, medial orbitofrontal cortex and cerebellum in Obese Prone, as compared to Obese Resistant individuals. Adjusting for body fat mass did not impact these results. Insula gray matter volume was negatively correlated with leptin concentration and measures of hunger. These findings suggest that individuals at risk for weight gain have structural differences in brain regions known to be important in energy intake regulation, and that these differences, particularly in the insula, may be related to leptin.

Eating Motives and the Controversy over Dieting: Eating Less Than Needed versus Less Than Wanted

Anti-dieting sentiment has grown in recent years. Critics of restrained eating suggest that it evokes counter-regulatory responses that render it ineffective or even iatrogenic. However, restrained eaters are not in negative energy balance and overweight individuals show reduced eating problems when losing weight by dieting. A distinction is often drawn between physiological and psychological hunger, and neuroscience research has shown that there is a neurophysiological reality underlying this distinction. The brain has a homeostatic system (activated by energy deficits) and a hedonic system (activated by the presence of palatable food). The omnipresence of highly palatable food in the environment may chronically activate the hedonic appetite system, producing a need to actively restrain eating not just to lose weight but to avoid gaining it. Just as restricting energy intake below homeostatic needs produces physiological deprivation, restricting intake of palatable foods may produce "perceived deprivation" despite a state of energy balance. In summary, the motivation to eat more than one needs appears to be every bit as real, and perhaps every bit as powerful, as the motivation to eat when energy deprived.

AFestschriftfor Roland L. Weinsier: Nutrition Scientist, Educator, and Clinician1

Roland L. Weinsier, M.D., Dr.P.H., devoted himself to the fields of nutrition and obesity for more than 35 years. He contributed outstanding work related to the treatment of obesity through dietary and lifestyle change; metabolic/energetic influences on obesity, weight loss, and weight regain; body composition changes accompanying weight loss and regain; the health benefits and risks of weight loss; nutrition education for physicians; and nutrition support of sick patients. He served on the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) National Task Force on Prevention and Treatment of Obesity, as Chair of the University of Alabama at Birmingham's Department of Nutrition Sciences, and as Founder and Director of its NIDDK-funded Clinical Nutrition Research Center. He was a long-time and active member of NAASO, serving in the roles of Councilor, Publications Committee Chair, Continuing Medical Education Course Director, Public Relations Committee Chair, and Membership Committee Co-Chair, to name just a few. He was well respected as a staunch defender of NAASO's scientific integrity in these roles. Sadly, Roland Weinsier died on November 27, 2002. He will be missed and remembered by many as a revered and beloved teacher, mentor, healer, and scholar.

Geographic differences in physical education and adolescent BMI: have legal mandates made a difference?

The school environment is an ideal setting for healthy weight programming with adolescents. The federal government has reinforced the importance of school-based health promotion. The current study examined the preliminary influence of the 2006 school wellness policy requirement of the Child Nutrition and WIC Reauthorization Act (CNWICRA) on adolescent Body Mass Index (BMI) and physical education participation. Nationally representative data from the 2003 and 2007 Youth Risk Behavior Surveillance Survey (YRBSS) were used. The authors examined BMI percentile and physical education participation based on survey year and geographic region. Results suggest a slight decrease in BMI with no changes in physical education participation. A main effect for geographic region was found for both physical education participation and BMI percentile, while a geographic region-by-survey year interaction was discovered when analyzing BMI percentiles. Results suggest a need for continued investigation and may inform future healthy weight programming and geographically tailored wellness policies.

EUREKA

Recent research findings reveal that human bioenergetics belongs to the class of multi-loop nonlinear feedback systems—the same class of systems that system dynamics aims to study. In this paper the author aims to demonstrate the utility of utilizing simple—bathtub like—system dynamics models to gain insight into human weight and energy regulation and (in the process) help debunk widespread misconceptions that are hindering prevention and treatment efforts. Specifically, the author presents a series of models, starting with one that captures conventional wisdom about human energy regulation. This baseline model is critiqued and its limitations—and pitfalls—exposed through model experimentation. The model is then incrementally refined in a spiral of modeling-experimentation-learning steps, to arrive at a structure that integrates emerging (advanced) conceptualization(s) of human weight/energy regulation. In the concluding section, the author builds upon the insights gained from this modeling exercise to propose recommendations for obesity treatment and prevention.

Weight gain is associated with medial contact site of subthalamic stimulation in Parkinson's disease

The aim of our study was to assess changes in body-weight in relation to active electrode contact position in the subthalamic nucleus. Regular body weight measurements were done in 20 patients with advanced Parkinson's disease within a period of 18 months after implantation. T1-weighted (1.5T) magnetic resonance images were used to determine electrode position in the subthalamic nucleus and the Unified Parkinson's disease rating scale (UPDRS-III) was used for motor assessment. The distance of the contacts from the wall of the third ventricle in the mediolateral direction inversely correlated with weight gain (r = −0.55, p<0.01) and with neurostimulation-related motor condition expressed as the contralateral hemi-body UPDRS-III (r = −0.42, p<0.01). Patients with at least one contact within 9.3 mm of the wall experienced significantly greater weight gain (9.4±(SD)4.4 kg, N = 11) than those with both contacts located laterally (3.9±2.7 kg, N = 9) (p<0.001). The position of the active contact is critical not only for motor outcome but is also associated with weight gain, suggesting a regional effect of subthalamic stimulation on adjacent structures involved in the central regulation of energy balance, food intake or reward.

Patterns of physical activity and sedentary behavior in normal-weight, overweight and obese adults, as measured with a portable armband device and an electronic diary

BACKGROUND & AIMS

Accurate data on domain-specific physical activity and sedentary behavior among normal-weight, overweight and obese adults are scarce. This study described a comprehensive physical (in)activity profile and examined variations in activity across the week.

METHODS

Physical activity was measured in 442 Flemish adults (41.4 ± 9.8 years) for 7 days using the SenseWear Armband and an electronic diary. Differences in (in)activity between BMI subgroups were examined using one-way analyses of variance.

RESULTS

Physical activity level decreased with increasing BMI in men (1.77-1.46 MET) and women (1.67-1.31 MET). Sedentary time was higher in obese than normal-weight men (+1.09 h/day) and overweight and obese than normal-weight women (+1.04 and +1.88 h/day). Total hours of moderate-to-vigorous activity and bouts of moderate-to-vigorous activity were lower in overweight and obese than normal-weight subjects. The average duration of a sedentary bout and the number of breaks in sedentary time were only different between female BMI groups. The intensity of domain-specific activities decreased with increasing BMI. Activity patterns across the week differed between subgroups, with the difference most pronounced on Saturday for the male BMI groups.

CONCLUSIONS

This study described activity patterns among normal-weight, overweight and obese adults. The results should be used to design obesity prevention strategies.

Obesity: overview of an epidemic

The obesity epidemic in the United States has proven difficult to reverse. We have not been successful in helping people sustain the eating and physical activity patterns that are needed to maintain a healthy body weight. There is growing recognition that we will not be able to sustain healthy lifestyles until we are able to address the environment and culture that currently support unhealthy lifestyles. Addressing obesity requires an understanding of energy balance. From an energy balance approach it should be easier to prevent obesity than to reverse it. Further, from an energy balance point of view, it may not be possible to solve the problem by focusing on food alone. Currently, energy requirements of much of the population may be below the level of energy intake than can reasonably be maintained over time. Many initiatives are underway to revise how we build our communities, the ways we produce and market our foods, and the ways we inadvertently promote sedentary behavior. Efforts are underway to prevent obesity in schools, worksites, and communities. It is probably too early to evaluate these efforts, but there have been no large-scale successes in preventing obesity to date. There is reason to be optimistic about dealing with obesity. We have successfully addressed many previous threats to public health. It was probably inconceivable in the 1950s to think that major public health initiatives could have such a dramatic effect on reducing the prevalence of smoking in the United States. Yet, this serious problem was addressed via a combination of strategies involving public health, economics, political advocacy, behavioral change, and environmental change. Similarly, Americans have been persuaded to use seat belts and recycle, addressing two other challenges to public health. But, there is also reason to be pessimistic. Certainly, we can learn from our previous efforts for social change, but we must realize that our challenge with obesity may be greater. In the other examples cited, we had clear goals in mind. Our goals were to stop smoking, increase the use of seatbelts, and increase recycling. The difficulty of achieving these goals should not be minimized, but they were clear and simple goals. In the case of obesity, there is no clear agreement about goals. Moreover, experts do not agree on which strategies should be implemented on a widespread basis to achieve the behavioral changes in the population needed to reverse the high prevalence rates of obesity. We need a successful model that will help us understand what to do to address obesity. A good example is the recent HEALTHY study. This comprehensive intervention was implemented in several schools and aimed to reduce obesity by concentrating on behavior and environment. This intervention delivered most of the strategies we believe to be effective in schools. Although the program produced a reduction in obesity, this reduction was not greater than the reduction seen in the control schools that did not receive the intervention. This does not mean we should not be intervening in schools, but rather that it may require concerted efforts across behavioral settings to reduce obesity. Although we need successful models, there is a great deal of urgency in responding to the obesity epidemic. An excellent example is the effort to get menu labeling in restaurants, which is moving rapidly toward being national policy. The evaluation of this strategy is still ongoing, and it is not clear what impact it will have on obesity rates. We should be encouraging efforts like this, but we must evaluate them rigorously. Once we become serious about addressing obesity, it will likely take decades to reverse obesity rates to levels seen 30 years ago. Meanwhile, the prevalence of overweight and obesity remains high and quite likely will continue to increase.

Effective weight management practice: a review of the lifestyle intervention evidence

OBJECTIVES

Despite the existence of guidelines for obesity management, uncertainty remains as to what interventions comprise effective practice. This uncertainty could act as a barrier to busy health care professionals, who may lack the time and expertize to fully appraise the huge amount of literature that is published each year on obesity management. Therefore, the objectives of this review were to synthesize the available evidence, determine most effective and most promising practices for obesity management in adults, using an established methodology, and present this information according to its quality.

EVIDENCE ACQUISITION

This synthesis review was conducted from January 2009. A detailed search of relevant databases was conducted to September 2010. Most effective and promising practices were defined using the Canadian Best Practice Initiative Methodology Background Paper, with systematic reviews (with/without meta analysis) as the most rigorous methodology for developing recommendations that were deemed most effective (level 1), and non-systematic reviews for developing recommendations deemed as most promising (level 2). Literature was reviewed and classified across these two levels of rigor, and supplemented with primary studies to further refine recommendations.

RESULTS

Evidence from systematic reviews and meta-analyses was classified into three intervention themes or areas of context, in which more specific most effective and/or promising practice recommendations could be nested. These intervention themes were (1) targeted multi-component interventions for weight management, (2) dietary manipulation strategies and (3) delivery of weight management interventions, including health professional roles and method of delivery. Specific recommendations accompanied each theme.

CONCLUSIONS

This review highlights the value of multi-component interventions that are delivered over the longer term, and reinforces the role of health care professionals. The findings will help to inform evidence-based practice for health care practitioners involved in obesity management and prevention.