Social Status and Adolescent Physical Activity: Expanding the Insurance Hypothesis to Incorporate Energy Expenditure

The development and validation of the food insecurity physical activity concerns scale

Food insecurity - defined as having limited access to nutritious foods - is linked with obesity. Previous research has also shown that food insecurity is associated with lower levels of leisure-time physical activity (physical activity performed outside of essential activities). This association may occur in part due to concerns about preserving levels of energy during times of food shortage. Currently, no scale exists which measures this construct. Therefore, we aimed to develop and validate such a scale - the food insecurity physical activity concerns scale (FIPACS). Participants (N = 603, individuals with food insecurity = 108) completed an online survey, consisting of the FIPACS, the International Physical Activity Questionnaire short-form (IPAQ), the restraint subscale of the Dutch Eating Behaviour Questionnaire (DEBQ), the amotivation subscale of the Behaviour Regulation In Exercise Questionnaire-2 (BREQ-2), and the Behavioural Inhibition System/Behavioural Approach System Reactivity scale (BIS/BAS) to assess convergent and divergent validity. An exploratory factor analysis revealed a four-factor model of the FIPACS - namely 'Concerns relating to hunger', 'Concerns of replenishment and calories', 'Concerns of physiological effects of exercise' and 'Compensatory behaviours' which was verified through a confirmatory factor analysis. To assess test-retest reliability, 100 participants completed the FIPACS again two weeks later. The FIPACS had good internal, test-retest reliability and divergent validity. However, there was limited evidence of convergent validity. Future studies could incorporate this scale when investigating the association between food insecurity and physical activity.

Food insecurity as a cause of adiposity: evolutionary and mechanistic hypotheses

Food insecurity (FI) is associated with obesity among women in high-income countries. This seemingly paradoxical association can be explained by the insurance hypothesis, which states that humans possess evolved mechanisms that increase fat storage to buffer against energy shortfall when access to food is unpredictable. The evolutionary logic underlying the insurance hypothesis is well established and experiments on animals confirm that exposure to unpredictable food causes weight gain, but the mechanisms involved are less clear. Drawing on data from humans and other vertebrates, we review a suite of behavioural and physiological mechanisms that could increase fat storage under FI. FI causes short-term hyperphagia, but evidence that it is associated with increased total energy intake is lacking. Experiments on animals suggest that unpredictable food causes increases in retained metabolizable energy and reductions in energy expenditure sufficient to fuel weight gain in the absence of increased food intake. Reducing energy expenditure by diverting energy from somatic maintenance into fat stores should improve short-term survival under FI, but the trade-offs potentially include increased disease risk and accelerated ageing. We conclude that exposure to FI plausibly causes increased adiposity, poor health and shorter lifespan. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Role of physical activity and health-related fitness on self-confidence and interpersonal relations in 14-year-old adolescents from secondary school settings: DADOS study

BACKGROUND

The effect of physical activity (PA) and physical fitness (PF) on self-confidence and interpersonal relations in adolescents is uncertain.

AIM

To analyzed the associations of PA and PF with self-confidence and interpersonal relations in adolescents.

SAMPLE

A total of 268 (138 boys) adolescents (13.9 ± 0.3 years) from the DADOS study were included in the analysis.

METHODS

PA was evaluated using GENEActiv accelerometers and the health-related PF components by the ALPHA health-related fitness test battery. The levels of self-confidence and interpersonal relations were determined by the Behavior Assessment System for Children Level 3.

RESULTS

The associations of PA levels and PF components with self-confidence reported positive associations of moderate-vigorous PA (MVPA), standing long jump, and 20-m shuttle run (shuttle run test) tests (all p < 0.05), and negative association of 4 × 10-m shuttle run test (4 × 10-m test), but only the 4 × 10-m test remained significant in the adjusted model for the whole sample and only in boys (p ≤ 0.01) when analyzed by sex. Regarding interpersonal relations, positive associations of standing long jump and shuttle run test (all p < 0.05), and negative association of 4 × 10-m test were found in all the adolescents. The shuttle run test was associated with interpersonal relations in boys independently of confounders. PA levels were not associated with interpersonal relations.

CONCLUSION

A higher level of lower-limb muscle strength, speed-agility, and cardiorespiratory fitness might improve self-confidence and interpersonal relations in adolescents, but these relationships seem to be influenced by sex, body mass index, and pubertal status. Speed-agility and cardiorespiratory fitness seem to have a stronger impact on boys. MVPA may improve self-confidence in adolescents.

Physical Activity and Food Environments in and around Schools: A Case Study in Regional North-West Tasmania

A better understanding of the physical activity (PA) infrastructure in schools, the walkability of neighborhoods close to schools, and the food environments around schools, particularly in rural, socioeconomically challenged areas such as the North-West (NW) of Tasmania, could be important in the wider effort to improve the health of school-age children. Accordingly, this research aimed to assess PA resources, walkability, and food environments in and around schools in three socioeconomically disadvantaged, regional/rural Local Government Areas (LGAs) of Tasmania, Australia. A census of schools (including assessment of the PA infrastructure quality within school grounds), a walkability assessment, and a census of food outlets surrounding schools (through geospatial mapping) were executed. Most of the schools in the study region had access to an oval, basketball/volleyball/netball court, and free-standing exercise equipment. In all instances (i.e., regardless of school type), the quality of the available infrastructure was substantially higher than the number of incivilities observed. Most schools also had good (i.e., within the first four deciles) walkability. Numerous food outlets were within the walking zones of all schools in the study region, with an abundance of food outlets that predominantly sold processed unhealthy food.

The effects of experimentally manipulated social status and subjective social status on physical activity among Hispanic adolescents: An RCT

BACKGROUND

Low objective socioeconomic status (SES) and subjective social status (SSS), one's perceived social rank, are associated with obesity. This association may be due, in part, to social status-related differences in energy expenditure. Experimental studies are needed to assess the extent to which SES and SSS relate to energy expenditure.

OBJECTIVE

Assess the effects of experimentally manipulated social status and SSS on moderate-to-vigorous physical activity (MVPA) and sedentary behaviour.

METHODS

One hundred thirty-three Hispanic adolescents aged 15-21 were randomized to a high or low social status position, facilitated through a rigged game of Monopoly™. SSS was assessed with MacArthur Scales. Post-manipulation 24-h MVPA and sedentary behaviour were assessed via accelerometry. Analyses were conducted with general linear regression models.

RESULTS

Experimentally manipulated social status did not significantly affect the total time spent in MVPA or sedentary behaviour; however, identifying as low SSS was significantly associated with less MVPA (p = 0.0060; 18.76 min less).

CONCLUSIONS

Tewnty-four-hour MVPA and sedentary behaviour are not affected by an acute experimental manipulation of social status. However, low SSS, independent of SES, was associated with clinically significant differences in MVPA. SSS may be a better predictor of MVPA than SES among Hispanic adolescents, potentially influencing obesity, and other health-related outcomes.

A Refined Method for Studying Foraging Behaviour and Body Mass in Group-Housed European Starlings

Simple Summary

Small birds such as European starlings respond rapidly to environmental challenges by losing or gaining weight. Laboratory studies of these birds are therefore useful for understanding how the environment affects body weight. However, practical constraints including the need to catch birds frequently for weighing has meant that birds are often housed alone in small cages for such studies. Such conditions are unnatural and are likely to cause stress. Consequently, the data obtained from these studies are unrepresentative of wild birds. Here, we describe a novel technology based on smart feeders that permits continuous recording of foraging behaviour and body masses from starlings housed in groups in large indoor aviaries that permit more natural behaviour. We show that the birds quickly learn to use the feeders and that the system delivers detailed real-time data on foraging behaviour and body mass, without the need for frequent catching. The data obtained allowed us to study how the foraging decisions that a bird makes within a single day affect its body weight that day. These improvements in the quality of the data that we are able to collect will help inform our understanding of the environmental causes of weight gain and obesity.

Abstract

Laboratory experiments on passerine birds have been important for testing hypotheses regarding the effects of environmental variables on the adaptive regulation of body mass. However, previous work in this area has suffered from poor ecological validity and animal welfare due to the requirement to house birds individually in small cages to facilitate behavioural measurement and frequent catching for weighing. Here, we describe the social foraging system, a novel technology that permits continuous collection of individual-level data on operant foraging behaviour and body mass from group-housed European starlings (Sturnus vulgaris). We report on the rapid acquisition of operant key pecking, followed by foraging and body mass data from two groups of six birds maintained on a fixed-ratio operant schedule under closed economy for 11 consecutive days. Birds gained 6.0 ± 1.2 g (mean ± sd) between dawn and dusk each day and lost an equal amount overnight. Individual daily mass gain trajectories were non-linear, with the rate of gain decelerating between dawn and dusk. Within-bird variation in daily foraging effort (key pecks) positively predicted within-bird variation in dusk mass. However, between-bird variation in mean foraging effort was uncorrelated with between-bird variation in mean mass, potentially indicative of individual differences in daily energy requirements. We conclude that the social foraging system delivers refined data collection and offers potential for improving our understanding of mass regulation in starlings and other species.

Relative contributions of health behaviours versus social factors on perceived and objective weight status in Canadian adolescents

OBJECTIVES

Public health interventions for adolescent "obesity prevention" have focused predominantly on individualistic health behaviours (e.g., diet and physical activity) at the expense of recognizing body weight diversity and the array of social factors (e.g., stigma and discrimination of marginalized identities) that may be linked to weight status. Research is needed to examine the extent to which individualistic health behaviours versus social factors contribute to weight status in adolescents. As such, the aim of this study was to investigate the relative contribution of individualistic health behaviours versus social factors to objective and perceptual indices of weight status.

METHODS

Cross-sectional survey data were collected as part of the Toronto Public Health Student Survey and comprised students 12 to 19 years of age (N = 5515). Measures included perceived and objective weight status, social and demographic factors (e.g., gender, sexual orientation, school connectedness), and health behaviours (e.g., physical activity, nutritious consumption).

RESULTS

Findings from latent variable regression models partially supported hypotheses, whereby social factors (i.e., age, sex, socio-economic access, sexual minority status) contribute similar amounts of variance, or relatively more variance in weight indices, compared to health behaviours (e.g., physical activity, nutritious consumption).

CONCLUSION

Contrary to traditional views of adolescent weight status, physical activity (i.e., school-based, individual, active transport) and nutritious consumption (i.e., fruits, vegetables, milk) were not associated with weight status, when considering social factors. These findings challenge the utility of public health approaches that target individualistic behaviours as critical risk factors in "obesity prevention" efforts in adolescence.

Experimentally Manipulated Low Social Status and Food Insecurity Alter Eating Behavior Among Adolescents: A Randomized Controlled Trial

OBJECTIVE

This randomized trial experimentally manipulated social status to assess effects on acute eating behavior and 24-hour energy balance.

METHODS

Participants (n = 133 Hispanics; age 15-21 years; 60.2% females) were randomized to low social status ("LOW") or high social status ("HIGH") conditions in a rigged game of Monopoly (Hasbro, Inc.). Acute energy intake in a lunchtime meal was measured by food scales. Twenty-four-hour energy balance was assessed via summation of resting metabolic rate (metabolic cart), physical activity energy expenditure (accelerometer), thermic effect of food, and subtraction of twenty-four-hour energy intake (food diary).

RESULTS

In the total sample, no significant differences were observed by study condition at lunchtime. LOW females consumed a greater percent of lunchtime daily energy needs (37.5%) relative to HIGH females (34.3%); however, this difference was not statistically significant (P = 0.291). In males, however, LOW consumed significantly less (36.5%) of their daily energy needs relative to HIGH males (45.8%; P = 0.001). For 24-hour energy balance, sex differences were nearly significant (P = 0.057; LOW females: surplus +200 kcal; HIGH males: surplus +445 kcal). Food-insecure individuals consumed a nearly significant greater lunchtime percent daily energy than those with food security (40.7% vs. 36.3%; P = 0.0797).

CONCLUSIONS

The data demonstrate differential acute and 24-hour eating behavior responses between Hispanic male and female adolescents in experimentally manipulated conditions of low social status.

Objective and subjective socioeconomic status associated with metabolic syndrome severity among African American adults in Jackson Heart Study

PURPOSE

To assess independent associations between objective socioeconomic status (OSS) and subjective social status (SSS) with metabolic syndrome (MetS) severity and indicators among African American (AA) adults in the Jackson Heart Study (JHS) at baseline (2000-2004) and eight-year follow-up (2009-2013).

METHODS

Participants included 1724 AA adults from the JHS cohort (64.4 % women; mean age 53.4 ± 11.8). Associations of OSS (annual household income and school years completed) and SSS (measured with MacArthur Scales) with sex- and race/ethnic-specific MetS severity Z-score were examined after adjustment for demographics and MetS risk factors (i.e., nutrition, physical activity, smoking status, alcohol consumption, and depressive symptoms) at baseline and eight-year follow-up.

PRINCIPAL RESULTS

Independent of OSS, demographic, psychosocial, and lifestyle factors, individuals with lower US-society SSS had more severe MetS at baseline. A significant interaction existed between sex and US-society SSS such that women with lower perceived social status had more severe MetS severity at baseline, and for every one unit increase in US-society SSS, MetS severity Z-score is estimated to decrease by 0.04. Components of MetS driving the relationship between US-society SSS and MetS severity at baseline were the inverse associations of SSS with glucose levels and the positive associations of SSS with HDL-C. Physical activity was independently associated with MetS severity at baseline, but not at eight-year follow-up.

MAJOR CONCLUSIONS

Though subjective and objective measures of social status are independently associated with cardiometabolic risk factors and MetS severity among AA adults, SSS may be a stronger predictor of MetS severity than OSS, particularly among women. SSS should be considered in conjunction with OSS when exploring social determinants of cardiometabolic health.

Food-Insecure Women Eat a Less Diverse Diet in a More Temporally Variable Way: Evidence from the US National Health and Nutrition Examination Survey, 2013-4

Food insecurity is associated with high body weight amongst women, but not men, in high-income countries. Previous research using food recalls suggests that the total energy intake of food-insecure women is not elevated, though macronutrient composition may differ from that of food-secure women. There is limited evidence on temporal patterns of food consumption. Here, we used food recalls from women in the 2013-4 cycle of the National Health and Nutrition Examination Survey (NHANES, n = 2798) to characterise temporal patterns of food consumption in relation to food insecurity. Compared to the food-secure, food-insecure women had more variable time gaps between eating; ate a smaller and less variable number of distinct foods at a time; were more variable from day to day in their time of first consumption; were more variable from day to day in the number of times they ate; and consumed relatively more carbohydrate, less protein, and less fibre. However, their overall energy intake was no higher. Food-insecure women had higher BMIs (2.25 kg/m²), and around 15% of the BMI difference between food-insecure and food-secure women was accounted for by their more variable time gaps between eating, their lower diversity of foods, and their lower fibre consumption. Food insecurity is associated with measureable differences in the temporal pattern of food consumption, and some of these differences shed light on how food-insecure women come to have higher body weights.