Daily Dietary Protein Distribution Does Not Influence Changes in Body Composition During Weight Loss in Women of Reproductive Years with Overweight or Obesity: A Randomized Controlled Trial

BACKGROUND

Preservation of fat-free mass (FFM) during intentional weight loss is challenging yet important to maintain a resting metabolic rate. A balanced protein distribution of 25-30 g per meal improves 24-h muscle protein synthesis, which may promote FFM maintenance and greater reductions in fat mass (FM) during weight loss in women.

OBJECTIVES

We aimed to determine whether the daily dietary protein distribution pattern during energy restriction influences changes in body composition in women of reproductive age. We hypothesized that evenly distributing protein across meals compared with the usual intake pattern of consuming most of the protein at the dinner meal would be superior in preserving FFM while reducing FM during weight loss.

METHODS

Healthy women (n = 43) aged 20-44 y with a BMI of 28-45 kg/m2 completed a randomized parallel feeding study testing 2 patterns of daily protein intake (even distribution across all meals compared with a skewed distribution with most protein consumed at the evening meal). Participants completed an 8-wk controlled 20% energy restriction (all foods provided), followed by an 8-wk self-choice phase in which participants were asked to maintain a similar diet and dietary pattern when purchasing and consuming their own foods. Body composition was measured at baseline, week 8, and week 16. Data were analyzed using mixed models. Statistical significance was set at P < 0.05. Data are presented as differences in least squares means ± SE.

RESULTS

No significant main effects of group or group-by-time interactions were observed. All measures exhibited the main effect of time (P < 0.001). Overall, body weight, FFM, FM, and body fat percentage decreased 5.6 ± 0.4, 1.0 ± 0.2, 4.6 ± 0.4 kg, and 2.3 ± 0.2%, respectively, during this 16-wk study.

CONCLUSION

Daily dietary protein distribution at a fixed protein level does not appear to influence changes in body composition during weight loss in women of reproductive age.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE WHERE IT WAS OBTAINED

NCT03202069 https://classic.

CLINICALTRIALS

gov/ct2/show/NCT03202069.

Chokeberry reduces inflammation in human preadipocytes

Chokeberry, Aronia melanocarpa, is an indigenous fruit from North America used as food and to prevent chronic disease by Indigenous Peoples. The objective of this study was to test anti-inflammatory effects of anthocyanin on palmitic acid (PA)-induced IL-6 gene expression, IL-6 DNA methylation, and histone (H3) acetylation. Additionally, we examined effects of anthocyanins Cyanidin-3-O-galactoside (C3Gal) and Cyanidin-3-glucoside (C3G) on IL-6 gene expression. Human primary pre-adipocytes were treated with chokeberry juice extract (CBE), C3Gal or C3G in the presence or absence of PA or lipopolysaccharide (LPS). CBE inhibited LPS- and PA-induced IL-6 mRNA expression (p < 0.0001), while C3G and C3Gal had smaller effects. Human IL-6 promoter DNA methylation was increased (p = 0.0256) in CBE treated cells compared to control. Histone H3 acetylations were not affected by CBE or PA treatment. These data indicate that CBE epigenetically reduced PA-induced inflammation by regulating IL-6 DNA methylation without affecting histone modifications in human preadipocyte cells.

Effect of source on trust of pulse nutrition information and perceived likelihood of following dietary guidance

OBJECTIVE

The purpose of the present study was to examine how information source (control-no source, U.S. Department of Agriculture (USDA), fictitious hospital, or fictitious social media) impacts perceptions of diet information.

METHODS AND MEASURES

Participants (N = 537) completed an online survey in which they viewed one flyer containing dietary information and guidance on consuming pulses. The purported source of the flyer information was manipulated to create the 4 conditions. Participants rated the flyer in terms of perceived accuracy, trustworthiness, reliability, desirability for learning more from the source, and likelihood of following the advice. Attitudes, perceived control and norms, and past behavior were used to measure components of the Theory of Planned Behavior (TPB).

RESULTS

ANOVA results indicated that the USDA and hospital sources were perceived as more accurate, trustworthy, reliable, and more desirable to learn more from relative to control and social media. There were no differences in likelihood of following guidance depending on source. Multiple regression showed that measures of the TPB were predictors of likelihood of following advice.

CONCLUSION

Overall, these findings suggest that trust in the source of information does not influence perceived likelihood of following dietary recommendations for pulses.

Biochemical Validation of a Self-Administered Carotenoid Intake Screener to Assess Carotenoid Intake in Nonobese Adults

Background

Epidemiological studies have demonstrated an association between carotenoid intake and health. However, an accurate measurement of carotenoid intake is challenging. FFQ is the most commonly used dietary assessment method and is typically composed of 100-200 items. However, the greater participant burden that accompanies a more detailed FFQ provides only a marginal gain in accuracy. Therefore, a brief validated carotenoid intake screener is needed.

Objectives

To conduct secondary analysis evaluating the validity of a newly developed 44-item carotenoid intake screener from The Juice Study: Sensitivity of Skin Carotenoid Status to Detect Change in Intake (NCT03202043) against corresponding plasma carotenoid concentrations (primary) and skin carotenoids (secondary) in nonobese Midwestern American adults.

Methods

Healthy adults (n = 83; 25 men and 58 women) aged 18-65 y (mean age, 32 ± 12 y) with a BMI (in kg/m2) of 18.5-29.9 (mean BMI, 25 ± 3) were recruited between 25 April 2018 and 28 March 2019. Participants completed the carotenoid intake screener weekly during the 8-wk parent study. Plasma carotenoid concentrations were assessed at weeks 0, 4, and 8 using HPLC. Skin carotenoids were assessed weekly using pressure-mediated reflection spectroscopy (RS). Correlation matrices from mixed models were used to determine the correlation between carotenoid intake and plasma and skin carotenoids over time.

Results

The total carotenoid intake, as determined by the carotenoid intake screener, correlated with both the plasma total carotenoid concentration (r = 0.52; P < 0.0001) and the RS-assessed skin carotenoid concentration (r = 0.43; P < 0.0001). Correlations between reported intake and plasma concentrations of α-carotene (r = 0.40; P = 0.0002), cryptoxanthin (r = 0.28; P = 0.0113), and lycopene (r = 0.33; P = 0.0022) were also observed.

Conclusions

The results of this study demonstrate an acceptable relative validity of the carotenoid intake screener to assess total carotenoid intake in adults classified as those having a healthy body or those with overweight.

Sensitivity of Pressure-Mediated Reflection Spectroscopy to Detect Changes in Skin Carotenoids in Adults Without Obesity in Response to Increased Carotenoid Intake: A Randomized Controlled Trial

BACKGROUND

The sensitivity of commercially available devices to detect changes in skin carotenoids is not known.

OBJECTIVES

We aimed to determine the sensitivity of pressure-mediated reflection spectroscopy (RS) to detect changes in skin carotenoids in response to increasing carotenoid intake.

METHODS

Nonobese adults were randomly assigned to a control (water; n = 20; females = 15 (75%); mean age: 31 ± 3 (SE) y; mean BMI: 26 ± 1 kg/m²) or one of 3 carotenoid intake levels: 1) LOW - 13.1 mg; n = 22; females = 18(82%); age: 33 ± 3 y; BMI: 25 ± 1 kg/m²; 2) MED - 23.9 mg; n = 22; females = 17 (77%); age: 30 ± 2 y; BMI: 26 ± 1 kg/m²); or 3) HIGH - 31.0 mg; n = 19; females = 9 (47%); age: 33 ± 3 y; BMI: 24 ± 1 kg/m². A commercial vegetable juice was provided daily to ensure that the additional carotenoid intake was achieved. Skin carotenoids (RS intensity [RSI]) were measured weekly. Plasma carotenoid concentrations were assessed at wk 0, 4, and 8. Mixed models were used to test the effect of treatment, time, and their interaction. Correlation matrices from mixed models were used to determine the correlation between plasma and skin carotenoids.

RESULTS

A correlation was observed between skin and plasma carotenoids (r = 0.65; P < 0.001). Skin carotenoids were greater than baseline starting at week 1 in the HIGH (290 ± 20 vs. 321 ± 24 RSI; P ≤ 0.01), week 2 in the MED (274 ± 18 vs. 290 ± 23 RSI; P ≤ 0.03), and week 3 in the LOW (261 ± 18 vs. 288 ± 15 RSI; P ≤ 0.03). Compared with control, differences in skin carotenoids were observed starting at week 2 in the HIGH ([268 ± 16 vs. 338 ± 26 RSI; P ≤ 0.01] except for week 3 [287 ± 20 vs. 335 ± 26 RSI; P = 0.08]) and week 6 in the MED (303 ± 26 vs. 363 ± 27 RSI; P ≤ 0.03). No differences were observed between the control and LOW.

CONCLUSIONS

These findings demonstrate that RS can detect changes in skin carotenoids in adults without obesity when daily carotenoid intake is increased by 13.1 mg for a minimum of 3 wk. However, a minimum difference in intake of 23.9 mg of carotenoids is needed to detect group differences. This trial was registered at ClinicalTrials.gov as NCT03202043.

Seasonal Changes in Midlife Women'S Percentage Body Fat: A 1-Year Cohort Study

OBJECTIVE

The purpose of this longitudinal, observational study was to examine whether age and seasonal changes in sedentary activity (sedAct), moderate-to-vigorous physical activity (MVPA), and energy intake (EI) predict changes in body composition among midlife women. We hypothesized that reductions in MVPA and increases in sedAct and EI in winter, along with greater baseline age would predict increases in percentage body fat (%BF) across seasons.

DESIGN

This study used a longitudinal, within-subjects design. Setting: This study took place in Grand Forks, North Dakota.

PARTICIPANTS

Participants included 52 midlife women (aged 40-60 years) who were observed over the course of one year.

MEASUREMENTS

Percentage body fat measures were obtained via whole body Dual Energy X-ray absorptiometry. Participants were scanned once per season. We measured EI using the ASA24®. We used a GTX3 accelerometer to measure physical activity. Each season, participants wore the monitors for 7 days, 12 hours per day. All measures began in summer.

RESULTS

Results of hierarchical multiple regression (MR) analyses showed that age increases (β = 0.310, p = 0.021) and summer-to-fall increases in EI (β = 0.427, p = 0.002) predicted seasonal increases in %BF (R2 = .36, F(5, 42)= 4.66, p = 0.02). Changes in MVPA and sedAct were not significant predictors. Repeated measures ANCOVA revealed that summer (M = 37.7263, 95% CI [35.8377, 39.6149]) to winter (M = 38.1463, 95% CI [36.1983, 40.0942]) increases in %BF are not reversed by spring (M = 37.8761, 95% CI [35.9365, 39.8157]).

CONCLUSIONS

To minimize increases in %BF and maintain health, midlife women, particularly older women, should be encouraged to pay extra attention to their diet in the fall months.

The influence of active video game play upon physical activity and screen-based activities in sedentary children

Background

Few children meet physical activity recommendations, partly due to the prevalence of screen-based sedentary activities. Active video game (AVG) play produces light to moderate physical activity. Yet, providing children access to AVG does not increase physical activity, possibly because children who play AVG may also tend towards sedentary screen-based activities. How multiple days of AVG play influences children’s choice of other activities is not yet known.

Purpose

To examine how AVG influences children’s physical activity, sedentary screen-based activities, and other alternative activities.

Methods

Sedentary children (N = 49) played AVG 3 times/week and sedentary video games (SVG) ad libitum for 6 weeks, followed by 4 weeks of ad libitum play of both AVG and SVG. Participants wore an activity monitor for 7 days and completed a 24-hour activity recall on 4 randomly selected days at baseline, week 6, and week 10.

Results

AVG play increased during the intervention (p < 0.01). Light activity and SVG play both decreased baseline to 10 weeks (p = 0.006) and 6 to 10 weeks (p = 0.017). Non-SVG sedentary behavior increased from baseline to 10 weeks (p = 0.005) and 6 to 10 weeks (p = 0.007). Changes over time were not observed in physical activity, or recall-measured active play, social activities, other hobbies, television or computer/phone use.

Conclusion

AVG play did not change children’s objectively-measured physical activity or subjectively measured active play. SVG time was substituted with other sedentary behaviors. AVG did not increase time engaged in SVG or screen-based devices.

Corrigendum: Lipidomic Analysis of TRPC1 Ca2+-Permeable Channel-Knock Out Mouse Demonstrates a Vital Role in Placental Tissue Sphingolipid and Triacylglycerol Homeostasis Under Maternal High-Fat Diet

[This corrects the article DOI: 10.3389/fendo.2022.854269.].

Lipidomic Analysis of TRPC1 Ca2+-Permeable Channel-Knock Out Mouse Demonstrates a Vital Role in Placental Tissue Sphingolipid and Triacylglycerol Homeostasis Under Maternal High-Fat Diet

The transient receptor potential canonical channel 1 (TRPC1) is a ubiquitous Ca²⁺-permeable integral membrane protein present in most tissues, including adipose and placenta, and functionally regulates energetic homeostasis. We demonstrated that elimination of TRPC1 in a mouse model increased body adiposity and limited adipose accumulation under a high fat diet (HFD) even under conditions of exercise. Additionally, intracellular Ca²⁺ regulates membrane lipid content via the activation of the protein kinase C pathway, which may impact placental membrane lipid content and structure. Based upon this we investigated the effect of HFD and TRPC1 elimination on neutral lipids (triacylglycerol and cholesteryl ester), membrane lipids (phosphatidylcholine and phosphatidylethanolamine), and other multifunctional lipid species (unesterified cholesterol, sphingomyelins, ceramides). The concentration of unesterified cholesterol and sphingomyelin increased with gestational age (E12.5 to E 18.5.) indicating possible increases in plasma membrane fluidity. Diet-dependent increases ceramide concentration at E12.5 suggest a pro-inflammatory role for HFD in early gestation. TRPC1-dependent decreases in cholesterol ester concentration with concomitant increases in long-chain polyunsaturated fatty acid -containing triacylglycerols indicate a disruption of neutral lipid homeostasis that may be tied to Ca²⁺ regulation. These results align with changes in lipid content observed in studies of preeclamptic human placenta.

Effects of Exercise Training on Resting Testosterone Concentrations in Insufficiently Active Men: A Systematic Review and Meta-Analysis

ABSTRACT

Potter, NJ, Tomkinson, GR, Dufner, TJ, Walch, TJ, Roemmich, JN, Wilson, PB, and Fitzgerald, JS. Effects of exercise training on resting testosterone concentrations in insufficiently active men: a systematic review and meta-analysis. J Strength Cond Res 35(12): 3521-3528, 2021-The anabolic hormone testosterone plays a pivotal role in the healthy aging of men and tends to decline with age. The aims of this systematic review and meta-analysis were 2-fold: (a) to evaluate the effect of exercise training on resting total testosterone concentration in insufficiently active, apparently healthy men and (b) to determine whether the effects of exercise training differed by training mode, age, body mass status, or testosterone measure. Electronic databases (MEDLINE, Scopus, CINAHL, and SPORTDiscus) were systematically searched (up to and including October 22, 2020) for peer-reviewed randomized controlled trials (RCTs) meeting the following criteria: population (insufficiently active, apparently healthy men aged ≥18 years), intervention (exercise training [any modality at intensity of ≥4 metabolic equivalents] lasting a minimum of 4 weeks), control (insufficiently active men), and outcome (resting total testosterone concentration). Intervention effects, weighted by the inverse of the pooled variance, were calculated relative to the control group as standardized mean differences (SMDs). Eleven RCTs, representing 421 insufficiently active, apparently healthy men aged 19-75 years across 16 intervention groups who participated in aerobic, resistance, or combined training lasting a median of 12 weeks, were included in the analysis. Overall, exercise training had a negligible effect on resting total testosterone concentration (mean SMD [95% CI]: 0.00 [-0.20 to 0.20]). Subgroup analyses indicated that the effect of exercise training was not significantly affected by training mode, age, body mass status, or testosterone measure. Exercise training does not seem to affect resting total or free testosterone concentration in insufficiently active, eugonadal men.

Consumption of Dietary Guidelines for Americans types and amounts of vegetables increases mean Subjective Happiness Scale scores: A randomized controlled trial

BACKGROUND

The health benefits of diets rich in fruits and vegetables (FV) are well established. Recent observational and intervention research suggests that FV consumption may also exert a positive effect on psychological well-being.

OBJECTIVE

This study aimed to assess changes in mean Subjective Happiness Scale (SHS) scores in response to consuming DGA recommended types and amounts of vegetables. It was hypothesized that increased vegetable consumption would increase mean SHS scores.

DESIGN

This study investigated a secondary outcome of a randomized, parallel, non-blinded controlled trial with a 1:1 allocation ratio to a provided vegetable intervention or attention control group.

PARTICIPANTS/SETTING

Men and women (n=75) aged 18-65 years, body mass index ≥25 kg/m², with low habitual vegetable consumption were recruited from Grand Forks, ND, December 2016 to January 2018, for this community-based study.

INTERVENTION

The vegetable intervention consisted of an 8-week feeding phase during which participants were provided with vegetables in DGA recommended types and amounts. The attention control group was not provided vegetables but completed the same testing schedule as the vegetable intervention group.

MAIN OUTCOME MEASURE

Mean SHS scores were assessed before and after the intervention.

STATISTICAL ANALYSES

Mean SHS scores were analyzed using a 2-way factorial mixed linear model analysis of variance.

RESULTS

A significant interaction between treatment and visit (P=0.015) revealed greater mean SHS scores at week 8 than at baseline in the vegetable intervention group (+0.23 ± 0.11 (mean difference ± standard error of the difference) but no change in the attention control group (-0.15 ± 0.11).

CONCLUSIONS

Greater mean SHS scores were observed after increasing vegetable consumption to meet DGA recommendations, suggesting that adhering to DGA vegetable guidance may help promote psychological well-being.

Increasing Vegetable Intake Decreases Urinary Acidity and Bone Resorption Marker in Overweight and Obese Adults: An 8-Week Randomized Controlled Trial

BACKGROUND

Controlled intervention trials are needed to confirm a positive association from epidemiological studies between vegetable consumption and bone health.

OBJECTIVE

We investigated whether providing vegetables at the Dietary Guidelines for Americans (DGA) recommended amount affects excretion of acid and calcium in urine and bone turnover markers in serum in adults with low vegetable intake.

METHODS

In total, 102 adults (19 males and 83 females, age 18-65 y, BMI ≥25 kg/m2) consuming ≤1 serving of vegetables (128 g raw leafy or 64 g cooked vegetables) per d were recruited in a 2-arm, parallel, randomized, controlled, and community-based 8-wk feeding intervention trial. The 2 arms included a vegetable intervention (VI) during which participants received extra vegetables (∼270 g/d) and an attention control (CON) group that conducted only the testing visits. Measurements included nutrient intake, plasma carotenoids, and bone-related markers in serum and urine. Differences between CON and VI at week 8 were tested using the ANCOVA with baseline values as a covariate.

RESULTS

Compared with CON, carotenoid intake (mean ± SD) was higher (6.4 ± 3.4 compared with 2.0 ± 1.2 mg/d) (P < 0.01) and dietary potential renal acid load was lower (20 ± 13 compared with 3.4 ± 14 mEq/d) (P < 0.01) in VI. Compared with CON at week 8, urine titratable acid and Mg were 24 and 26% lower, respectively, while urine pH was 3% greater (P < 0.05) and serum C-terminal telopeptide of type I collagen (CTX) was 19% lower in VI. There were no group differences in serum concentrations of propeptide of type 1 procollagen and tartrate-resistant acid phosphatase or urinary excretion of deoxypyridinoline and CTX.

CONCLUSIONS

Consumption of vegetables at the DGA-recommended amount by adults with low vegetable intake potentially benefits bone health. This trial was registered at clinicaltrials.gov as NCT02585102.

What Sets Physically Active Rural Communities Apart from Less Active Ones? A Comparative Case Study of Three US Counties

BACKGROUND

Rural US communities experience health disparities, including a lower prevalence of physical activity (PA). However, "Positive Deviants"-rural communities with greater PA than their peers-exist. The purpose of this study was to identify the factors that help create physically active rural US communities.

METHODS

Stakeholder interviews, on-site intercept interviews, and in-person observations were used to form a comparative case study of two rural counties with high PA prevalence (HPAs) and one with low PA prevalence (LPA) from a southern US state, selected based on rurality and adult PA prevalence. Interview transcripts were inductively coded by three readers, resulting in a thematic structure that aligned with a Community Capital Framework, which was then used for deductive coding and analysis.

RESULTS

Fifteen stakeholder interviews, nine intercept interviews, and on-site observations were conducted. Human and Organizational Capital differed between the HPAs and LPA, manifesting as Social, Built, Financial, and Political Capital differences and a possible "spiraling-up" or cyclical effect through increasing PA and health (Human Capital), highlighting a potential causal model for future study.

CONCLUSIONS

Multi-organizational PA coalitions may hold promise for rural PA by directly influencing Human and Organizational Capital in the short term and the other forms of capital in the long term.

Vitamin D Awareness and Intake in Collegiate Athletes

ABSTRACT

Leitch, BA, Wilson, PB, Ufholz, KE, Roemmich, JN, Orysiak, J, Walch, TJ, Short, SE, and Fitzgerald, JS. Vitamin D awareness and intake in collegiate athletes. J Strength Cond Res 35(10): 2742-2748, 2021-Poor vitamin D status is a risk factor for negative health and performance outcomes in athletes, but little is known about how athletes' awareness and beliefs about vitamin D affect their consumption of vitamin D. This observational study investigated awareness of vitamin D for health and performance among collegiate athletes and evaluated the association of vitamin D awareness with its dietary intake. Fifty-two female and 29 male Division I collegiate athletes completed an online vitamin D awareness and dietary intake questionnaire between November 1, 2015, and January 30, 2016. Median intake of vitamin D was 330 International Units (IU), which is below the recommended daily allowance (RDA) of 600 IU, but was greater in male athletes (693 IU) than female athletes (263 IU, p < 0.01). The RDA for vitamin D was met by 62% of men and 30% of women. Athletes responded that vitamin D "probably" or "definitely" will play a role in their health (88.9%) and athletic performance (71.6%). However, only 23.4 and 28.4% of athletes reported concern for their vitamin D levels or believed that they were at risk for deficiency, respectively. Results showed small-to-moderate, positive correlations (r = 0.28-0.495, p < 0.05) between aspects of vitamin D awareness and vitamin D intake, particularly with supplemental forms of vitamin D. Given the lack of awareness concerning risk of vitamin D deficiency, and the links between aspects of vitamin D awareness and vitamin D intake, nutritional education programs designed to increase vitamin D awareness in athletes may be an effective strategy to reduce deficiency.

Environmental Factors Associated with Physical Activity in Rural U.S. Counties

Background: Rural U.S. adults’ prevalence of meeting physical activity (PA) guidelines is lower than urban adults, yet rural-urban differences in environmental influences of adults’ PA are largely unknown. The study’s objective was to identify rural-urban variations in environmental factors associated with the prevalence of adults meeting PA guidelines. Methods: County-level data for non-frontier counties (n = 2697) were used. A five-category rurality variable was created using the percentage of a county’s population living in a rural area. Factor scores from Factor Analyses (FA) were used in subsequent Multiple Linear Regression (MLR) analyses stratified by rurality to identify associations between environmental factor scores and the prevalence of males and females meeting PA guidelines. Results: FA revealed a 13-variable, four-factor structure of natural, social, recreation, and transportation environments. MLR revealed that natural, social, and recreation environments were associated with PA for males and females, with variation by sex for social environment. The natural environment was associated with PA in all but urban counties; the recreation environment was associated with PA in the urban counties and the two most rural counties. Conclusions: Variations across the rural-urban continuum in environmental factors associated with adults’ PA, highlight the uniqueness of rural PA and the need to further study what succeeds in creating active rural places.

Consumption of a Variety of Vegetables to Meet Dietary Guidelines for Americans' Recommendations Does Not Induce Sensitization of Vegetable Reinforcement Among Adults with Overweight and Obesity: A Randomized Controlled Trial

BACKGROUND

Food reinforcement, or the motivation to obtain food, can predict choice and consumption. Vegetable consumption is well below recommended amounts for adults, so understanding how to increase vegetable reinforcement could provide valuable insight into how to increase consumption.

OBJECTIVES

We sought to determine whether daily consumption of the Dietary Guidelines for Americans (DGA) recommendations for vegetable intake induces sensitization of vegetable reinforcement in adults with overweight and obesity.

METHODS

Healthy adults with a BMI ≥ 25 kg/m2 who consumed ≤1 cup-equivalent of vegetables/day were randomly assigned to a vegetable intervention (VI; n = 55) or an attention control (AC; n = 55) group. The VI consisted of the daily provision of vegetables in the amounts and types recommended by the DGA (∼270 g/day) for 8 weeks. Participants were followed for an additional 8 weeks to assess sustained consumption. Compliance was measured weekly by resonance Raman light-scattering spectroscopy (RRS). Vegetable reinforcement was tested at weeks 0, 8, 12, and 16 using a computer choice paradigm.

RESULTS

In the VI group, RRS intensity increased from week 0 to 8 (from 22,990 to 37,220), returning to baseline by week 16 (27,300). No change was observed in the AC group. There was no main effect of treatment (P = 0.974) or time (P = 0.14) and no treatment x time interaction (P = 0.44) on vegetable reinforcement. There was no moderating effect of sex (P = 0.07), age (P = 0.60), BMI (P = 0.46), delay discounting (P = 0.24), 6-n-propylthiouracil taster status (P = 0.15), or dietary disinhibition (P = 0.82) on the change in vegetable reinforcement.

CONCLUSIONS

These findings suggest no effects of the provision of a variety of vegetables to meet DGA recommendations for 8 weeks on vegetable reinforcement and highlight the difficulty in increasing vegetable consumption in adults. This trial was registered at clinicaltrials.gov as NCT02585102.

Comparing the reinforcing value of high intensity interval training versus moderate intensity aerobic exercise in sedentary adults

Exercise is a reinforcer for both animals and humans, as they will work progressively harder to gain access for the opportunity to exercise. Exercise activates brain reward pathways similar to drugs of abuse, and the magnitude of the reinforcing value of exercise is a predictor of exercise behavior. The majority of research on exercise reinforcement has studied moderate intensity aerobic exercise (MIAE) or resistance training. There is limited research on the relative reinforcing value (RRV) of high intensity interval training (HIIT), which is often reported to be a preferred form of exercise in comparison to MIAE. Experiment 1 was a pilot study of 20 sedentary females designed to compare the reliability of differences in RRV_HIIT vs RRV_MIAE over two sessions, assess protocols comparing different volumes of HIIT in comparison to MIAE, and estimate sample sizes needed for a fully powered study to assess which type of exercise protocol was a better substitute for a highly liked sedentary activity. Experiment 2 studied 44 participants to assess whether HIIT or MIAE would be better substitutes for highly liked sedentary activities. Experiment 1 showed that measures of RRV_HIIT or RRV_MIAE were reliable, and that volume of HIIT did not influence RRV_HIIT, even if it was of equal amount or duration to MIAE. Experiment 2 showed that HIIT was a more preferred substitute for sedentary behaviors than MIAE. Predictors of RRV_MIAE were liking of MIAE and pleasantness of affect post MIAE. These results suggest inactive people may find interval training to be more reinforcing than MIAE, and may be more likely to adopt and maintain an exercise program involving HIIT rather than MIAE. The next stage of research should be to understand how to sensitize the RRV of exercise to motivate sedentary people to be more active.

Bi-Directional Associations Between Real-Time Affect and Physical Activity in Weight-Discordant Siblings

Pediatric obesity confers increased risk for a host of negative psychological and physical health consequences and is reliably linked to low levels of physical activity. Affective antecedents and consequences of physical activity are thought to be important for the development and maintenance of such behavior, though research examining these associations in youth across the weight spectrum remains limited.

OBJECTIVE

This study examined bi-directional associations between affect and physical activity (i.e., moderate-to-vigorous physical activity [MVPA] and total activity counts), and the extent to which weight (body mass index z-score [z-BMI]) moderated these associations.

METHODS

Participants were drawn from a prior study of siblings (N = 77; mean age = 15.4 ± 1.4 years) discordant for weight status (39 nonoverweight siblings, 38 siblings with overweight/obesity) who completed ecological momentary assessment (EMA) with accelerometer-assessed physical activity.

RESULTS

Generalized linear mixed models indicated z-BMI moderated trait-level and momentary associations. When adolescents with higher z-BMI reported momentary negative affect, they evidenced less MVPA within the next hour. Across the sample, greater overall activity was associated with lower negative affect. However, at the momentary level, when adolescents with higher (but not lower) z-BMI evidenced greater activity, they reported decreases in negative affect.

CONCLUSIONS

Findings indicate affective experiences surrounding physical activity differ according to z-BMI. Specifically, momentary negative affect may impede momentary MVPA among youth with higher z-BMI. Further research is warranted to elucidate factors influencing these momentary associations and the extent to which these momentary associations prospectively predict weight change.

Temporal Trends in the Standing Broad Jump Performance of United States Children and Adolescents

Purpose: To estimate temporal trends in broad jump performance for United States youth, a marker of muscular fitness and health. Method: Electronic databases, topical systematic reviews, and personal libraries were systematically searched for studies reporting descriptive standing broad jump data for apparently healthy United States youth (age 10-17 years). Temporal trends at the sex-age level were estimated using sample-weighted regression models associating the year of testing to mean jump performance, with national trends standardized to the year 1985 using a post-stratified population-weighting procedure. Results: Collectively, there was a small increase of 12.6 cm (95%CI: 12.5 to 12.7) or 7.9% (95%CI: 7.1 to 8.6) in 65,527 United States youth between 1911 and 1990. Increases were greater for girls (change in means [95% CI]: 17.1 cm [16.9 to 17.3]; 11.4% [10.7 to 12.2]) compared to boys (change in means [95% CI]: 8.5 cm [8.3 to 8.7]; 4.6% [3.8 to 5.4]), but did not differ between children (10-12 years) and adolescents (13-17 years). Increases in broad jump performance were not always uniform across time, with steady and progressive increases observed for boys and children, respectively, and a diminishing rate of increase observed for girls and adolescents. Conclusions: Muscular fitness is a good marker of health, so greater broad jump performance from 1911 to 1990 may reflect corresponding changes in health. Routine assessment of broad jump performance may be useful to monitor trends in health and muscular fitness of United States youth due to its practicality, scalability, and predictive utility.

Associations between objective physical activity and emotional eating among adiposity-discordant siblings using ecological momentary assessment and accelerometers

BACKGROUND

Emotional eating is associated with obesity, though less is known regarding factors that predict emotional eating episodes in children and adolescents.

OBJECTIVES

To investigate whether moderate to vigorous physical activity (MVPA) or total activity counts 60 minutes prior to psychological stress predicted stress-related eating and positive emotional eating (ie, eating while happy), and whether adiposity (z-BMI) moderated these associations.

METHODS

Participants were drawn from a prior study of siblings (N = 77; mean age = 15.4 ± 1.4 years) discordant for weight status (39 non-overweight siblings, 38 siblings with overweight/obesity) who completed an ecological momentary assessment protocol with accelerometer-based assessment of physical activity.

RESULTS

Greater MVPA was associated with lower stress-related eating across the sample. Lower total activity (between-person effects) and lower MVPA (within-person effects) were associated with greater stress-related eating for siblings with greater z-BMI. Greater total activity was associated with lower positive emotional eating for siblings with lower z-BMI (between- and within-person).

CONCLUSIONS

Findings demonstrate potential regulating effects of prior physical activity on emotional eating at the individual and momentary level, though there are nuances depending on z-BMI. Future work is needed to examine underlying mechanisms and timescale of effects, and particularly the extent to which enhancing MVPA time among youth with z-BMI may mitigate momentary risk of stress-related eating episodes.

Weight discordant siblings' ability to reduce energy intake at a meal as compensation for prior energy intake from sugar-sweetened beverages (SSBs)

BACKGROUND

Insufficient compensation for energy from sugar-sweetened beverages (SSBs) consumed prior to meals may promote greater overall energy intake. If so, ability to compensate for prior energy intake may account for difference in adiposity between adolescents with and without overweight. Studies of fraternal siblings discordant for weight status control for some genetic and shared within-family factors, which allows for testing how putative non-shared factors, such as parental control of feeding, predicts sibling weight differences.

AIM

To determine whether same-sex weight-discordant (one with, one without overweight) adolescent siblings differ in ability to compensate for prior energy intake.

METHODS

Same-sex biological sibling pairs (mean age = 15.4; 95% confidence interval (CI) 15.1, 15.7) (n = 38 pairs; 21 male pairs) consumed a sugar-sweetened (450 kcal) or a non-nutritive-sweetened (10 kcal) liquid preload of equal volumes on separate days, followed by an ad libitum lunch. Multilevel models examined ability to compensate, dietary restraint, and parental control of child's feeding.

RESULTS

Siblings showed insufficient compensation and overate (with overweight = 44 kcal; without overweight = 32 kcal). Siblings shared little within-family similarity in compensation (intra-class correlation coefficient (ICC) = 0.20). Compensation was predicted by parental restriction and general restriction (p = 0.02) Differences in siblings' BMI z-scores were associated with differences in dietary restraint (p = 0.04) not with differences in compensation.

CONCLUSION

Sibling differences in compensation for energy from sweetened beverages were not associated with differences in their adiposity. Compensation may be determined by a constellation of factors, including age, parental feeding practices, and food characteristics.

Identification of Barriers to Adherence to a Weight Loss Diet in Women Using the Nominal Group Technique

Background: At any given time, a majority of women are engaged in some type of weight loss diet; however, these efforts are difficult to sustain for long-term weight control. Because women are more likely to develop obesity and suffer a greater severity of obesity-related health and economic consequences, we sought to identify the key factors that make adhering to a weight loss diet difficult for overweight/obese women. Methods: Ten nominal group technique (NGT) sessions aimed at identifying perceived barriers to adherence to a weight loss diet were conducted as part of a weight loss study for overweight/obese women (n = 33) during the controlled feeding weight loss phase. Results: Individual-level barriers to emerge from the sessions included knowing when to stop eating, being able to control cravings and emotional eating, and sustaining healthier dietary habits. Environmental-level barriers included family/social events that bring people together, especially those centered around food and drink, eating out, cost, and busy schedules. Conclusions: These findings offer a deeper understanding of barriers women find most salient to adhering to a weight loss diet, providing direction for the clinical application of weight loss programs.

23 Current progress in the Agricultural Research Service Beef Grand Challenge: A large-scale genetics by environment by management evaluation project

The Agricultural Research Service (ARS) Beef Grand Challenge is a cooperative, multidisciplinary effort evaluating differences in performance of genetic lines across production environments representative of different geographical regions. Weaned spring-born calves (n = 120 per location), representing natural service matings to Angus, Hereford, Simmental, Charolais, or indicus-composite (Beefmaster or Brangus) bulls from the U.S. Meat Animal Research Center Germplasm Evaluation program in south central Nebraska, are sent to wheat pasture (central Oklahoma) and winter range (eastern Montana), and weaned fall-born calves (n=40 per location) are sent to summer grazing on shortgrass prairie (northeastern Colorado) and southern mixed-grass rangeland (western Oklahoma). All cattle are fed a finishing ration representative of the region that approximately matches energy content across locations. Each calving season has a matching counterpart of calves that remain in Nebraska on a calf-fed drylot program (receiving ration followed by longer finishing ration). Breeds and sires are represented equally, to the extent possible, at each location. To detect differences in breed effects at each location and average over yearly variation, the study is being replicated for 4 years. Weights, stress measures, carcass composition (marbling, yield grade, quality grade, etc.), steak tenderness and steak fatty acid composition are collected from each location. Additionally, rumen metagenomic composition, metagenomic samples, preharvest food safety samples, and feed intake measures are collected at some locations. Grazing impacts and supplemental range feeding are also being evaluated. One year of sampling has been completed, with numeric differences observed for marbling and tenderness as well as growth performance among locations. Statistical differences will be evaluated when replicate years are collected. The USDA is an equal opportunity provider and employer.

Nutrients and Immunometabolism: Role of Macrophage NLRP3

Inflammation is largely mediated by immune cells responding to invading pathogens, whereas metabolism is oriented toward producing usable energy for vital cell functions. Immunometabolic alterations are considered key determinants of chronic inflammation, which leads to the development of chronic diseases. Studies have demonstrated that macrophages and the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome are activated in key metabolic tissues to contribute to increased risk for type 2 diabetes mellitus, Alzheimer disease, and liver diseases. Thus, understanding the tissue-/cell-type-specific regulation of the NLRP3 inflammasome is crucial for developing intervention strategies. Currently, most of the nutrients and bioactive compounds tested to determine their inflammation-reducing effects are limited to animal models. Future studies need to address how dietary compounds regulate immune and metabolic cell reprograming in humans.

Paternal high-fat diet and exercise regulate sperm miRNA and histone methylation to modify placental inflammation, nutrient transporter mRNA expression and fetal weight in a sex-dependent manner

We previously have shown that male offspring (F1) of fathers (F0) fed a high-fat (HF) diet and that exercised had greater skeletal muscle insulin signaling and reduced type 2 diabetes mellitus (T2DM) risk compared to fathers fed HF diet and that remained sedentary. The current study extends this work by hypothesizing that F0 HF diet and exercise regulate F1 T2DM risk by alterations in placental tissue growth via changes in sperm miRNA expression. To test these hypotheses, 3-week-old male C57BL/6 mice were fed a normal-fat diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months. Results showed that F0 sperm miRNA 193b expression was decreased while miRNA 204 was increased by paternal exercise. Protein expression of dimethylated histone 3 lysine 9 was decreased with F0 HF diet. Placental and fetal tissue weights were decreased by F0 HF diet in F1 males. Placental interleukin-1β and tumor necrosis factor (TNF)-α mRNA expression was reduced by paternal exercise, while nutrient transporter mRNA expression was decreased by paternal HF diet only in the placentae of F1 females. Treatment of primary placental cell with miRNA 193b inhibited TNF-α mRNA expression, and treatment of TNF-α decreased SLC38a2 mRNA expression. Moreover, paternal exercise increased body weight at weaning in a female offspring. These results demonstrate that placental tissue weight, placental nutrient transporter gene expression and fetal weights are altered by paternal exercise, while placental inflammatory gene expression is influenced by paternal exercise in offspring in a sex-specific manner.

Prenatal traumatic stress and offspring hair cortisol concentration: A nine year follow up to the Red River flood pregnancy study

INTRODUCTION

Findings concerning the relationship between maternal prenatal and child cortisol concentrations are inconsistent. This study examined whether the influence of an objective traumatic stressor during pregnancy, distance from a natural flood disaster, moderated the association between prenatal maternal diurnal cortisol and 9-year old offspring hair cortisol concentrations.

METHODS

Data were collected from 56 of the mothers who took part in a study of flood-related pregnancy outcomes in 2009 and their children. Data included distance of the maternal home from evacuation areas, four maternal saliva cortisol assessments (waking, 30 min after waking, afternoon, and before bed) provided within 3-months of the flood crest and child hair samples to assess cortisol secretion over the past month.

RESULTS

There was a significant interaction between proximity to flooding during pregnancy and maternal cortisol AUC predicting child hair cortisol, after controlling for maternal age, gestational age at cortisol sampling, sex of the child, current socioeconomic status and current maternal stress. At greater distance from flooding (lower stress conditions) there was a non-statistically significant positive association between maternal cortisol and child cortisol. In contrast, living closer to flooding (higher stress conditions) produced a significant negative association between maternal and child cortisol.

CONCLUSION

Experiencing a traumatic stressor during pregnancy may alter maternal-fetal programming of the hypothalamic-pituitary-adrenal axis. The direct threat of flooding led to offspring cortisol concentrations that resembled cortisol production seen in mothers with symptoms of PTSD and their offspring. This alteration is evident in nine-year-old offspring and may help explain inconsistencies in the previous literature.

Increasing the Reinforcing Value of Exercise in Overweight Adults

Objectives: This study determined whether a moderate- or high-dose exercise program increases exercise reinforcement. Increasing the relative reinforcing value of exercise (RRV_exercise; i.e., incentive sensitization of exercise) may increase the usual physical activity (PA) participation. Preference and/or tolerance for the intensity of exercise was also assessed.

Design: Sedentary men and women (body mass index, BMI: 25–35 kg/m²) were randomized into parallel exercise training groups expending either 300 (n = 18) or 600 (n = 18) kcal/exercise session, five sessions/week, for 12 weeks.

Methods: The RRV_exercise was determined by how much work was performed for exercise relative to a sedentary alternative in a progressive ratio schedule task. Preference and tolerance for exercise intensity were determined by questionnaire.

Results: RRV_exercise increased (P < 0.05) in both groups. Exercise reinforcement, defined as the amount of work completed for exercise without taking sedentary activity into account, increased (P < 0.01) in the 600 kcal group only. Preference and tolerance for exercise intensity increased (P < 0.01) in both groups, which predicted increases in RRV_exercise.

Conclusion: Expending 300 or 600 kcal, 5 days/week increases RRV_exercise, while 600 kcal, 5 days/week may be needed to increase exercise reinforcement.

Active Videogames to Promote Traditional Active Play: Increasing the Reinforcing Value of Active Play Among Low-Active Children

Background: Exercise reinforcement predicts physical activity of children. Repeated exposures of physical activity may increase physical activity reinforcement (incentive sensitization). Active videogame (AVG) play produces light-to-moderate-intensity physical activity. Ideally, AVG play would transition to nonscreen-based active play through incentive sensitization of traditional active play (TAP), providing AVG does not increase sedentary videogame (SVG) reinforcement. Greater autonomy increases motivation toward traditional physical activity, but whether autonomy enhances incentive sensitization has not been studied. Objectives: To determine whether autonomy over AVG play promotes incentive sensitization of TAP or SVG. Methods: Inactive children (ages 8-12; 5th-97th body mass index percentile) were provided with AVG and SVG for 6 weeks and assigned to either a high autonomy (n = 25) or low autonomy (n = 24) group, differentiated by AVG choice and more freedom over amount of play. Both groups played AVG 3 days per week. SVG were played ad libitum. Participants completed an operant responding task to measure the relative reinforcing value (RRV) of AVG versus SVG (RRVAVG vs. SVG) and AVG versus TAP (RRVAVG vs. TAP) at baseline, 6 weeks, and 10 weeks. Results: RRVAVG vs. SVG increased over time (P = 0.056) but did not differ by autonomy or autonomy × time (P = 0.184). RRVAVG vs. TAP decreased over time (P = 0.033) but did not differ by autonomy or autonomy × time (P = 0.73). Conclusion: AVG play does not increase motivation toward SVG and increases motivation to play AVG relative to TAP. Providing higher autonomy did not promote incentive sensitization of play.

Food Price Elasticity by Status of Participation in Federal Food Assistance Programs: A Laboratory-Based Grocery Store Study

Background

Federal food assistance programs target low-income and nutritionally vulnerable Americans, with the dual goals of reducing food insecurity and improving diet quality. Individuals on limited food budgets may face constraints on their ability to purchase healthy foods when their prices increase, which could mitigate the intended impact of federal feeding programs. To better understand the effect of food price changes on healthy food purchases, we focus on eggs, which are rich in many important nutrients and can be a healthy part of a wide range of cultural food menus.

Objective

We use a laboratory-based grocery store experiment (n = 80) to examine the difference in price elasticity of eggs between individuals participating in food assistance programs and those not participating in these programs. This trial was registered at clinicaltrials.gov as NCT03296878.

Methods

Subjects completed several food purchasing trials, as well as questionnaires that assessed demographic, psychosocial, and other factors. Mixed linear regression models were used to assess the relationship between food price changes and food purchases (price elasticity).

Results

No difference in price elasticity was observed between groups, but subjects in both groups decreased their egg purchases by 6.9–8.6% for every 10% increase in egg price. For every 10% increase in the price of all nonegg foods, egg purchases increased by 3.3% among federal food assistance program participants but not nonparticipants, and purchases for foods such as lean meats, low-fat dairy, fruits, vegetables, and whole grains decreased by up to 14% among both groups.

Conclusions

Efforts to emphasize healthy eating strategies for individuals on limited budgets will be especially important during times of food price increases. Additional research is needed to estimate the price elasticities of other food groups among individuals participating in federal food assistance programs.

Genetic variations in the dopamine reward system influence exercise reinforcement and tolerance for exercise intensity

BACKGROUND

Exercise is a reinforcing behavior and finding exercise highly reinforcing is characteristic of habitual exercisers. Genotypes related to dopamine metabolism moderate the reinforcing value of behaviors, but genetic moderators of exercise reinforcement have not been established.

PURPOSE

Determine whether singular nucleotide polymorphisms (SNPs) that moderate central reward pathways and pain neurotransmission are associated with exercise reinforcement, tolerance for exercise intensity, and usual physical activity.

METHODS

Adults (n = 178) were measured for the reinforcing value of exercise relative to sedentary activities (RRV_exercise), minutes of moderate-to-vigorous physical activity (MVPA) and completed the Preference for and Tolerance of the Intensity of Exercise Questionnaire. Genotyping of 23 SNPs known to influence central dopamine tone, pain, or physical activity was performed. ANOVA tested differences in RRV_exercise, tolerance, and MVPA among genotype groups. Linear regression controlling for BMI, sex, and liking of exercise was used to further predict the association of genotype on RRV_exercise, tolerance, and MVPA.

RESULTS

Having at least one copy of the G allele for the DRD2/ANKK1 polymorphism (rs1800497) conferred greater RRV_exercise. Greater tolerance for exercise intensity was observed among those homozygous for the T allele for the CNR1 polymorphism (rs6454672), had at least one copy of the G allele for the GABRG3 polymorphism (rs8036270), or had at least one copy of the T allele for the LPR polymorphism (rs12405556). Homozygous individuals for the T allele at rs6454672 exhibited greater MVPA.

CONCLUSION

Similar to other reinforcing behaviors, there is a genetic contribution to exercise reinforcement, tolerance for exercise intensity, and MVPA.

Ca2+ entry via TRPC1 is essential for cellular differentiation and modulates secretion via the SNARE complex

Properties of adipocytes, including differentiation and adipokine secretion, are crucial factors in obesity-associated metabolic syndrome. Here, we provide evidence that Ca²⁺ influx in primary adipocytes, especially upon Ca²⁺ store depletion, plays an important role in adipocyte differentiation, functionality and subsequently metabolic regulation. The endogenous Ca²⁺ entry channel in both subcutaneous and visceral adipocytes was found to be dependent on TRPC1–STIM1, and blocking Ca²⁺ entry with SKF96365 or using TRPC1^−/− knockdown adipocytes inhibited adipocyte differentiation. Additionally, TRPC1^−/− mice have decreased organ weight, but increased adipose deposition and reduced serum adiponectin and leptin concentrations, without affecting total adipokine expression. Mechanistically, TRPC1-mediated Ca²⁺ entry regulated SNARE complex formation, and agonist-mediated secretion of adipokine-loaded vesicles was inhibited in TRPC1^−/− adipose. These results suggest an unequivocal role of TRPC1 in adipocyte differentiation and adiponectin secretion, and that loss of TRPC1 disturbs metabolic homeostasis.

This article has an associated First Person interview with the first author of the paper.

Summary: TRPC1 modulates Ca²⁺ entry, which is essential in adipocyte differentiation and adiponectin secretion, through facilitating SNARE complex formation, thereby maintaining metabolic homeostasis.

Eating Responses to External Food Cues in Weight Discordant Siblings

PURPOSE

Heightened responsivity to external food cues may promote energy intake and account for differences in weight status between nonoverweight and overweight adolescents. Studies of weight-discordant fraternal siblings control for some genetic and shared within-family factors, which allow for testing of other nonshared factors relevant to sibling weight differences.The aim of the study was to determine whether same-sex weight-discordant (one nonoverweight and one overweight) adolescent siblings differ in responsiveness to external food cues.

METHODS

Weight-discordant siblings' (n = 38 pairs) energy consumption was compared following both an appetizing food (pizza) on one day and a control activity (reading) on another day. Multilevel models examined intrafamily similarity, and regressions examined associations with adiposity.

RESULTS

Siblings shared little similarity in cue responsivity (ρ = .10). However, sibling body mass index z-scores difference was not associated with differences in cue responsivity. Moreover, when tested as groups, nonoverweight and overweight siblings did not differ for cue responsivity (p > .84).

CONCLUSION

Weight-discordant adolescent siblings show little similarity in responses to food cues. Differences in sibling weight status were not predicted by differences in responses to food cues. Thus, nonshared factors other than cue responsivity must contribute to weight differences of adolescent siblings.

Study design for a clinical trial to examine food price elasticity among participants in federal food assistance programs: A laboratory-based grocery store study

We present a protocol for a study investigating the effect of food price changes on purchasing decisions among individuals participating in federal food assistance programs and among those not participating in these programs. We use a laboratory-based grocery store design, which provides greater control over factors influencing food purchasing than in situ experiments in actual grocery stores. We focus primarily, but not exclusively, on eggs because they are highly nutritious, easy to prepare, can be included in many different dishes, and are a part of a wide range of cultural food menus. The primary aim of this study is to compare the own-and cross-price elasticity of eggs between individuals participating in federal food assistance programs and those not participating in these programs. Our secondary aims are to 1) compare the own- and cross-price elasticity of eggs between overweight/obese individuals and non-overweight/obese individuals, 2) examine whether delay discounting moderates the effect of income on own- and cross-price elasticity, 3) examine whether subjective social status moderates the effect of participation in federal food assistance programs on the purchase of high nutrient-dense foods, and 4) examine whether usual psychological stress level moderates the effect of subjective social status on the purchase of high-nutrient dense foods. The results of this study will provide information about the drivers of food demand among low-income adults. A better understanding of these drivers is needed to develop effective nutrition interventions for this large population.

Energy compensation in response to aerobic exercise training in overweight adults

Weight loss from exercise is often less than expected. Putative compensatory mechanisms may limit exercise-induced reductions in body fat and might be proportional to exercise energy expenditure (ExEE). This study was conducted to determine compensation for (the difference between accumulated exercise energy expenditure and changes in body tissue energy stores) and compensatory responses to 1,500 or 3,000 kcal/wk of ExEE. Overweight-to-obese ( n = 36) sedentary men and women were randomized to groups expending 300 or 600 kcal/exercise session, 5 days/wk, for 12 wk. Fourteen participants in the 300-kcal group and 15 in the 600-kcal group completed the study. The primary outcome was energy compensation assessed through changes in body tissue energy stores. Secondary outcomes were putative compensatory responses of resting metabolic rate, food reinforcement, dietary intake, and serum acylated ghrelin and glucagon-like peptide-1. All measures were determined pre- and posttraining. The 3,000 kcal/wk group decreased ( P < 0.01) percentage and kilograms of body fat, while the 1,500 kcal/wk group did not. The 1,500 and 3,000 kcal/wk groups compensated for 943 (-164 to 2,050) and 1,007 (32 to 1,982) kcal/wk (mean, 95% CI, P ≥ 0.93), or 62.9% and 33.6% of ExEE, respectively. Resting metabolic rate and energy intake did not change. Food reinforcement and glucagon-like peptide-1 decreased ( P < 0.02), whereas acylated ghrelin increased ( P ≤ 0.02). Compensation is not proportional to ExEE. Similar energy compensation occurred in response to1,500 and 3,000 kcal/wk of ExEE. ExEE of 3,000 kcal/wk is sufficient to exceed compensatory responses and reduce fat mass.

Nutrient intake disparities in the US: modeling the effect of food substitutions

Background

Diet quality among federal food assistance program participants remains low, and little research has assessed the diet quality of food insecure non-participants. Further research is needed to assess the extent to which food substitutions can improve the nutritional status of these vulnerable populations. Substituting egg dishes for other commonly consumed dishes at certain eating occasions may be an effective strategy for improving the daily nutrient intake among these groups. Eggs are rich in many important nutrients, and are low-cost and part of a wide range of cultural food menus, which are important considerations for low-income and ethnically diverse populations. To help guide the focus of targeted nutrition interventions and education campaigns for vulnerable populations, the present work begins by 1) estimating the prevalence of nutrient inadequacy among these groups, and then models the effect of consuming egg dishes instead of commonly consumed dishes at each eating occasion on 2) the prevalence of nutrient inadequacy, and 3) the mean intake of nutrients.

Methods

Dietary data from 34,741 adults ≥ 20 y were acquired from the National Health and Nutrition Examination Survey, 2001–2014. Diet pattern modeling was used to substitute commonly consumed egg dishes for commonly consumed main dishes at breakfast, lunch, and dinner. National Cancer Institute usual intake methods were used to estimate the prevalence of inadequate intake of 31 nutrients pre- and post-substitution, and a novel index was used to estimate change in intake of all nutrients collectively.

Results

Substituting eggs for commonly consumed main dishes at lunch or dinner did not change total daily nutrient intake for each group (P > 0.05), but decreased the prevalence of vitamin D inadequacy by 1–4 percentage points (P < 0.01). Substituting eggs for commonly consumed foods at breakfast increased the prevalence of folate inadequacy by 8–12 percentage points among each group (P < 0.01).

Conclusions

When making food substitutions to increase nutrient intake, eating occasion should be an important consideration. Further research is needed to better understand how food substitutions affect diet costs, which may be an important driver of food purchasing decisions among low income individuals with limited food budgets.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0360-z) contains supplementary material, which is available to authorized users.

Paternal exercise protects mouse offspring from high-fat-diet-induced type 2 diabetes risk by increasing skeletal muscle insulin signaling

Paternal obesity increases, while paternal exercise decreases, offspring obesity and type 2 diabetes (T2D) risk; however, no studies have determined whether a paternal high-fat (HF) diet and exercise interact to alter offspring body weight (BW), adiposity and T2D risk. Three-week-old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF-diet-fed dams. After weaning, male offspring were fed an NF or HF diet for an additional 3 months. F1 male mice whose fathers ate an HF diet had decreased % body fat accompanied by decreased gene expression of beige adipocyte marker FGF21. However, paternal HF-diet-induced reductions in F1 offspring % body fat normalized but did not reduce T2D risk. Exercise was protective against paternal HF-diet-induced insulin resistance by increasing the expression of insulin signaling (GLUT4, IRS1 and PI3K) markers in skeletal muscle resulting in normal T2D risk. When fathers were fed an HF diet and exercised, a postnatal HF diet increased beiging (PPARγ). Thus, these findings show that increases in T2D risk in male offspring when the father consumes an HF diet can be normalized when the father also exercises preconception and that this protection may occur by increases in insulin signaling potential within offspring skeletal muscle. Future studies should further determine the physiological mechanism(s) underlying the beneficial effects of exercise through the paternal lineage.

The TRPC1 Ca2+-permeable channel inhibits exercise-induced protection against high-fat diet-induced obesity and type II diabetes

The transient receptor potential canonical channel-1 (TRPC1) is a Ca²⁺-permeable channel found in key metabolic organs and tissues, including the hypothalamus, adipose tissue, and skeletal muscle. Loss of TRPC1 may alter the regulation of cellular energy metabolism resulting in insulin resistance thereby leading to diabetes. Exercise reduces insulin resistance, but it is not known whether TRPC1 is involved in exercise-induced insulin sensitivity. The role of TRPC1 in adiposity and obesity-associated metabolic diseases has not yet been determined. Our results show that TRPC1 functions as a major Ca²⁺ entry channel in adipocytes. We have also shown that fat mass and fasting glucose concentrations were lower in TRPC1 KO mice that were fed a high-fat (HF) (45% fat) diet and exercised as compared with WT mice fed a HF diet and exercised. Adipocyte numbers were decreased in both subcutaneous and visceral adipose tissue of TRPC1 KO mice fed a HF diet and exercised. Finally, autophagy markers were decreased and apoptosis markers increased in TRPC1 KO mice fed a HF diet and exercised. Overall, these findings suggest that TRPC1 plays an important role in the regulation of adiposity via autophagy and apoptosis and that TRPC1 inhibits the positive effect of exercise on type II diabetes risk under a HF diet-induced obesity environment.

Cost-effectiveness of Family-Based Obesity Treatment

BACKGROUND AND OBJECTIVES

We translated family-based behavioral treatment (FBT) to treat children with overweight and obesity and their parents in the patient-centered medical home. We reported greater reductions in child and parent weight at 6 and 24 months compared with an attention-controlled information control (IC) group. This article reports the cost-effectiveness of long-term weight change for FBT compared with IC.

METHODS

Ninety-six children 2 to 5 years of age with overweight or obesity and with parents who had a BMI ≥25 were randomly assigned to FBT or IC, and both received diet and activity education (12-month treatment and 12-month follow-up). Weight loss and cost-effectiveness were assessed at 24 months. Intention-to-treat, completers, and sensitivity analyses were performed.

RESULTS

The average societal cost per family was $1629 for the FBT and $886 for the IC groups at 24 months. At 24 months, child percent over BMI (%OBMI) change decreased by 2.0 U in the FBT group versus an increase of 4.4 U in the IC group. Parents lost 6.0 vs 0.2 kg at 24 months in the FBT and IC groups, respectively. The incremental cost-effectiveness ratios (ICERs) for children and parents' %OBMI were $116.1 and $83.5 per U of %OBMI, respectively. Parental ICERs were also calculated for body weight and BMI and were $128.1 per 1, and $353.8/ per kilogram, respectively. ICER values for child %OBMI were similar in the intention-to-treat group ($116.1/1 U decrease) compared with completers ($114.3).

CONCLUSIONS

For families consisting of children and parents with overweight, FBT presents a more cost-effective alternative than an IC group.

Postprandial energy metabolism and substrate oxidation in response to the inclusion of a sugar- or non-nutritive sweetened beverage with meals differing in protein content

Background

The macronutrient composition of the diet may play a more important role in maintaining a healthy body weight and preventing obesity than previously thought. The primary goal of this research was to determine the extent to which the simple addition of a small serving of a sugar-sweetened beverage (SSB) to meals with different macronutrient compositions impacts appetite, energy metabolism and substrate oxidation.

Methods

Appetite, energy metabolism and substrate oxidation were measured in 27 healthy weight adults (age = 23 ± 5 y; BMI = 23 ± 2 kg/m²) on two occasions in a room calorimeter after consuming a SSB or a non-nutritive-sweetened beverage (NNSB) with a standard (15%E) or high- (30%E) protein meal. Meal carbohydrate (CHO) content was adjusted to maintain equivalent calories for both study visits. All meals were composed of the same foods and provided 17 g of fat and 500 non-beverage calories. Study visits were separated by at least 1 week and menstruating females were studied during the luteal phase (Days 15-20). The effects of sex, protein level and beverage type and their interactions on satiety, appetite for foods with specific taste profiles, diet-induced thermogenesis (DIT) and rates of substrate oxidation were assessed using a 3-way Repeated Measures Analysis of Variance.

Results

Increasing dietary protein decreased hunger and increased satiety. Males were hungrier and less satisfied with the meals than females. Increasing dietary protein also decreased the desire to eat something savory, salty and fatty and the males had a greater appetite for food with these taste profiles. Interestingly, there was no effect of sex, dietary protein or beverage type on the desire to eat something sweet. The inclusion of a SSB markedly suppressed DIT (2.42% ± 5.91%) and fat oxidation (9.87 ± 11.09 g).

Conclusion

Appetite sensations, food preferences, energy expenditure and substrate oxidation are significantly altered in response to changes in meal macronutrient composition produced by modifications in the protein content of a meal and consumption of a SSB. Most notably, consumption of a SSB during a meal markedly reduces energy efficiency and fat oxidation independent of macronutrient composition.

Trial registrations

ClinicalTrials.gov: NCT02211599, registered August 05, 2014.

Effects of prenatal low protein and postnatal high fat diets on visceral adipose tissue macrophage phenotypes and IL-6 expression in Sprague Dawley rat offspring

Adipose tissue macrophages (ATM) are implicated in adipose tissue inflammation and obesity-related insulin resistance. Maternal low protein models result in fetal programming of obesity. The study aims to answer whether maternal undernutrition by protein restriction affects the ATM M1 or M2 phenotype under postnatal high fat diet in F1 offspring. Using a rat model of prenatal low protein (LP, 8% protein) diet followed by a postnatal high fat energy diet (HE, 45% fat) or low fat normal energy diet (NE, 10% fat) for 12 weeks, we investigated the effects of these diets on adiposity, programming of the offspring ATM phenotype, and the associated inflammatory response in adipose tissue. Fat mass in newborn and 12-week old LP fed offspring was lower than that of normal protein (20%; NP) fed offspring; however, the adipose tissue growth rate was higher compared to the NP fed offspring. While LP did not affect the number of CD68⁺ or CD206⁺ cells in adipose tissue of NE offspring, it attenuated the number of these cells in offspring fed HE. In offspring fed HE, LP offspring had a lower percentage of CD11c⁺CD206⁺ ATMs, whose abundancy was correlated with the size of the adipocytes. Noteworthy, similar to HE treatment, LP increased gene expression of IL-6 within ATMs. Two-way ANOVA showed an interaction of prenatal LP and postnatal HE on IL-6 and IL-1β transcription. Overall, both LP and HE diets impact ATM phenotype by affecting the ratio of CD11c⁺CD206⁺ ATMs and the expression of IL-6.

Effect of Interpersonal and Cognitive Stressors on Habituation and the Utility of Heart Rate Variability to Measure Habituation

Habituation is a decrease in responding to a repeated stimulus. Operant responding and salivation measure habituation in eating behaviour research. Stress may increase eating by acting as a distractor, yielding spontaneous recovery and prolonging responding for food. Our research tested differences in the ability of cognitive and interpersonal stressors to recover responding for food. We also tested heart rate variability (HRV) as a measure of habituation. Twenty women worked for portions of macaroni and cheese for 15 trials on three separate laboratory visits. Between the 12th and 13th trial, one of three different stressor types (speech, stroop and subtraction) was presented during each visit. HRV was measured continuously throughout the laboratory visits. Responding for food declined across the 12 trials with no difference in rate of habituation by visit (p > 0.8) There was no difference between stressor type in the magnitude of spontaneous recovery after each stressor (p > 0.8). Rates of habituation of HRV variables correlated (p < 0.02) with the rate of operant responding habituation. Cognitive and interpersonal stressors do not differ in their ability to recover reduced responding for food. HRV variables may measure habituation to food similar to operant responding. Copyright © 2014 John Wiley & Sons, Ltd.