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The COVID-19 pandemic has changed routines and habits, raising stress and anxiety levels of individuals worldwide. The goal of this qualitative study was to advance the understanding of how pandemic-related changes affected sleep, diet, physical activity (PA), and stress among adults. We conducted semi-structured, qualitative interviews with 185 participants and selected 33 interviews from a represented sample based on age, race, and gender for coding and analysis of themes. After coding for thematic analysis, results demonstrated four primary themes: sleep, diet, PA, and stress. Sleep sub-themes such as poorer sleep quality were reported by 36% of our participants, and 12% reported increased an frequency of vivid dreams and nightmares. PA was decreased in 52% of our participants, while 33% experienced an increase and 15% experienced no change in PA. Participants also reported having an improved diet, mostly among women. Stress was elevated in 79% of our participants and was more likely to be discussed by women. Many participants reported how stress was involved in precipitating health behavior change, especially for sleep. Increased stress was also linked to elevated anxiety and depression among participants. The results of this qualitative study demonstrate how managing stress could have a beneficial effect on promoting health behaviors and mental health during the COVID-19 pandemic and beyond. [ABSTRACT FROM AUTHOR]

The use of classic nonparametric tests (cNPTs), such as the Kruskal–Wallis and Mann–Whitney U tests, in the presence of unequal variance for between-group comparisons of means and medians may lead to marked increases in the rate of falsely rejecting null hypotheses and decreases in statistical power. Yet, this practice remains prevalent in the scientific literature, including nutrition and obesity literature. Some nutrition and obesity studies use a cNPT in the presence of unequal variance (i.e. heteroscedasticity), sometimes because of the mistaken rationale that the test corrects for heteroscedasticity. Herein, we discuss misconceptions of using cNPTs in the presence of heteroscedasticity. We then discuss assumptions, purposes, and limitations of 3 common tests used to test for mean differences between multiple groups, including 2 parametric tests: Fisher's ANOVA and Welch's ANOVA; and 1 cNPT: the Kruskal–Wallis test. To document the impact of heteroscedasticity on the validity of these tests under conditions similar to those used in nutrition and obesity research, we conducted simple simulations and assessed type I error rates (i.e. false positives, defined as incorrectly rejecting the null hypothesis). We demonstrate that type I error rates for Fisher's ANOVA, which does not account for heteroscedasticity, and Kruskal–Wallis, which tests for differences in distributions rather than means, deviated from the expected significance level. Greater deviation from the expected type I error rate was observed as the heterogeneity increased, especially in the presence of an imbalanced sample size. We provide brief tutorial guidance for authors, editors, and reviewers to identify appropriate statistical tests when test assumptions are violated, with a particular focus on cNPTs. [ABSTRACT FROM AUTHOR]

Objective: Appetite responses to 3 days of overfeeding (OF) were examined as correlates of longitudinal weight change in adults classified as obesity prone (OP) or obesity resistant (OR).Methods: OP (n = 22) and OR (n = 30) adults consumed a controlled eucaloric and OF diet (140% of energy needs) for 3 days, followed by 3 days of ad libitum feeding. Hunger and satiety were evaluated by visual analog scales. Ghrelin and peptide YY (PYY) levels were measured during a 24-hour inpatient visit on day 3. Body weight and composition were measured annually for 4.0 ± 1.3 years.Results: Dietary restraint and disinhibition were greater in OP than OR (mean difference: 3.5 ± 1.2 and 3.3 ± 0.9, respectively; P < 0.01) participants, and disinhibition was associated with longitudinal weight change (n = 48; r = 0.35; P = 0.02). Compared with the eucaloric diet, energy intake fell significantly in OR participants following OF (P = 0.03) but not in OP (P = 0.33) participants. Twenty-four-hour PYY area under the curve values increased with OF in OR (P = 0.02) but not in OP (P = 0.17) participants. Furthermore, changes in PYY levels with OF correlated with measured energy intake (r = -0.36; P = 0.01).Conclusions: Baseline disinhibition and PYY responses to OF differed between OP and OR adults. Dietary disinhibition was associated with 5-year longitudinal weight gain. Differences in appetite regulation may underlie differences in propensity for weight gain. [ABSTRACT FROM AUTHOR]

Background Regression to the mean (RTM) is a statistical phenomenon where initial measurements of a variable in a nonrandom sample at the extreme ends of a distribution tend to be closer to the mean upon a second measurement. Unfortunately, failing to account for the effects of RTM can lead to incorrect conclusions on the observed mean difference between the 2 repeated measurements in a nonrandom sample that is preferentially selected for deviating from the population mean of the measured variable in a particular direction. Study designs that are susceptible to misattributing RTM as intervention effects have been prevalent in nutrition and obesity research. This field often conducts secondary analyses of existing intervention data or evaluates intervention effects in those most at risk (i.e., those with observations at the extreme ends of a distribution). Objectives To provide best practices to avoid unsubstantiated conclusions as a result of ignoring RTM in nutrition and obesity research. Methods We outlined best practices for identifying whether RTM is likely to be leading to biased inferences, using a flowchart that is available as a web-based app at https://dustyturner.shinyapps.io/DecisionTreeMeanRegression/. We also provided multiple methods to quantify the degree of RTM. Results Investigators can adjust analyses to include the RTM effect, thereby plausibly removing its biasing influence on estimating the true intervention effect. Conclusions The identification of RTM and implementation of proper statistical practices will help advance the field by improving scientific rigor and the accuracy of conclusions. This trial was registered at clinicaltrials.gov as NCT00427193. [ABSTRACT FROM AUTHOR]

Background: Objective indicators of dietary intake (e.g., biomarkers) are needed to overcome the limitations of self-reported dietary intake assessment methods in adolescents. To our knowledge, no controlled feeding studies to date have evaluated the validity of urinary sodium, nitrogen, or sugar excretion as dietary biomarkers in adolescents.Objective: This investigation aimed to evaluate the validity of urinary sodium, nitrogen, and total sugars (TS) excretion as biomarkers for sodium, protein, and added sugars (AS) intake in nonobese adolescents.Methods: In a crossover controlled feeding study design, 33 adolescents [12-18 y of age, 47 ± 25th percentile (mean ± SD) of body mass index (BMI; in kg/m2) for age] consumed 5% AS [low added sugars (LAS)] and 25% AS [high added sugars (HAS)] isocaloric, macronutrient-matched (55% carbohydrate, 30% fat, and 15% protein) diets for 7 d each, in a randomly assigned order, with a 4-wk washout period between diets. On the final 2 d of each diet period, 24-h urine samples were collected. Thirty-two adolescents completed all measurements (97% retention).Results: Urinary sodium was not different from the expected 90% recovery (mean ± SD: 88% ± 18%, P = 0.50). Urinary nitrogen was correlated with protein intake (r = 0.69, P < 0.001), although it was below the 80% expected recovery (62% ± 7%, P < 0.001). Urinary TS values were correlated with AS intake during the HAS diet (r = 0.77, P < 0.001) and had a higher R2 value of 0.28 than did AS intake (R2 = 0.36). TS excretion differed between LAS (0.226 ± 0.09 mg/d) and HAS (0.365 ± 0.16 mg/d) feeding periods (P < 0.001).Conclusions: Urinary sodium appears to be a valid biomarker for sodium intake in nonobese adolescents. Urinary nitrogen is associated with protein intake, but nitrogen excretion rates were less than previously reported for adults, possibly owing to adolescent growth rates. TS excretion reflects AS at 25% AS intake and was responsive to the change in AS intake. Thus, urinary biomarkers are promising objective indicators of dietary intake in adolescents, although larger-scale feeding trials are needed to confirm these findings. This trial was registered at clinicaltrials.gov as NCT02455388. [ABSTRACT FROM AUTHOR]

Objective: To determine whether a social cognitive theory (SCT)-based intervention improves resistance training (RT) maintenance and strength, and reduces prediabetes prevalence. Research design and methods: Sedentary, overweight/obese (BMI: 25–39.9 kg/m2) adults aged 50–69 (N = 170) with prediabetes participated in the 15-month trial. Participants completed a supervised 3-month RT (2×/wk) phase and were randomly assigned (N = 159) to one of two 6-month maintenance conditions: SCT or standard care. Participants continued RT at a self-selected facility. The final 6-month period involved no contact. Assessments occurred at baseline and months 3, 9, and 15. The SCT faded-contact intervention consisted of nine tailored transition (i.e., supervised training to training alone) and nine follow-up sessions. Standard care involved six generic follow-up sessions. Primary outcomes were prevalence of normoglycemia and muscular strength. Results: The retention rate was 76%. Four serious adverse events were reported. After 3 months of RT, 34% of participants were no longer prediabetic. This prevalence of normoglycemia was maintained through month 15 (30%), with no group difference. There was an 18% increase in the odds of being normoglycemic for each % increase in fat-free mass. Increases in muscular strength were evident at month 3 and maintained through month 15 (P<0.001), which represented improvements of 21% and 14% for chest and leg press, respectively. Results did not demonstrate a greater reduction in prediabetes prevalence in the SCT condition. Conclusions: Resistance training is an effective, maintainable strategy for reducing prediabetes prevalence and increasing muscular strength. Future research which promotes RT initiation and maintenance in clinical and community settings is warranted. Trial Registration: ClinicalTrials.gov . [ABSTRACT FROM AUTHOR]

Physique competitions are events in which competitors are judged on muscular appearance and symmetry. The purpose of this retrospective case study was to describe changes in dietary intake, body mass/composition, and the menstrual cycle during the 20-week competition preparation (PREP) and 20-week post competition recovery (REC) periods of a drug-free amateur female figure competitor (age = 26-27, BMI = 19.5 kg/m²). Dietary intake (via weighed food records) and body mass were assessed daily and averaged weekly. Body composition was estimated via Dual-energy X-ray absorptiometry (DXA) and 7-site skinfold measurements. Energy intake, body mass and composition, and energy availability decreased during the 20-week PREP period (changes of ~298 kcals, 5.1 kg, 6.5% body fat, and 5.4 kcal/kg fat free mass, respectively) and returned to baseline values by end of the 20-week REC period. Menstrual cycle irregularity was reported within the first month of PREP and the last menstruation was reported at week 11 of PREP. Given the potentially adverse health outcomes associated with caloric restriction, future, prospective cohort studies on the physiological response to PREP and REC are warranted in drug-free, female physique competitors. [ABSTRACT FROM AUTHOR]

Effectively preventing and treating chronic diseases through health behavior changes often require intensive theory- and evidence-based intervention including long-term maintenance components. We assessed the efficacy of theory-based maintenance approaches varying by dose for persistently performing resistance training (RT) with the hypothesis that a higher-dose social cognitive theory (SCT) approach would produce greater RT adherence than lower-dose Standard. The Resist-Diabetes study first established 2×/week resistance training (RT) in a 3-month supervised intervention in older (50-69 years, N = 170), overweight to obese (BMI 25-39.9 kg/m) previously inactive adults who fit prediabetes criteria (fasting glucose concentration = 95-125 mg/dl; oral glucose tolerance test 2-h glucose concentration = 140-199 mg/dl or both). After the supervised phase, participants ( N = 159) were then randomly assigned to one of two conditions for transition (3 weeks) and then RT alone in community settings for extended contact, maintenance (6 months), and then no contact (6 months). SCT featured continued tailored, interactive personal, and web-based check-ups focused on RT, self-regulation, and a barrier/strategies approach. Standard involved low-dose, generic personal, and web-based check-ups within the same theoretical approach. SCT and Standard both resulted in similar RT, 2×/week adherence during maintenance (74.4 %) and no-contact phases (53.1 %). Cost analysis indicated the Standard intervention for transition and maintenance was inexpensive ($160). Standard can be translated into practice with the potential for continuous contact and persistence in RT beyond the typical program maintenance phase. [ABSTRACT FROM AUTHOR]

The δ13C value of blood is a novel proposed biomarker of added sugars (AS) intake. AS prediction equations using either a single- (δ13C) or dual-isotope model (δ13C and δ15N) were previously developed in an adult population with high AS intake living in southwest Virginia (reference group). The purpose of this investigation was to test the δ13C single- and δ13C and δ15N dual-isotope prediction equations for AS intake in adults with a lower mean AS intake and different demographic characteristics (test group). The blood samples for the reference (n = 257 for single-isotope, n = 115 for dual-isotope) and test groups (n = 56) were analyzed for δ13C and δ15N values using natural abundance stable isotope mass spectrometry and were compared to reported dietary AS intake. When the δ13C single-isotope equation was applied to the test group, predicted AS intake was not significantly different from reported AS intake (mean difference ± standard error = −3.6 ± 5.5 g, Z = −0.55, p = 0.51). When testing the dual-isotope equation, predicted AS was different from reported AS intake (mean difference ± SEM = 13.0 ± 5.4 g, Z = −2.95, p = 0.003). δ13C value was able to predict AS intake using a blood sample within this population subset. The single-isotope prediction equation may be an alternative method to assess AS intake and is more objective, cost-feasible, and efficient than traditional dietary assessment methods. However, more research is needed to assess this biomarker with rigorous study designs such as controlled feeding. [ABSTRACT FROM AUTHOR]

The study objective was to validate a food frequency and lifestyle questionnaire (FFLQ) to assess vitamin D intake and lifestyle factors affecting status. Methods: Data collected previously during the fall (n = 86), winter (n = 49), and spring (n = 67) in collegiate-athletes (Study 1) and in active adults (n = 123) (Study 2) were utilized. Study 1: Vitamin D intake and ultraviolet B exposure were estimated using the FFLQ and compared to serum 25(OH)D concentrations via simple correlation and linear regression modeling. Study 2: Vitamin D intake from food was estimated using FFLQ and compared to vitamin D intake reported in 7-Day food diaries via paired t-test and Bland–Altman analysis. Results: Study 1: Serum 25(OH)D was not associated with vitamin D intake from food, food plus supplements, or sun exposure, but was associated with tanning bed use (r = 0.39) in spring, supplement use in fall (r = 0.28), and BMI (body mass index) (r = −0.32 to −0.47) across all seasons. Serum 25(OH)D concentrations were explained by BMI, tanning bed use, and sun exposure in fall, (R = 0.42), BMI in winter (R = 0.32), and BMI and tanning bed use in spring (R = 0.52). Study 2: Estimated Vitamin D intake from food was 186.4 ± 125.7 via FFLQ and 148.5 ± 228.2 IU/day via food diary. There was no association between intake estimated by the two methodologies (r = 0.12, p < 0.05). Conclusions: FFLQ-estimated vitamin D intake was not associated with serum 25(OH)D concentration or food-record-estimated vitamin D intake. Results highlight the difficulty of designing/utilizing intake methodologies for vitamin D, as its status is influenced by body size and both endogenous and exogenous (dietary) sources. [ABSTRACT FROM AUTHOR]

Bariatric surgery is associated with significant and sustained weight loss and improved metabolic outcomes. It is unclear if weight loss alone is the main mechanism of improved metabolic health. The purpose of this trial was to compare indices of appetite regulation, insulin sensitivity and energy intake (EI) between participants achieving 10 kg of weight loss via Roux‐en‐Y Gastric Bypass (RYGB) or dietary restriction (DIET); intake of a very low calorie liquid diet (800 kcal/d; 40% protein, 40% fat, 20% carbohydrate that matched the post‐RYGB dietary protocol). Adults qualifying for bariatric surgery were studied before and after 10 kg of weight loss (RYGB [n = 6]) or DIET [n = 17]). Appetite (hunger, satiety, and prospective food consumption [PFC]), appetite–related hormones, and metabolites (ghrelin, PYY, GLP‐1, insulin, glucose, free fatty acids [FFA], and triglycerides [TG]) were measured in the fasting state and every 30 min for 180 min following breakfast. Participants were provided lunch to evaluate acute ad libitum EI, which was similarly reduced in both groups from pre to post weight loss. Fasting ghrelin was reduced to a greater extent following RYGB compared to DIET (P = 0.04). Area under the curve (AUC) for ghrelin (P = 0.01), hunger (P < 0.01) and PFC (P < 0.01) increased after DIET compared to RYGB, following 10 kg weight loss. Satiety AUC increased after RYGB and decreased after DIET (P < 0.01). Glucose and insulin (fasting and AUC) decreased in both groups. FFA increased in both groups, with a greater increase in AUC seen after RYGB versus DIET (P = 0.02). In summary, appetite–related indices were altered in a manner that, if maintained, may promote a sustained reduction in energy intake with RYGB compared to DIET. Future work with a larger sample size and longer follow‐up will be important to confirm and extend these findings. RYGB altered appetite indices in a manner favoring continued energy restriction. DIET altered appetite indices in a manner favoring increased energy intake. Short‐term weight loss improved insulin sensitivity similarly in RYGB versus DIET. [ABSTRACT FROM AUTHOR]