Objective
The brain's reward system influences ingestive behavior and subsequently obesity risk. Functional magnetic resonance imaging (fMRI) is a common method for investigating brain reward ...function. This study sought to assess the reproducibility of fasting‐state brain responses to visual food stimuli using BOLD fMRI.
Methods
A priori brain regions of interest included bilateral insula, amygdala, orbitofrontal cortex, caudate, and putamen. Fasting‐state fMRI and appetite assessments were completed by 28 women (n = 16) and men (n = 12) with overweight or obesity on 2 days. Reproducibility was assessed by comparing mean fasting‐state brain responses and measuring test‐retest reliability of these responses on the two testing days.
Results
Mean fasting‐state brain responses on day 2 were reduced compared with day 1 in the left insula and right amygdala, but mean day 1 and day 2 responses were not different in the other regions of interest. With the exception of the left orbitofrontal cortex response (fair reliability), test‐retest reliabilities of brain responses were poor or unreliable.
Conclusions
fMRI‐measured responses to visual food cues in adults with overweight or obesity show relatively good mean‐level reproducibility but considerable within‐subject variability. Poor test‐retest reliability reduces the likelihood of observing true correlations and increases the necessary sample sizes for studies.
Previously published findings from the Beef WISE Study (Beef's Role in Weight Improvement, Satisfaction, and Energy) indicated equivalent weight loss between two energy-restricted higher protein (HP) ...diets: A HP diet with ≥4 weekly servings of lean beef (B;
= 60) and a HP diet restricted in all red meats (NB;
= 60). Long-term adherence to dietary prescriptions is critical for weight management but may be adversely affected by changes in appetite, food cravings, and diet satisfaction that often accompany weight loss. A secondary
aim of the Beef WISE Study was to compare subjective ratings of appetite (hunger and fullness), food cravings, and diet satisfaction (compliance, satisfaction, and deprivation) between the diets and determine whether these factors influenced weight loss. Subjective appetite, food cravings, and diet satisfaction ratings were collected throughout the intervention, and body weight was measured at the baseline, after the weight loss intervention (week 16), and after an eight-week follow-up period (week 24). Hunger and cravings were reduced during weight loss compared to the baseline, while fullness was not different from the baseline. The reduction in cravings was greater for B vs. NB at week 16 only. Higher deprivation ratings during weight loss were reported in NB vs. B at weeks 16 and 24, but participants in both groups reported high levels of compliance and diet satisfaction with no difference between groups. Independent of group assignment, higher baseline hunger and cravings were associated with less weight loss, and greater diet compliance, diet satisfaction, and lower feelings of deprivation were associated with greater weight loss. Strategies to promote reduced feelings of hunger, cravings, and deprivation may increase adherence to dietary prescriptions and improve behavioral weight loss outcomes.
Nuts have high energy and fat contents, but nut intake does not promote weight gain or obesity, which may be partially explained by their proposed high satiety value. The primary aim of this study ...was to assess the effects of consuming almonds versus a baked food on postprandial appetite and neural responses to visual food stimuli. Twenty-two adults (19 women and 3 men) with a BMI between 25 and 40 kg/m² completed the current study during a 12-week behavioral weight loss intervention. Participants consumed either 28 g of whole, lightly salted roasted almonds or a serving of a baked food with equivalent energy and macronutrient contents in random order on two testing days prior to and at the end of the intervention. Pre- and postprandial appetite ratings and functional magnetic resonance imaging scans were completed on all four testing days. Postprandial hunger, desire to eat, fullness, and neural responses to visual food stimuli were not different following consumption of almonds and the baked food, nor were they influenced by weight loss. These results support energy and macronutrient contents as principal determinants of postprandial appetite and do not support a unique satiety effect of almonds independent of these variables.
Despite ongoing disagreement among the obesity research community, we have seemed to arrive at a paramount conclusion: there is no one-size-fits-all approach for weight loss. Thus, it is imperative ...to identify individual and contextual factors affecting intervention response. Emerging data suggests that pretreatment metabolic status may influence weight loss success. The aim of this scoping review is to describe the current state of knowledge on the effects of pretreatment glycemia and insulinemia status on weight loss regimens prescribing varying amounts and types of carbohydrates, time restricted eating (TRE), and exercise.
Twelve studies met inclusion criteria. Databases searched included PubMed, Web of Science, EMABSE, and ERIC. Reference lists of identified articles were also examined for additional studies. Studies were included if they were original peer-reviewed research and weight change was analyzed based on pretreatment glycemia and/or insulinemia status. Articles were excluded if they did not specify weight loss prescription or report weight loss outcomes.
People with high fasting plasma glucose (FPG) and type 2 diabetes at baseline tended to have greater weight loss carbohydrate-modified diets (e.g., high fiber, low glycemic load, and/or low carbohydrate). People with normoglycemia but elevated fasting insulin (FI) tended not to respond differently between diets. Thus, FPG and FI should be considered in combination for predicting weight loss outcomes among subgroups. TRE is efficacious for modest weight loss and ameliorating insulin resistance and may be especially useful for those with impaired glucose metabolism at baseline. We did not identify any studies investigating the effects of pretreatment glycemia and insulinemia status on weight loss achieved with exercise alone.
Pretreatment glycemia and insulinemia may be a promising strategy for predicting weight loss success, especially with low carbohydrate diets in those with impaired glucose metabolism. However, most of the available evidence is derived from retrospective analyses. Future prospective studies should be designed to directly investigate these effects and may also consider utilizing adaptive treatment strategies to tailor interventions to baseline metabolic status.
Supported by the General Mills Bell Institute of Health and Nutrition.
Objective
Weight loss of ≥10% improves glucose control and may remit type 2 diabetes (T2D). High‐protein (HP) diets are commonly used for weight loss, but whether protein sources, especially red ...meat, impact weight loss‐induced T2D management is unknown. This trial compared an HP diet including beef and a normal‐protein (NP) diet without red meat for weight loss, body composition changes, and glucose control in individuals with T2D.
Methods
A total of 106 adults (80 female) with T2D consumed an HP (40% protein) diet with ≥4 weekly servings of lean beef or an NP (21% protein) diet excluding red meat during a 52‐week weight loss intervention. Body weight, body composition, and cardiometabolic parameters were measured before and after intervention.
Results
Weight loss was not different between the HP (−10.2 ± 1.6 kg) and NP (−12.7 ± 4.8 kg, p = 0.336) groups. Both groups reduced fat mass and increased fat‐free mass percent. Hemoglobin A1c, glucose, insulin, insulin resistance, blood pressure, and triglycerides improved, with no differences between groups.
Conclusions
The lack of observed effects of dietary protein and red meat consumption on weight loss and improved cardiometabolic health suggests that achieved weight loss, rather than diet composition, should be the principal target of dietary interventions for T2D management.
Background
Bioelectrical impedance analysis (BIA) operates under the assumption that the conductor has a uniform cylindrical shape. However, this assumption may be violated if measures are taken in ...the seated position, especially in people with a high waist circumference (WC).
Aims
The aims of this research were to determine whether posture (supine, standing, and seated) and WC affect agreement between BIA and dual‐energy X‐ray absorptiometry (DXA) measures of fat mass (FM) and fat‐free mass (FFM).
Materials & Methods
Baseline data were collected from 28 adults (mean = 61.4 ± 6.9 years, 64.3% female) with obesity (BMI 38.6 ± 5.0 kg/m2). Body composition was measured using BIA in the supine, standing, and seated positions and by DXA while supine. Intraclass correlation coefficient (ICC) analyses with two‐way mixed effects and absolute agreement were performed to determine agreement.
Results
Point estimates were excellent for FM and FFM while supine, excellent for FM and good for FFM while standing, and moderate for FM and good for FFM while seated. BIA measures in the supine position resulted in the narrowest 95% confidence intervals compared with other positions. Better agreement was observed across all positions in participants with a WC below the median (118.3 cm).
Discussion
Despite the potential pragmatic value of measuring with BIA in a seated position, the results of this analysis demonstrate the poorest agreement between DXA and BIA methods, especially in individuals with high WC.
Conclusion
Findings from this study demonstrate that BIA, particularly when measured in a supine position, can serve as a viable alternative to DXA for measuring body composition in people with obesity.
Despite well-documented health benefits from exercise, a study on national trends in achieving the recommended minutes of physical activity guidelines has not improved since the guidelines were ...published in 2008. Peer interactions have been identified as a critical factor for increasing a population’s physical activity. The objective of this study is for establishing criteria for social influences on physical activity for establishing criteria that lead to exercise persistence. A system of differential equations was developed that projects exercise trends over time. The system includes both social and non-social influences that impact changes in physical activity habits and establishes quantitative conditions that delineate population-wide persistence habits from domination of sedentary behavior. The model was generally designed with parameter values that can be estimated to data. Complete absence of social or peer influences resulted in long-term dominance of sedentary behavior and a decline of physically active populations. Social interactions between sedentary and moderately active populations were the most important social parameter that influenced low active populations to become and remain physically active. On the other hand, social interactions encouraging moderately active individuals to become sedentary drove exercise persistence to extinction. Communities should focus on increasing social interactions between sedentary and moderately active individuals to draw sedentary populations to become more active. Additionally, reducing opportunities for moderately active individuals to engage with sedentary individuals through sedentary social activities should be addressed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
People with physical disabilities (PWD) participate in less physical activity than people without physical disabilities (PWoD), which increases the risk for several negative health consequences. ...Comparing physical activity between PWD and PWoD remains a challenge since no reliable and valid survey exists to measure physical activity in both populations. The International Physical Activity Questionnaire (IPAQ) was adapted to be inclusive of PWD using a recently developed survey adaption framework; however, the adapted IPAQ has not been assessed for reliability and validity. The objective of this study was to assess the reliability and validity of the adapted IPAQ.
To assess test-retest reliability, the adapted IPAQ was completed twice within a 72-hour period by 172 individuals (PWD: n = 102, PWoD: n = 70) and compared using intraclass correlation coefficients. Using Spearman rho, convergent validity and construct validity were assessed in 62 individuals by comparing the adapted IPAQ against the original instrument and activity monitor measured step count, respectively.
The adapted IPAQ demonstrated moderate test-retest reliability, with intraclass correlation coefficients of total scores for the total sample of .690 (95% confidence interval CI .581-.770) and among subgroup analysis (PWD, .640, 95% CI, .457-.761; PWoD, .758, 95% CI, .610-.850). Correlation coefficients were also good for the assessment of convergent validity of total score (.727; 95% CI, .579-.829; P < .001). Construct validity assessment yielded moderate coefficient (.406; 95% CI, .166-.596; P = .001).
The adapted IPAQ demonstrated acceptable reliability and validity and is appropriate for use in PWD and PWoD.
Background
Behavioral weight loss interventions can lead to an average weight loss of 5%–10% of initial body weight, however there is wide individual variability in treatment response. Although ...built, social, and community food environments can have potential direct and indirect influences on body weight (through their influence on physical activity and energy intake), these environmental factors are rarely considered as predictors of variation in weight loss.
Objective
Evaluate the association between built, social, and community food environments and changes in weight, moderate‐to‐vigorous physical activity (MVPA), and dietary intake among adults who completed an 18‐month behavioral weight loss intervention.
Methods
Participants included 93 adults (mean ± SD; 41.5 ± 8.3 years, 34.4 ± 4.2 kg/m2, 82% female, 75% white). Environmental variables included urbanicity, walkability, crime, Neighborhood Deprivation Index (includes 13 social economic status factors), and density of convenience stores, grocery stores, and limited‐service restaurants at the tract level. Linear regressions examined associations between environment and changes in body weight, waist circumference (WC), MVPA (SenseWear device), and dietary intake (3‐day diet records) from baseline to 18 months.
Results
Grocery store density was inversely associated with change in weight (β = −0.95; p = 0.02; R2 = 0.062) and WC (β = −1.23; p < 0.01; R2 = 0.109). Participants living in tracts with lower walkability demonstrated lower baseline MVPA and greater increases in MVPA versus participants with higher walkability (interaction p = 0.03). Participants living in tracts with the most deprivation demonstrated greater increases in average daily steps (β = 2048.27; p = 0.02; R2 = 0.039) versus participants with the least deprivation. Limited‐service restaurant density was associated with change in % protein intake (β = 0.39; p = 0.046; R2 = 0.051).
Conclusion
Environmental factors accounted for some of the variability (<11%) in response to a behavioral weight loss intervention. Grocery store density was positively associated with weight loss at 18 months. Additional studies and/or pooled analyses, encompassing greater environmental variation, are required to further evaluate whether environment contributes to weight loss variability.
Although built, social, and community food environments can have potential direct and indirect influences on body weight (through their influence on energy intake and physical activity), these environmental factors are rarely considered as predictors of variation in weight loss. This study examined the association between built, social, and community food environments and changes in weight, moderate‐to‐vigorous physical activity, and dietary intake among adults who completed an 18‐month behavioral weight loss intervention. Grocery store density was positively associated with weight loss at 18 months and participants living in less walkable neighborhoods had lower levels of moderate‐to‐vigorous physical activity at baseline but greater increases in moderate‐to‐vigorous physical activity at follow‐up.
Background
People with physical disabilities (PWD) have an increased risk of obesity and related comorbidities compared with people without physical disabilities (PWoD). Previously identified ...contributors to weight loss maintenance pose challenges to PWD. However, it is not known if PWD experience less success in weight management.
Methods
Six hundred and nine participants in the International Weight Control Registry (IWCR) were eligible for this analysis (PWD, n = 174; PWoD, n = 435). Self‐reported weight history metrics were compared using general linear models. Perceived weight history category was compared using Chi‐squared tests. Importance of diet and physical activity strategies for weight management were compared using Wilcoxon rank‐signed tests.
Results
PWD reported higher current body mass index (BMI) (36.1 ± 0.7 vs. 31.0 ± 0.5; p < 0.0001) and more weight loss attempts (9.1 ± 0.7 vs. 7.1 ± 0.4; p = 0.01) than PWoD. Current weight loss percentage (PWD 13.0 ± 1.0; PWoD, 13.0 ± 0.6; p = 0.97) and weight loss category (χ2 3, N = 609 = 2.9057, p = 0.41) did not differ between the groups. There were no differences in any weight strategy between PWD who were successful and those who regained.
Conclusions
PWD and PWoD in the IWCR achieved similar levels of weight maintenance success. However, higher BMI and more weight loss attempts suggest that PWD may face challenges with weight management. More research is needed to identify strategies leading to success for PWD.
People with physical disabilities (PWD) have an increased risk of obesity and related comorbidities compared with people without physical disabilities (PWoD). Previously identified contributors to weight loss maintenance pose challenges to PWD. This article explores weight history of PWD enrolled in the International Weight Control Registry to compare weight management efforts between PWD and PWoD.
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