Actual Weight Loss Research Articles

Actual weight loss trajectories after bariatric surgery compared with the SOPHIA prediction tool: An observational comparison study.

Estimation of post-bariatric surgery weight loss is important for informed clinical decisions, yet existing predictive models lack accuracy and reliability. We assessed the effectiveness of the validated Stratification of Obesity Phenotypes to Optimize Future Therapy (SOPHIA) bariatric weight trajectory prediction tool in our patient population. We conducted a retrospective study of 178 adults who underwent bariatric surgery over a 3-year period. Actual weights at baseline and annually over 5 years of follow-up were compared with predicted weights to calculate mean difference and median absolute deviation (MAD). The study comprised 157 women (88.2%) and 21 men (11.8%) with mean (standard deviation) age of 46.9 (10.6) years and baseline weight of 138.4 (23.5) kg. The bariatric surgical procedures included 148 (83.1%) gastric bypass, 19 (10.7%) sleeve gastrectomy and 11 (6.2%) gastric band operations. The proportion of patients with actual weights within the prediction interquartile range (IQR) was 50.7%, 43.2% and 38.8% at 12, 24 and 60 months, respectively. The mean difference between actual and predicted weight at 60 months was 0.6 (16.7) kg, p = 0.654 (paired t test). The mean MAD at 60 months was 12.9 (95% CI, 11.3-14.4) kg, indicating moderate predictive utility. The predictive accuracy was highest for gastric bypass. Subgroup analysis revealed greater accuracy in patients without diabetes/pre-diabetes, and in nonsmokers. The SOPHIA study tool provides accurate postoperative weight forecasts for some subgroups of patients, but its precision diminishes with time. This study reiterates the necessity for better personalized weight prediction tools to inform bariatric surgery decision-making.

A Novel Web App for Dietary Weight Management: Development, Implementation, and Usability Study.

Online weight loss programs have ambiguous efficacy. There is a growing body of evidence that weight loss programs when combined with apps have better outcomes; however, many apps lack an evidence-based approach to dietary changes for weight loss and do not rely on a theoretical framework for behavior change. This study aimed to describe the development and the preliminary usability and acceptability testing of a web app that uses behavior change techniques (BCTs) to support users of a comprehensive online weight loss program. The weight loss program intervention components were nutrient and weight tracking charts that needed a remotely accessible and online format. The app was designed by nutrition researchers and developers in a collaborative effort. A review of BCTs in weight loss and web apps was performed as well as an assessment of user needs to inform the initial prototype. A preliminary app prototype, version 1.0, was provided to participants of a weight loss trial (N=30) to assess for feasibility of its use. A full app prototype, version 2.0, was feasibility and acceptability tested by trial participants (n=11) with formal feedback by Likert-scale survey and open-ended questions. In the final round of testing, a user group of scientists and developers (n=11) was selected to provide a structured 3-month review through which the group met weekly for collective feedback sessions. The process resulted in a fully developed web app, MealPlot, by the Applied Research Institute, for meal planning and weight tracking that can be used by weight loss users and health professionals to track their patients. MealPlot includes a weight chart, a protein-fiber chart, and a chat feature. In addition, MealPlot has 2 distinct platforms, 1 for weight loss users and 1 for health professionals. Selected BCTs for incorporation into the app were goal setting, feedback, problem-solving, self-monitoring, and social support. Version 1.0 was used successfully to provide a functioning, online weight chart over the course of a 1-year trial. Version 2.0 provided a functional weight chart and meal planning page, but 8 out of 11 participants indicated MealPlot was difficult to use. Version 3.0 was developed based on feedback and strategies provided from user group testing. The web app, MealPlot, was developed to improve outcomes and functionality of an online weight loss program by providing a remote method of tracking weight, food intake, and connecting users to health professionals for consistent guidance that is not otherwise available in a traditional in-person health care setting. The final version 3.0 of the web app will be refined based on findings of a review study gathering feedback from health professionals and from actual weight loss users who are part of a clinical weight loss trial.

Physical Activity and Obesity - Underlying Mechanisms, Practical Actions

Individuals with obesity who undergo surgical or pharmacological therapies achieve good results in terms of weight and cardiometabolic risk reduction. It is not uncommon for those affected to equate the extent of weight loss achieved, with long-term treatment success. What is overlooked is that, in addition to obesity, significant weight loss also carries a risk of sarcopenia. Sarcopenic obesity and sarcopenia, in turn, increase the risk of cardiometabolic diseases. Physical activity has the potential to counteract cardiometabolic disease risk caused by obesity and sarcopenia. The underlying mechanism is contained in the endocrine organ skeletal muscle. The production and release of myokines in particular counteracts sarcopenic obesity and its complications. Physical activity is required to initiate myokine production. Endurance and strength training proves to be an effective training combination. In order to achieve a sustainable cardiometabolic risk reduction, the objectives and timing of physical activity should therefore be divided into two phases, a preparatory phase and an actual weight loss phase.

Machine Learning Analysis of Enhanced Biodegradable Phoenix dactylifera L./HDPE Composite Thermograms.

Worldwide, environmental groups and policymakers are focusing on waste recycling to create economic value and on the decomposition of waste by leveraging on scarce resources. This work, therefore, explores the thermal decomposition of enhanced biodegradable polymer matrices made from a mixture of discarded Phoenix dactylifera L./high-density polyethylene (PD/HDPE) using the machine learning analysis of experimental data. The experimental results of these samples were obtained via thermogravimetric (TGA) analysis under an oxidation-free environment, with heating rates of 10, 20, and 40 °C·min-1 and a degradation temperature range from 25 to 600 °C. The TGA analyses revealed the continued dependence of the actual percentage weight loss by these materials as a test function of the degradation temperature, shifting thermograms to temperature maxima consistent with increasing heating rates. Although high-density polyethylene (HDPE) materials were found to be thermally more stable than Phoenix dactylifera L. (PD) materials, PD/HDPE composite materials contained a significant amount of residual ash. Using a machine learning deep neural network approach for this process, significantly improved learning algorithms have been developed, which reduces the overall cost function (residual error) to almost zero (0.025) after just over a million iterations (epochs) and provides predictions that overlap with the experimental results (R2~1). Learning algorithms, along with optimized synaptic weights and biases, were employed to predict the behaviour of PD materials based on experimental thermograms conducted at higher degradation temperatures, typically ranging between 600 and 1000 °C. Predicted data using the enhanced learning algorithms completely overlapped the experiments (R2~1) for these higher degradation temperatures with near unity correlation if the decomposition of the materials continued until the residue was attained. With this approach, it is possible to predict and optimize the thermal characteristics of PD and HDPE with greater efficiency, which reduces the need for multiple design iterations and experimentation.

Adherence to Diet Advice Accelerates Weight Loss After 25 Days

Objective: To determine the relationship between the number of days of adherence to weight loss advice and actual weight loss. Methods: Weight loss tips were randomly assigned within broad categories to participants. Number of days of adherence and weight loss were then recorded. Tips were distributed through a popular weight loss related website. Participants were visitors to this website. The sample consists primarily of adult females, with a total of 180 participants. After answering some questions about their goals, individuals were assigned three tips to healthier eating habits. Follow-up surveys were administered at the end of each month thereafter. Results: Weight loss per day of adherence increases significantly after the 25th day of adherence. A day of adherence after the 25th day is more than 10 times more effective, resulting in nearly 0.5 pounds of weight loss as opposed to 0.04 pounds per day prior to the 25th day. Conclusion: Our results demonstrate the importance of long-lasting adherence in achieving weight loss. Given the nature of the weight loss tips involved, our results suggest that ease of adherence may be one of the most important factors in administering health advice to those wishing to lose weight.

Performance of a predictive weight loss model in terms of rapid detection of inadequate weight loss after Roux-en-Y gastric bypass

BackgroundPredictive weight loss models can help patients meet their expectations after bariatric surgery and assist physicians in responding to deviations from the predicted weight. A model published by Seyssel et al. appears to accurately predict postoperative body mass index. ObjectivesWe aimed to demonstrate this model’s performance in terms of rapid detection of insufficient weight loss (surgical nonresponse). SettingCantonal Hospital, Switzerland. MethodsWe retrospectively analyzed weight and body mass index deviations at 2 years postoperatively, based on values predicted by the model of Seyssel et al. The primary outcome was the timing of detection of surgical nonresponse. The secondary outcome was how patients’ weight loss expectations influenced their real weight loss. ResultsBetween 2016 and 2019, 190 patients underwent Roux-en-Y gastric bypass. Of these patients, 36 were lost to follow-up and 154 were included in this study. At 24 months, 16 patients had surgical nonresponse, defined as a real weight of +1 standard deviation higher than that predicted. Among these patients, 44% had a weight of ≥+1 standard deviation higher than predicted at 3 months, and 63% at 12 months. The positive and negative predictive values at 12 months were 59% and 95%, respectively. Patients with a lower hypothetically wanted weight (38.5%) exhibited greater weight loss (P < .05). ConclusionsThe predictive weight loss model of Seyssel et al. enables rapid detection of surgical nonresponse, allowing physicians to react as early as 3 months postsurgery. Patients’ overestimation of postoperative weight loss was positively correlated with the actual weight loss achieved.

Real-world data of a digitally enabled, time-restricted eating weight management program in public sector workers living with overweight and obesity in the United Kingdom: A service evaluation of the Roczen program.

The health of the United Kingdom workforce is key; approximately 186 million days are lost to sickness each year. Obesity and type 2 diabetes (T2D) remain major global health challenges. The aim of this retrospective service evaluation was to assess the impact of a digitally enabled, time-restricted eating (TRE) intervention (Roczen Program, Reset Health Ltd) on weight and other health-related outcomes. This service evaluation was conducted in people living with overweight/obesity, with 89% referred from public sector employers. Participants were placed on a TRE, low-carbohydrate, moderate protein plan delivered by clinicians and mentors with regular follow up, dietary guidance, goal setting, feedback, and social support. A total of 660 members enrolled and retention was 41% at 12months. The majority were female (73.2%), 58.9% were of White ethnicity, with a mean (SD) age of 47.5years (10.1), and a body mass index of 35.0kg/m2 (5.7). Data were available for 82 members at 12-month. At 12-month, members mean actual and percentage weight loss was -9.0kg (7.0; p<0.001) and -9.2% (6.7, p<0.001) respectively and waist circumference reduced by -10.3cm (10.7 p<0.001), with 45.1% of members achieving ≥10% weight loss. Glycated hemoglobin was significantly improved at 6months in people living with T2D (-11mmol/mol [5.7] p=0.012). Binge eating score significantly reduced (-4.4 [7.0] p=0.006), despite cognitive restraint increasing (0.37 [0.6] p=0.006). Our service evaluation showed that the Roczen program led to clinically meaningful improvements in body weight, health-related outcomes and eating behaviors that were sustained at 12-month.

Comparative effectiveness of glucagon-like peptide-1 receptor agonists for the management of obesity in adults without diabetes: A network meta-analysis of randomized clinical trials.

Tirzepatide is a new glucagon-like peptide-1 receptor agonist (GLP-1RA) that has shown promising results for weight loss. A Bayesian network meta-analysis was conducted to compare the efficacy and safety of GLP-1RAs for obesity management. Embase and MEDLINE were searched looking for randomized clinical trials (RCTs) that evaluated the efficacy of GLP-1RAs for weight loss in patients without diabetes. The main efficacy outcomes evaluated were the mean change in actual and percentage weight loss and the proportion of patients with weight loss of ≥5%-20%. Main safety outcomes evaluated include nausea, vomiting, diarrhea, constipation, loss of appetite, pancreatitis, gallbladder-related disorders, and withdrawal due to adverse events. Seven RCTs with more than 12,300 patients were analyzed, including patients with body mass index (BMI) ≥ 30 kg/m2 , or BMI ≥ 27 kg/m2 with comorbidities. Weekly tirzepatide 10 and 15 mg resulted in more weight loss than weekly semaglutide 2.4mg, daily semaglutide 0.4mg, or liraglutide 3mg. Tirzepatide and weekly semaglutide demonstrated comparable results but with significantly higher odds of achieving ≥5%-20% weight loss compared with liraglutide. GLP-1RAs triggered more gastrointestinal adverse events than placebo, with no in-between difference. Although all GLP-1RAs lead to significant weight reduction, tirzepatide was associated with better efficacy outcomes while having a comparable safety profile.

Predicting Early Weight Loss Failure Using a Bariatric Surgery Outcomes Calculator and Weight Loss Curves.

Weight loss after bariatric surgery can be accurately predicted using an outcomes calculator; however, outliers exist that do not meet the 1year post-surgery weight projections. Our goal was to determine how soon after surgery these outliers can be identified. We conducted a retrospective cohort study. Using a bariatric surgery outcomes calculator formulated by the Michigan Bariatric Surgery Collaborative (MBSC), predicted weight loss at 1year post-surgery was calculated on all patients who underwent primary bariatric surgery at a single-center academic institution between 2006 and 2015 who also had a documented 1-year follow-up weight (n = 1050). Weight loss curves were compared between high, low, and non-outliers as defined by their observed-to-expected (O:E) weight loss ratio based on total body weight loss (TBWL) %. Mean predicted weight loss for the study group was 39.1 ± 9.9kg, while mean actual weight loss was 39.7 ± 17.1kg resulting in a mean O:E 1.01 (± 0.35). Based on analysis of the O:E ratios at 1year post-surgery, the study group was sub-classified. Low outliers (n = 188, O:E 0.51) had significantly lower weight loss at 2months (13.1% vs 15.6% and 16.5% TBWL, p < 0. 001) and at 6months (19% vs 26% and 30% TBWL, p < 0.001) when compared to non-outliers (n = 638, O:E 1.00) and high outliers (n = 224, O:E 1.46), respectively. Weight loss curves based on individually calculated outcomes can help identify low outliers for additional interventions as early as 2months after bariatric surgery.

S1453 Weight Loss in Bariatric Surgery Patients Treated at a Novel Clinic Incorporating Obesity Medicine for Treatment of Nonalcoholic Fatty Liver Disease

Introduction: The Yale Fatty Liver Disease Program (YFLDP) is a patient care model incorporating weight management with standard hepatology care for targeted treatment of nonalcoholic fatty liver disease (NAFLD). Weight management is the mainstay treatment for NAFLD, with 10% total body weight loss (TBWL) leading to disease improvement. Bariatric surgery is an effective treatment for obesity and associated metabolic diseases, though only an estimated 1% of eligible patients receive referral nationwide. We studied YFLDP patient referral rates to bariatric surgery, clinical and surgical characteristics, and weight loss outcomes. Methods: We retrospectively extracted demographic, surgical, and weight loss outcome data of adult YFLDP patients from 10/2015 to 5/2022. Standard eligibility criteria included body mass index (BMI) >40 kg/m2 or >35 kg/m2 with an obesity-associated comorbidity. Actual 1-year weight loss outcomes were compared to predicted weight-loss outcomes calculated using the MBSAQIP Bariatric Surgical Risk/Benefit Calculator and assessed with a 2-tailed t-test. Results: There were 1,166 patients, of whom 596 (51.1%) were eligible for bariatric surgery (Table). Of these, 150 (25.3%) received referral, 32 patients (21.3%) underwent surgery (22 received sleeve gastrectomy (SG) and 10 had a Roux-en-Y gastric bypass [RYGB]). Patients who received surgery were more likely female and upper class compared to those who continued with lifestyle/medication management. Patients receiving SG and RYGB had mean TBWL 21.5% and 20.0%, respectively, while patients who continued medication/lifestyle management had TBWL of 3%. There was no significant difference comparing actual vs predicted final BMI (P=0.12), actual vs predicted weight loss (P=0.13), and actual vs predicted TBWL (P=0.13) post-bariatric surgery for all procedures (Figure). Conclusion: Integration of weight management with hepatology medical care is an effective model for NAFLD weight loss treatment. Patients receive referral for bariatric surgical evaluation at a rate 25 times greater than the national average, and those that receive surgery have comparable weight loss to that predicted in all patients receiving these surgeries, and on average exceeded the treatment threshold expected to treat NAFLD. Further study to identify patients who would most benefit from bariatric surgery would help to inform better patient selection and proactive referral efforts.Figure 1.: Predicted vs actual bariatric surgical outcomes in patients referred for surgery. (A) Actual vs Predicted Final Body Mass Index (BMI) post Bariatric Surgery: Comparison between YFLDP (Yale Fatty Liver Disease Program) patients’ actual BMI post bariatric surgery vs predicted BMI post bariatric surgery using the MBSAQIP Bariatric Surgical Risk/Benefit Calculator. There was no statistically significant difference between actual and predicted BMI (P=0.12). (B) Total Body Weight Loss (TBWL) in Patients given Bariatric Surgery Referral: Comparison between YFDLP patients’ total body weight % reduction in patients given a bariatric surgery referral who either underwent a gastric bypass or sleeve gastrectomy or did not have surgery and continued with lifestyle/medication management. Patients who underwent surgery had a statistically significant percent reduction in TBWL compared to patients managed with only lifestyle/medications. Error bars represent standard error. ***P< 0.001 Table 1. - Demographic and surgical characteristics of Yale Fatty Liver Disease Program patients who were referred for bariatric surgery Patient Characteristics Referred, Underwent Bariatric Surgery (+)(n=32) Referred, Did Not Undergo Bariatric Surgery (-)(n=118) P Sex n (%) Male 6 (19) 35 (30) 0.22 Female 26 (81) 83 (70) Age years (SD) 49 (10.3) 51 (12.98) 0.60 Medicare Qualifying n (%) 2 (6) 19 (12.98) 0.15 Race n (%) White 22 (69) 86 (73) 0.29 Black 4 (13) 15 (13) Asian 1 (3) 0 (0) Other/Declined 5 (15) 17 (14) Ethnicity n (%) Hispanic 6 (19) 27 (23) 0.62 Non-Hispanic 26 (81) 91 (77) Insurance Status n (%) Uninsured 0 (0) 0 (0) 0.045 Medicaid 14 (44) 31 (26) Medicare 2 (6) 27 (23) Private 16 (50) 60 (51) Median House Income by Zip Code n (%) < $50k 7 (22) 29 (25) 0.48 $50k-100k 19 (59) 75 (63) >$100k 6 (19) 14 (12) Anti-Obesity Medications n (%) Lifetime 16 (47) 38 (32) 0.78 Since YFLDP 10 (31) 29 (25) BMI Reduction mean (SD) RYGB (n=10) 8.3 (5.4) Predicted 1.3 (3.9) < 0.001 SG (n=22) 9.4 (6.1) < 0.001 TBWL % (SE) RYGB (n=10) 20.5 (3.5) Predicted 3 (0.8) < 0.001 SG (n=22) 21 (2.73) < 0.001 (+) Surgery denotes patients who underwent bariatric surgery after referral. (-) Surgery denotes patients who did not undergo bariatric surgery after referral. Patients who underwent bariatric surgery had statistically significant greater reduction in mean BMI compared to patients who did not have surgery. SD is standard deviation, SE is standard error, BMI is body mass index (kg/m2), RYGB is Roux-en-Y gastric bypass, SG is sleeve gastrectomy, TBWL is total body weight loss.

A262 Better than expected: Associations of positive discrepancy between expected and actual weight loss with early weight outcomes after metabolic and bariatric surgery

A262 Better than expected: Associations of positive discrepancy between expected and actual weight loss with early weight outcomes after metabolic and bariatric surgery

Self-Regulation and External Influence: The Relative Efficacy of Mobile Apps and Offline Channels for Personal Weight Management

On the basis of a novel panel data set on customers enrolled in an actual weight loss program that delivers services through a mobile app and offline stores, this study shows that use of the mobile app is positively associated with weight management by both free and paid users. For paid users, who have access to the mobile app and office visits, usage of both channels is associated with short-term weight loss. Furthermore, the two channels function as substitutes for one another, with users able to compensate for infrequent offline store visits through more intense mobile app usage. In the long term, however, only mobile app usage (and not offline store visits) contributes to the sustainability of weight loss. Additional empirical analyses further reveal that frequency and granularity of mobile app usage are positively associated with weight loss. We also find that individuals exposed to low performance pressure benefit more fully from mobile app usage. Overall, the empirical results, together with qualitative evidence gleaned from interviews with actual customers, suggest that mobile app usage and the self-regulation that it enables exert a relatively greater impact on personal weight management compared with the external influence stemming from human experts in offline channels.

The role of social support in obesity online health communities. A literature review

In the treatment of obesity, social support is considered key to successful weight loss and behavioural change, and online health communities to complement obesity treatment programmes have been shown to increase obesity treatment effectiveness. This study reviews the latest literature regarding how social support provided through an online health community can help people tackle obesity, identifying the different effects of social support on online health community members, specifically, the promotion of behavioural change and increased self-efficacy. This study also reveals how the recent literature points to both a direct and indirect relationship between social support in online health communities for obesity treatment and actual weight loss. This review is likely to provide useful insights to both healthcare professionals and social platform developers.

Outcomes following interventions to sustain body weight in esophageal cancer patients starting preoperative therapy: a retrospective cohort study.

BackgroundTo improve nutritional status and dysphagia, esophageal cancer patients starting neoadjuvant therapy in advance of curative-intent surgery may receive a jejunostomy tube (J-tube) or esophageal stent, or they may be managed without a feeding modality. We examined percent total weight loss (%TWL), reinterventions, and progression to surgery in relation to these options.MethodsThe retrospective cohort study included stage II–III esophageal cancer patients diagnosed during 2010–2017 who received J-tube, stent, or nutritional counseling only, without a procedure, when starting chemotherapy or combined modality chemoradiation. Data were obtained from the electronic medical record and chart review. We compared median %TWL between intervention groups and reinterventions using Chi-square and Kruskal-Wallis tests.ResultsAmong the 366 patients, median %TWL reached a nadir at 120 days, when it was 7% for patients with no procedure (N=307), 4% for J-tube (N=39), and 16% for stent (N=20) (P=0.01). Individual case analysis revealed 72–80% of the patients in the three groups started chemotherapy or chemoradiation as neoadjuvant curative-intent therapy (P difference =0.79). In J-tube patients, the reasons for intervention was anticipation of weight loss in 49% and mitigation of actual weight loss in 15%, whereas 95% of stent patients received the stent for dysphagia (P<0.001). A complication of the procedure was recorded in 85% of stent patients and 74% of J-tube patients (P<0.001). Among those who received no procedure initially, 25% received one later, compared with 15% of J-tube patients and 70% of stent patients who received a second procedure (P<0.001). Progression to surgery was observed in 65% of patients with no procedure, 51% of patients with J-tube, and 40% of stent patients, P=0.28).ConclusionsFor stage II–III esophageal cancer patients starting chemotherapy, this study gives evidence that stents were associated with significant %TWL and risk of reintervention. Although J-tube patients returned to baseline weight sooner than those with no procedure, they experienced complications from their J-tubes. For esophageal cancer patients undergoing curative-intent treatment and with acceptable levels of weight loss, no procedure at all may be superior to placing a J-tube in terms of complications, weight loss, and progression to curative-intent surgery.

Nutrition, age, medical literacy and gender: The impact of ethnic origin (Arabs vs. Jewish Israelis) on obesity

Summary Background Overweight and obesity are serious risk factors associated with major health problems such as, mortality as a result of ischemic heart diseases, cerebro vascular attacks (CVA) and diabetes. Previous cross-sectional research reveals the “Mediterranean diet” paradox among native Arab Israelis: despite the fact that this diet, rich in vegetables, fruits, high fiber and low fat diet originated in the Mediterranean basin, Israeli Arabs exhibit a high prevalence of obesity and concurrent elevated mortality rates. Yet, referring to the few obesity studies conducted among Arab-Israeli populations, none used a panel data-set. The Israeli longtitudinal survey was primarily conducted by the Israeli Central Bureau of Statistics (ICBS) at the national level beginning in 2012. This was part of the new statistical requirements from the Organization of Cooperation and Economic Development (OECD), which Israel joined as member in 2010. Objective To fill this lacuna, namely, lack of any previous longitudinal study in Israel at the national level. The panel structure of our study, covering 2012–2016, permits the BMI between-group comparison (as an overweight and obesity measure) of native Jewish and Arab Israelis females and males (the two main ethnic groups in Israel), while controlling the age variable within the same group. We track the same individuals over time and observe the variations of their BMI. Sample The sample employed in this study is representative of the Israeli population. The information was collected by personal interviews. The sample contains 24,685 observations × years of native Israelis, and is divided to 16,538 native Jewish Hebrew speakers × years (67% of the sample); and 8147 native non-Jewish Arabic speakers × years (33% of the sample). Results: Between-group comparison when age is controlled, compared to native Jewish Israeli women, native Jewish Israeli men and Arab Israeli women cross the overweight benchmark (i.e., BMI≥25 – according to the World Health Organization classification) 20 years earlier. Results: Within-group comparison while during this five-year period, native Arab Israeli women gain weight at an increasing pace, there is a decrease in the weight gain among native Jewish Israeli women, and starting from 2014 – there is an actual weight loss. Interestingly, during the sample period, both native Arab Israelis and Jewish Israeli men gained weight at an increasing pace. Conclusions These outcomes may demonstrate the higher medical literacy of native Jewish Israeli women (i.e., better awareness to high fiber diets and physical activity), and may stress the need to increase this public awareness, particularly among native Jewish Israeli men and both Arab Israeli men and women.

Interpretable Conditional Recurrent Neural Network for Weight Change Prediction: Algorithm Development and Validation Study.

BackgroundIn recent years, mobile-based interventions have received more attention as an alternative to on-site obesity management. Despite increased mobile interventions for obesity, there are lost opportunities to achieve better outcomes due to the lack of a predictive model using current existing longitudinal and cross-sectional health data. Noom (Noom Inc) is a mobile app that provides various lifestyle-related logs including food logging, exercise logging, and weight logging.ObjectiveThe aim of this study was to develop a weight change predictive model using an interpretable artificial intelligence algorithm for mobile-based interventions and to explore contributing factors to weight loss.MethodsLifelog mobile app (Noom) user data of individuals who used the weight loss program for 16 weeks in the United States were used to develop an interpretable recurrent neural network algorithm for weight prediction that considers both time-variant and time-fixed variables. From a total of 93,696 users in the coaching program, we excluded users who did not take part in the 16-week weight loss program or who were not overweight or obese or had not entered weight or meal records for the entire 16-week program. This interpretable model was trained and validated with 5-fold cross-validation (training set: 70%; testing: 30%) using the lifelog data. Mean absolute percentage error between actual weight loss and predicted weight was used to measure model performance. To better understand the behavior factors contributing to weight loss or gain, we calculated contribution coefficients in test sets.ResultsA total of 17,867 users’ data were included in the analysis. The overall mean absolute percentage error of the model was 3.50%, and the error of the model declined from 3.78% to 3.45% by the end of the program. The time-level attention weighting was shown to be equally distributed at 0.0625 each week, but this gradually decreased (from 0.0626 to 0.0624) as it approached 16 weeks. Factors such as usage pattern, weight input frequency, meal input adherence, exercise, and sharp decreases in weight trajectories had negative contribution coefficients of –0.021, –0.032, –0.015, and –0.066, respectively. For time-fixed variables, being male had a contribution coefficient of –0.091.ConclusionsAn interpretable algorithm, with both time-variant and time-fixed data, was used to precisely predict weight loss while preserving model transparency. This week-to-week prediction model is expected to improve weight loss and provide a global explanation of contributing factors, leading to better outcomes.

Rheological behavior, crystallization properties, and foaming performance of chain-extended poly (lactic acid) by functionalized epoxy.

The inherently linear poly (lactic acid) suffers unsatisfying foaming behavior due to its low melt strength and poor crystallization properties. To overcome this drawback, a random terpolymer of ethylene, acrylic ester and glycidyl methacrylate (EGMA) was employed to improve the rheological behavior, crystallization properties, and foaming performance of poly (lactic acid) (PLA) through a chain extension reaction. The branched/micro-crosslinked structure formed by the chain extension reaction between EGMA and PLA effectively improved the dynamic rheological properties of PLA. As the content of EGMA increased from 0 wt% to 20 wt%, the crystal nucleation and crystal growth rate of various PLA samples have been significantly accelerated, resulting in a larger number and smaller size of spherulites, and the crystallinity of various PLA samples increased from 7.9% to 38.54%. The cell size of various PLA foams decreased from 53.5 to 22.0 μm and the cell density increased from 3.5 × 106 cells per cm3 to 2.5 × 107 cells per cm3, meanwhile, the cellular morphology of PLA foam was obviously improved. Moreover, the actual weight loss of PLA foams reached 26.1%, which is higher than the theoretical weight loss.

Discrepancies between actual weight, weight perception and weight loss intention amongst persons with NAFLD

Currently, weight loss remains the main management strategy for NAFLD, but the weight loss intention and methods remain poorly characterized. We analysed data about the perception of weight status, intention and methods to lose weight amongst 3,822 persons with NAFLD (United States Fatty Liver Index≥30) from the National Health and Nutrition Examination Survey, 2001-2014. Only 53.9% of people with NAFLD intended to lose weight, 91.8% with perception of overweight and 8.2% with normal weight perception. Persons with perception of overweight or overweight/obese status were four times more likely to try to lose weight (adjusted odds ratios 3.9 and 4.2, respectively, both P<0.0001). Younger age, women, higher educational level, Hispanic and blacks (versus whites) were significant independent factors associated with weight loss intention. Notably, ≤10% attended weight loss programme. Metabolic equivalent of task hours per week was significantly higher in whites who exercised to lose weight (vs. no exercise, P=0.003) but not in other racial/ethnic groups. Interestingly, calorie intake was similar between those who dieted versus not (2056 vs. 1970kcal/day, P=0.11). About 30% reported≥10-lb weight loss, with 50% higher odds of success for men but there was no difference by race/ethnicity. Overweight or obese perception was a key driver in weight loss activities but was inconsistent with actual weight status and varied by race/ethnicity and other sociodemographic factors. Weight loss programme is under-utilized and should take in account of weight perception training and culturally appropriate approach.

Correlating actual one-year weight loss with predicted weight loss by the MBSAQIP: bariatric surgical risk/benefit calculator.

The American Society for Metabolic and Bariatric Surgery has released a Bariatric Surgical Risk/Benefit Calculator, an online tool with which patients and providers can input patient preoperative information and predict their 1-year weight loss. We seek to validate our institutional data with the national database and investigated patient factors that influence lack of treatment effect after bariatric surgery. A retrospective review of all prospectively collected data of bariatric surgeries performed at Yale New Haven Hospital from 2017 to 2018 was conducted. By entering data into the MBSAQIP Calculator, the 1-year predicted Body Mass Index was calculated and compared to the actual weight loss. Statistical analysis was performed using an unpaired t-test with Welch's correction (Prism 8, GraphPad). The average difference between the actual and predicted weight loss at 1-year for 327 patients was 3.6 BMI points. When the actual weight loss was compared to predicted BMI at 1year, a high correlation was found (R = 0.6, P = 0.003). We examined the outliers with a comparison of weight loss for those patients who's BMI fell within 5 points of the predicted versus those whose BMI recorded above 5. It was discovered those patients who had higher than 5 BMI points than predicted, had higher preoperative BMI (46.1 vs 43.6, P = 0.008). The MBSAQIP calculator is a useful tool to guide surgeons with decision-making and informed consent. Our institution's 1-year weight loss data correlated closely with that predicted. From the outliers, we found that patients who did not meet the predicted weight loss had significantly higher preoperative BMI. This may alter preoperative discussions with class 3 or over obese patients regarding expected weight loss and warrant investigations with the national database to develop modifications of the calculator.

Motivation and Weight Loss Expectations in Bariatric Surgery Candidates: Association with 1- and 2-Year Results After Bariatric Surgery.

There are discrepancies between patients' expected weight loss and what is considered achievable after bariatric surgery. This study describes the association between patients' expectations and actual weight loss, 1 and 2years postoperatively. A prospective observational study was performed. The association between expectations and actual weight loss (% total weight loss) was explored using linear regression analyses, adjusting for baseline demographics, surgery types, and self-esteem (Rosenberg self-esteem scale) and repeated separately per gender. Gender differences in motivations were explored using Chi-square tests. Of 440 patients at baseline, results on 368 (84%) at 1year and 341 (78%) patients at 2years were available. Significant and opposite associations were found when analyzing genders separately. There was a significant negative association between expectations and %TWL in men at 1year (β - 0.23, p = 0.04) and 2years postoperatively (β - 0.26, p = 0.03), indicating smaller weight loss for greater expectations. In women, a significant positive association (β 0.24, p < 0.01) was found 2years postoperatively, indicating greater weight loss for greater expectations. Both genders were mainly motivated by health concerns, but women were also motivated by reduced self-confidence to lose weight. Higher expectations were negatively associated with weight loss in men, but positively in women. This may be due to men being motivated by physical complaints, which improve with lower weight-loss. Women are also driven by reduced self-confidence, which may influence weight loss maintenance behaviors. Higher weight loss goals should not be considered as a contra-indication for surgery, but may be utilized to achieve patients' goals.