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Effects of Plant-Based Diets on Weight Status: A Systematic Review.
Tran, E, Dale, HF, Jensen, C, Lied, GA
Diabetes, metabolic syndrome and obesity : targets and therapy. 2020;13:3433-3448
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Being overweight or obese is a huge risk factor for many detrimental conditions. It is estimated that around one-third of the world’s population will be overweight or obese by 2025. Hence there is a need to look at dietary strategies in the prevention and treatment of overweight and obesity. Plant-based diets have always existed, however interest in the topic has increased recently and more research is being done on the health-related effects of different plant-based diets. There are many reasons why someone might convert to a plant-based diet, possible health benefits such as weight management are among the most common. The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on body mass index and weight. The results suggest that plant-based diets may improve weight status in some patient groups. It should be noted that only one study out of the 19 included in the review had normal weight, clinically healthy participants. The study populations for the rest were overweight, obese or had type 2 diabetes. Future research should aim to include a representative study population and apply study diets without dietary restrictions.
Abstract
There is an increasing number of people who convert to a plant-based diet. The desire for health benefits, including weight management, is often a contributing factor behind this dietary choice. The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on body mass index and weight. A literature search was conducted in PubMed until December 2019. Twenty-two publications from 19 studies were included. The majority of them were randomized controlled trials comparing a low-fat vegan diet to an omnivore diet in participants with overweight, type 2 diabetes mellitus and/or cardiovascular disease. All studies reported weight reductions, of which seven revealed significant differences, and four revealed non-significant differences between the intervention and the control groups. The results suggest that plant-based diets may improve weight status in some patient groups. Due to restrictions in fat intake in many studies, followed by reduced energy intake, the effects of the different interventions differ depending on the specific plant-based diets investigated. Future research should aim to include a representative study population and apply study diets without dietary restrictions.
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Bariatric and metabolic surgery during and after the COVID-19 pandemic: DSS recommendations for management of surgical candidates and postoperative patients and prioritisation of access to surgery.
Rubino, F, Cohen, RV, Mingrone, G, le Roux, CW, Mechanick, JI, Arterburn, DE, Vidal, J, Alberti, G, Amiel, SA, Batterham, RL, et al
The lancet. Diabetes & endocrinology. 2020;8(7):640-648
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Bariatric surgery has been proven for weight loss in people with severe obesity. However, during the covid-19 pandemic, surgery has been postponed for many individuals. Under normal conditions, patients who are awaiting bariatric surgery are prioritised based on weight, however this does not necessarily reflect severity of their condition. This review paper aimed to develop new criteria in order to help prioritise individuals who are awaiting bariatric surgery. The authors began by reviewing the reasons for delaying bariatric surgery and the need for beds, the risks of covid-19 transmission during the procedure and the severe covid-19 complications that individuals with obesity can experience were discussed. A recommendation was made that all patients having bariatric surgery be tested for Covid-19. Solutions were proposed for those awaiting surgery such as diets, exercise, optimal blood sugar control and the potential use of weight loss medications. Prioritisation of surgery should focus on clinical need; it should be accessible and minimise harm from delays. Individuals with obesity and type 2 diabetes should be prioritised based on those who have an increased risk of death, determined by whether the individual; has poor blood sugar control despite maximal use of medications to control it, uses insulin, has previous heart disease, has liver disease or if they have other risk factors. It was concluded that weight alone is inadequate to prioritise candidates for bariatric surgery. Disease severity should be at the centre of decisions, especially when access to surgery is reduced, as is during the Covid -19 pandemic. This paper could be used by healthcare professionals to understand how to prioritise their obese and type 2 diabetic patients who are awaiting bariatric surgery.
Abstract
The coronavirus disease 2019 pandemic is wreaking havoc on society, especially health-care systems, including disrupting bariatric and metabolic surgery. The current limitations on accessibility to non-urgent care undermine postoperative monitoring of patients who have undergone such operations. Furthermore, like most elective surgery, new bariatric and metabolic procedures are being postponed worldwide during the pandemic. When the outbreak abates, a backlog of people seeking these operations will exist. Hence, surgical candidates face prolonged delays of beneficial treatment. Because of the progressive nature of obesity and diabetes, delaying surgery increases risks for morbidity and mortality, thus requiring strategies to mitigate harm. The risk of harm, however, varies among patients, depending on the type and severity of their comorbidities. A triaging strategy is therefore needed. The traditional weight-centric patient-selection criteria do not favour cases based on actual clinical needs. In this Personal View, experts from the Diabetes Surgery Summit consensus conference series provide guidance for the management of patients while surgery is delayed and for postoperative surveillance. We also offer a strategy to prioritise bariatric and metabolic surgery candidates on the basis of the diseases that are most likely to be ameliorated postoperatively. Although our system will be particularly germane in the immediate future, it also provides a framework for long-term clinically meaningful prioritisation.
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Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials.
Ge, L, Sadeghirad, B, Ball, GDC, da Costa, BR, Hitchcock, CL, Svendrovski, A, Kiflen, R, Quadri, K, Kwon, HY, Karamouzian, M, et al
BMJ (Clinical research ed.). 2020;369:m696
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Dietary recommendations to combat obesity and its associated risk for heart disease are extensive. Many different diets and patterns of eating are being tried by millions of people, however no systematic review comparing their effectiveness has been performed. This systematic review and meta-analysis aimed to determine the effectiveness of 14 popular diets and diets which restrict certain nutrients on weight loss and heart disease risk. The results identified 121 studies with 21942 patients for inclusion. The Atkins diet, the Zone diet and the Dietary Approaches to Stop Hypertension (DASH) diet were the most effective for weight loss and for reducing blood pressure. Low carbohydrate and low-fat diets achieved similar weight loss when compared to a normal diet. Low carbohydrate diets had less effect on heart disease risk factors than low fat and moderate macronutrient diets. There were no improvements in good cholesterol with any of the diets. Interestingly any benefits on weight loss for any of the diets disappeared after 12 months and this was also observed for heart disease risk, except in those on the Mediterranean diet. It was concluded that most diets show improvements to weight loss and heart disease risk factors over 6 months, however these are largely unsustainable after 12 months. Differences between diets are small and healthcare practitioners could use this study to recommend any number of diets to achieve weight loss and the Mediterranean diet in particular to decrease heart disease risk. However, it is important to understand that this may be a short-term fix and at 12 months patients need to be assessed to ensure that weight loss is sustained.
Abstract
OBJECTIVE To determine the relative effectiveness of dietary macronutrient patterns and popular named diet programmes for weight loss and cardiovascular risk factor improvement among adults who are overweight or obese. DESIGN Systematic review and network meta-analysis of randomised trials. DATA SOURCES Medline, Embase, CINAHL, AMED, and CENTRAL from database inception until September 2018, reference lists of eligible trials, and related reviews. STUDY SELECTION Randomised trials that enrolled adults (≥18 years) who were overweight (body mass index 25-29) or obese (≥30) to a popular named diet or an alternative diet. OUTCOMES AND MEASURES Change in body weight, low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, systolic blood pressure, diastolic blood pressure, and C reactive protein at the six and 12 month follow-up. REVIEW METHODS Two reviewers independently extracted data on study participants, interventions, and outcomes and assessed risk of bias, and the certainty of evidence using the GRADE (grading of recommendations, assessment, development, and evaluation) approach. A bayesian framework informed a series of random effects network meta-analyses to estimate the relative effectiveness of the diets. RESULTS 121 eligible trials with 21 942 patients were included and reported on 14 named diets and three control diets. Compared with usual diet, low carbohydrate and low fat diets had a similar effect at six months on weight loss (4.63 v 4.37 kg, both moderate certainty) and reduction in systolic blood pressure (5.14 mm Hg, moderate certainty v 5.05 mm Hg, low certainty) and diastolic blood pressure (3.21 v 2.85 mm Hg, both low certainty). Moderate macronutrient diets resulted in slightly less weight loss and blood pressure reductions. Low carbohydrate diets had less effect than low fat diets and moderate macronutrient diets on reduction in LDL cholesterol (1.01 mg/dL, low certainty v 7.08 mg/dL, moderate certainty v 5.22 mg/dL, moderate certainty, respectively) but an increase in HDL cholesterol (2.31 mg/dL, low certainty), whereas low fat (-1.88 mg/dL, moderate certainty) and moderate macronutrient (-0.89 mg/dL, moderate certainty) did not. Among popular named diets, those with the largest effect on weight reduction and blood pressure in comparison with usual diet were Atkins (weight 5.5 kg, systolic blood pressure 5.1 mm Hg, diastolic blood pressure 3.3 mm Hg), DASH (3.6 kg, 4.7 mm Hg, 2.9 mm Hg, respectively), and Zone (4.1 kg, 3.5 mm Hg, 2.3 mm Hg, respectively) at six months (all moderate certainty). No diets significantly improved levels of HDL cholesterol or C reactive protein at six months. Overall, weight loss diminished at 12 months among all macronutrient patterns and popular named diets, while the benefits for cardiovascular risk factors of all interventions, except the Mediterranean diet, essentially disappeared. CONCLUSIONS Moderate certainty evidence shows that most macronutrient diets, over six months, result in modest weight loss and substantial improvements in cardiovascular risk factors, particularly blood pressure. At 12 months the effects on weight reduction and improvements in cardiovascular risk factors largely disappear. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42015027929.
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Oral glutamine supplements reduce concurrent chemoradiotherapy-induced esophagitis in patients with advanced non-small cell lung cancer.
Chang, SC, Lai, YC, Hung, JC, Chang, CY
Medicine. 2019;98(8):e14463
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Non-small cell lung cancer (NSCLC) is commonly treated with concurrent chemo- and radiation therapy (CCRT). This treatment often causes acute radiation-induced oesophagitis (ARIE) which can lead to significant weight loss and unplanned treatment delays. This prospective randomised study assessed whether glutamine supplementation may prevent ARIE in advanced NSCLC patients. Patients were randomised to receive either standard treatment (CCRT) with prophylactic oral glutamine, 30 grams/day, or standard treatment alone. The patients in the glutamine group received glutamine for 1 year. Compared with the control group, the oral glutamine supplement group had significantly less severe ARIE, and in those patients who developed ARIE, onset was significantly delayed in the glutamine group. The incidence of weight loss was also significantly reduced in the glutamine group. There was no statistically significant difference in cancer progression-free survival between the two groups (median follow-up period 26.4 months). Glutamine supplementation was well tolerated by all patients. The authors conclude that oral glutamine supplementation has a benefit in delaying onset of and decreasing the severity of ARIE in advanced lung cancer patients undergoing CCRT.
Abstract
BACKGROUND Complications related to concurrent chemoradiotherapy (CCRT) such as acute radiation-induced esophagitis (ARIE) may cause significant morbidity and unplanned treatment delays in patients with advanced non-small cell lung cancer (NSCLC). We designed a prospective randomized study to assess the impact of glutamine (GLN) supplementation in preventing CCRT-induced toxicities of advanced NSCLC patients. METHODS From September 2014 to September 2015, 60 patients diagnosed with NSCLC were included to the study. Thirty patients (50%) received prophylactic powdered GLN orally at a dose of 10 g/8 h. The prescribed radiation dose to the planning target volume was 30 Gy in 2-Gy fractions. The endpoints were radiation-induced esophagitis, mucositis, body weight loss, overall survival and progression-free survival. RESULTS The 60 patients with NSCLC included 42 men and 18 women with a mean age ± standard deviation of 60.3 years ± 18.2 (range, 44-78 years).At a median follow-up of 26.4 months (range 10.4-32.2), all patients tolerated GLN well. A administration of GLN was associated with a decrease in the incidence of grade 2 or 3 ARIE (6.7% vs 53.4% for Gln+ vs Gln-; P = .004). GLN supplementation appeared to significantly delay ARIE onset for 5.8 days (18.2 days vs 12.4 days; P = .027) and reduced incidence of weight loss (20% vs 73.3%; P = .01). DISCUSSION Our study suggests a beneficial effect of oral glutamine supplementation for the prevention from radiation-induced injury and body weight loss in advanced NSCLC patients who receiving CCRT.
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Acceptability of a very-low-energy diet in Type 2 diabetes: patient experiences and behaviour regulation.
Rehackova, L, Araújo-Soares, V, Adamson, AJ, Steven, S, Taylor, R, Sniehotta, FF
Diabetic medicine : a journal of the British Diabetic Association. 2017;34(11):1554-1567
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Patients with type 2 diabetes can return to normal blood glucose levels through substantial weight loss. While many studies have addressed this, very few have assessed the effects of adherence to a very-low-energy diet (VLED) on patients’ quality of life. The aim of this study was to evaluate the experiences of adhering to VLED for patients in remission for type 2 diabetes. Fifteen participants were interviewed before and after the 8-week VLED intervention and narratives were analysed. This study identified common barriers, facilitators and strategies used by the participants. Overall, participants found adherence easier than anticipated, and found barriers to be offset by suggested behaviour-regulation strategies. Based on this study, the authors conclude dietary treatment for reversal of type 2 diabetes is acceptable and feasible in motivated patients, and suggest further controlled research be done to confirm the validity and applicability of these findings.
Abstract
AIMS: To evaluate the acceptability of an 8-week very-low-energy diet for remission of Type 2 diabetes, and to identify barriers and facilitators of adherence and behaviour-regulation strategies used by participants in the Counterbalance study. METHODS Eighteen of 30 participants in the Counterbalance study (ISRCTN88634530) took part in semi-structured interviews. Of these, 15 participants were interviewed before and after the 8-week very-low-energy diet intervention. Thematic analysis was used to analyse the narratives. RESULTS The prospect of diabetes remission, considerable weight loss, and long-term health improvement provided participants with substantial initial motivation. This motivation was sustained through the experience of rapid weight loss, improvements in blood glucose levels, social support and increased physical and psychological well-being. Overall, adherence to the very-low-energy diet for 8 weeks was perceived as much easier than anticipated, but required personal effort. Participants addressed challenges by removing food from the environment, planning, avoidance of tempting situations or places, and self-distraction. Weight loss and improvements in blood glucose levels lead to a sense of achievement and improvements in physical and psychological wellbeing. CONCLUSIONS Dietary treatment for reversal of Type 2 diabetes is acceptable and feasible in motivated participants, and the process is perceived as highly gratifying. Research outside of controlled trial settings is needed to gauge the generalisability of these findings.
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Treatment of Obesity: Weight Loss and Bariatric Surgery.
Wolfe, BM, Kvach, E, Eckel, RH
Circulation research. 2016;118(11):1844-55
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Individuals with obesity who have been unable to lose weight through non-surgical means may be candidates for bariatric surgery. Criteria was established over 20 years ago and stated that individuals with a BMI >40 and individuals with a BMI >35-40 with other related conditions who have failed to achieve weight loss medically, are appropriate for surgery. However, individuals with less severe obesity who have type 2 diabetes have now been highlighted as possible candidates also, indicating that it is an evolving process. This review of 123 papers focused on the indications, safety and reasons for bariatric surgery and its role in the reduction of heart disease. The reason for bariatric surgery is to achieve weight loss and decrease an individual’s risk of death and conditions associated with obesity. Indications for surgery were discussed and the types of surgery that are available. Safety has improved due to a number of changes such as recognition of experience of surgeons and centres, the enactment of care protocols and a switch to minimally invasive procedures. However less invasive surgeries appear to accomplish considerably less weight loss. Benefits to body fat, blood fat levels, high blood pressure, diabetes, non-alcoholic fatty liver disease, inflammation, the ability of the blood vessels to dilate and sleep apnoea were all discussed. These were all used as evidence to support the argument that surgery improves an individual’s chances of survival compared to lifestyle interventions, as sufficiently designed trials to support this have not been performed. It was concluded that bariatric surgery has greater improved heart disease and death compared to lifestyle interventions due to the significantly higher weight loss that results.
Abstract
This review focuses on the mechanisms underlying, and indications for, bariatric surgery in the reduction of cardiovascular disease (CVD), as well as other expected benefits of this intervention. The fundamental basis for bariatric surgery for the purpose of accomplishing weight loss is the determination that severe obesity is a disease associated with multiple adverse effects on health, which can be reversed or improved by successful weight loss in patients who have been unable to sustain weight loss by nonsurgical means. An explanation of possible indications for weight loss surgery as well as specific bariatric surgical procedures is presented, along with review of the safety literature of such procedures. Procedures that are less invasive or those that involve less gastrointestinal rearrangement accomplish considerably less weight loss but have substantially lower perioperative and longer-term risk. The ultimate benefit of weight reduction relates to the reduction of the comorbidities, quality of life, and all-cause mortality. With weight loss being the underlying justification for bariatric surgery in ameliorating CVD risk, current evidence-based research is discussed concerning body fat distribution, dyslipidemia, hypertension, diabetes mellitus, inflammation, obstructive sleep apnea, and others. The rationale for bariatric surgery reducing CVD events is discussed and juxtaposed with impacts on all-cause mortalities. Given the improvement of established obesity-related CVD risk factors after weight loss, it is reasonable to expect a reduction of CVD events and related mortality after weight loss in populations with obesity. The quality of the current evidence is reviewed, and future research opportunities and summaries are stated.
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The views of young children in the UK about obesity, body size, shape and weight: a systematic review.
Rees, R, Oliver, K, Woodman, J, Thomas, J
BMC public health. 2011;11:188
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Obesity in children is an increasing problem in Westernised societies; obese children are more at risk of poorer health in the short and long term. The aim of the study was to explore the views of children about the meanings of obesity and body size, shape or weight and their own experience of these issues. This systemic review looked at 28 studies done in UK, conducted after 1997 in children aged 4-11. The review’s findings suggest that for children, the health consequences of obesity seemed to be mostly irrelevant. Impact on their social lives was far more important. Also, despite often having healthy body sizes, children continue to dislike their own bodies. This review highlights the need to consider the social aspect of childhood obesity and that children’s perspectives should be used in the policy making process. The authors conclude that the studies did not fully represent children’s diversity and therefore higher quality research is needed to enable relevant interventions to be put into place.
Abstract
BACKGROUND There are high levels of concern about childhood obesity, with obese children being at higher risk of poorer health both in the short and longer terms. Children's attitudes to, and beliefs about, their bodies have also raised concern. Children themselves have a stake in this debate; their perspectives on this issue can inform the ways in which interventions aim to work.This systematic review of qualitative and quantitative research aimed to explore the views of UK children about the meanings of obesity and body size, shape or weight and their own experiences of these issues. METHODS We conducted sensitive searches of electronic databases and specialist websites, and contacted experts. We included studies published from the start of 1997 which reported the perspectives of UK children aged 4-11 about obesity or body size, shape or weight, and which described key aspects of their methods. Included studies were coded and quality-assessed by two reviewers independently.Findings were synthesised in two analyses: i) an interpretive synthesis of findings from open-ended questions; and ii) an aggregative synthesis of findings from closed questions. We juxtaposed the findings from the two syntheses. The effect of excluding the lowest quality studies was explored. We also consulted young people to explore the credibility of a subset of findings. RESULTS We included 28 studies. Instead of a focus on health, children emphasised the social impact of body size, describing experiences and awareness of abuse and isolation for children with a greater weight. Body size was seen as under the individual's control and children attributed negative characteristics to overweight people. Children actively assessed their own size; many wished their bodies were different and some were anxious about their shape.Reviewers judged that children's engagement and participation in discussion had only rarely been supported in the included studies, and few study findings had depth or breadth. CONCLUSIONS Initiatives need to consider the social aspects of obesity, in particular unhelpful beliefs, attitudes and discriminatory behaviours around body size. Researchers and policy-makers should involve children actively and seek their views on appropriate forms of support around this issue.