Content uploaded by Marie-Ève Leblanc
Author content
All content in this area was uploaded by Marie-Ève Leblanc on Jun 19, 2015
Content may be subject to copyright.
If not dieting, how to lose weight? Tips and tricks for a better global and cardiovascular health
Postgraduate Medicine
Abstract
Abstract Weight loss is a popular topic and may be of serious concern for many patients. Even with the abundant literature on obesity and cardiometabolic risk, it is always challenging to demystify and reinforce the determinants of safe approaches to lose weight. Measures of central obesity are essential to characterize the patient's adiposity distribution and should be part of the routine medical examination. Beyond this, screening for fasting lipids and glucose are important for the assessment of the cardiometabolic risk which may lead to increased cardiovascular morbidity and mortality. Differences in adiposity as well as in weight loss exist between sexes and should be taken into consideration. Rather than avoiding some food or following certain type of diet, any planned weight loss interventions should promote lifestyle and environmental modifications with healthy eating and appropriate physical activity. With clear objectives, this appears to be the best way in order to achieve weight loss goals permanently.
... In order to tackle the obesity epidemic, public policies worldwide have included the promotion of a healthy lifestyle, education in food choices and nutrition, and have underlined the importance of increasing time spent exercising (Leclerc et al., 2015). However, these strategies often fail to achieve sustained weight loss in the long term, mostly due to the difficulty for patients to adopt lifestyle changes and adhere to specific diets. ...
Introduction: Bile acids (BA) are cholesterol-derived molecules mostly known for their role in digesting lipids. By activating the Takeda G protein coupled receptor 5 (TGR5) in peripheral organs, they can also act as signaling molecules to reduce body weight and improve glucose homeostasis. Notably, TGR5 activation can increase energy expenditure in brown adipocytes, although the metabolic pathways involved in these effects are not yet clear. These outcomes imply an anti-obesity function for TGR5. However, all studies investigating BA in energy balance have exclusively focused on peripheral tissues. Since the major center of convergence of nutrient, hormonal, and environmental cues is the brain, particularly the hypothalamus, we hypothesized a role for TGR5 in this brain structure, suggesting that hypothalamic TGR5 activity may participate in energy balance, specifically under dietinduced obesity. Objective: To demonstrate the function of the BA – TGR5 system in hypothalamic populations known to control energy homeostasis, and disentangle its relevance for the treatment of diet-induced obesity. Methods: C57Bl6/J male mice that were either lean (standard chow) or diet-induced obese (60% high-fat diet; HFD) were implanted with an intra-cerebroventricular (ICV) cannula for the pharmacological delivery of TGR5 agonists. TGR5flox/flox mice were used to target the sitespecific deletion of the receptor within the mediobasal hypothalamus (MBH), through the stereotaxic delivery of AAV-Cre. The following metabolic outputs were measured: body weight, food intake, body composition (EchoMRI analyzer), insulin sensitivity, serum and hypothalamic BA (liquid mass spectrometry), and energy expenditure (TSE Phenomaster system). To block sympathetic signaling, we exposed mice to thermoneutrality (30°C) or performed chemical sympathectomy (6-hydroxydopamine; 80mg/kg i.p.). Markers of lipolysis, thermogenesis, and thyroid metabolism were measured in the liver, adipose and hypothalamic tissues by qPCR or western blots. All studies received the approval from the animal ethical committee of the University of Bordeaux. Results: We demonstrate that TGR5 and BA transporters are expressed in the MBH and that diet-induced obese mice have decreased circulating and hypothalamic BA. Acute ICV or intra-MBH administration of TGR5 agonists reduced food intake and body weight in dietinduced obese mice only, and improved insulin sensitivity. Accordingly, chronic ICV administration of the TGR5 agonist in obese mice reduced their body weight and adiposity, while increasing energy expenditure and mRNA markers of sympathetic activity in the adipose tissue. Indeed, experiments conducted at thermoneutrality or chemical sympathectomy blunted these effects, demonstrating that central TGR5 effects require an enhanced sympathetic tone. By using TGR5flox/flox mice coupled with the delivery of an AAVCre, we observed that the deletion of TGR5 in the MBH had no effect in chow-fed mice. However, a HFD switch rapidly increased their body weight, food intake and adiposity. When exposed to the cold (4 h at 4°C), protein levels of lipolysis and thermogenesis markers in the adipose tissue were blunted, implying an interruption in sympathetic signaling to the periphery due to hypothalamic downregulation of TGR5. Lastly, Cre-dependent deletion of TGR5 in the MBH of already obese mice rapidly increased adiposity by inducing hyperphagia, worsening their obese phenotype. Conclusions: Our work proves the existence of a functional hypothalamic BA – TGR5 receptor system. We show for the first time that the activation of TGR5 in the MBH decreases body weight and adiposity, while increasing energy expenditure through recruitment of the sympathetic nervous system. Taken together, these results expose a new mechanism of action for potential anti-obesity therapies.
... Obezite ve aşırı vücut ağırlığı olarak da bilinen aşırı yağlanma, Tip 2 diyabet, dislipidemi, kardiyovasküler hastalık, hipertansiyon ve kanser gibi farklı hastalık tipleri ile ilişkili olmaktadır (2). Birçok çalışma, popüler diyetlerin uzun vadede etki etmediğini açıkça göstermektedir (3). Öncelikli olarak kilo vermeye odaklanmak yerine, sağlıklı davranış değişikliği yapılması önerilmektedir. ...
Objectives
This study sought to examine the variation trends and seasonality of losing weight by using the data from Google Trends tool.
Methods
According to the search term of [lose weight + weight loss], Google Trends data were obtained. Search activity was conducted within the USA, the UK, Canada, Ireland, Australia, and New Zealand from January 01, 2004, to December 31, 2018, utilizing the health category.
Results
Dynamic series analysis and the plot of seasonal decomposition of time series show that relative search volume of [lose weight + weight loss] increased from 2004 to 2018 at both national and hemispherical levels. Statistically significant seasonal variations in relative search volume for the term [lose weight + weight loss] were observed using cosinor analyses in the USA (p < 0.001), the UK (p < 0.001), Canada (p < 0.001), Ireland (p < 0.001), Australia (p < 0.001), and New Zealand (p < 0.001), peaking in the spring months and reaching the lowest level in the autumn months. The highest level in spring and the lowest level in autumn were reversed by 6 months in both hemisphere countries, consistent with a seasonal pattern.
Conclusion
Our results indicate that Internet search queries for losing weight increased within the timeframe of 2004 to 2018, likely reflecting the rising global public interest. In addition, the present research provided preliminary evidence that there is a seasonality of losing weight with a peak in the spring months.
According to the sociocultural approach of eating pathology, the more women perceive sociocultural pressures about body image, the more they endorse society's beliefs related to thinness and obesity which in turn, is associated with greater body dissatisfaction. Also, the more dissatisfied women are about their body image, the more they report bulimic symptoms. In the present study, the same sequence of variables was tested with the addition of a Global Self-Determination variable to examine why sociocultural pressures are associated with bulimic symptomatology in only a subset of women. Participants (N = 300) consisted of female university students. Analyses revealed that the more women were globally self-determined towards the different aspects of their life, the less they perceived sociocultural pressures about body image, the less they endorsed society's beliefs related to thinness and obesity, and the less they experienced bulimic symptoms. These findings suggest that a global self-determined motivational profile in life could possibly act as a buffer against sociocultural influences about body image and decrease women's risk of experiencing bulimic symptoms.
Obesity is a major contributor to many chronic diseases and a risk factor for cardiovascular disease. It is also associated with increased risk of all-cause and cardiovascular disease (CVD) mortality. Toward the goals of the American College of Cardiology (ACC) and American Heart Association (AHA) for preventing CVD and promoting cardiovascular health, the ACC and AHA have collaborated with the National Heart, Lung, and Blood Institute and professional organizations to develop the "2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults". The 2013 guideline is the second edition of the 'Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: the Evidence Report' published in 1998. The new guideline maintains its focus on primary care practitioners (PCPs) and their patients in an effort to manage obesity more effectively and to reduce cardiovascular risk. The new guideline limits its scope by using five critical questions (CQs) and provides a summary of evidence-based recommendations and a treatment algorithm derived from the five CQs. The five CQs deal with the risks of overweight and obesity and the benefits of weight loss, and evaluate the following three treatment areas: diet, behavioral therapy, and surgical therapy. The recommendations and treatment algorithm serve as a guide for PCPs in the evaluation, prevention, and management of being overweight and obesity.
Cardiorespiratory fitness (CRF) is a strong determinant of morbidity and mortality. In athletes and the general population, it is established that high-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. This is a systematic review and meta-analysis to quantify the efficacy and safety of HIIT compared to MICT in individuals with chronic cardiometabolic lifestyle diseases.
The included studies were required to have a population sample of chronic disease, where poor lifestyle is considered as a main contributor to the disease. The procedural quality of the studies was assessed by use of a modified Physiotherapy Evidence Base Database (PEDro) scale. A meta-analysis compared the mean difference (MD) of preintervention versus postintervention CRF (VO2peak) between HIIT and MICT.
10 studies with 273 patients were included in the meta-analysis. Participants had coronary artery disease, heart failure, hypertension, metabolic syndrome and obesity. There was a significantly higher increase in the VO2peak after HIIT compared to MICT (MD 3.03 mL/kg/min, 95% CI 2.00 to 4.07), equivalent to 9.1%.
HIIT significantly increases CRF by almost double that of MICT in patients with lifestyle-induced chronic diseases.
Overweight and obesity affects more than 66% of the adult population and is associated with a variety of chronic diseases. Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies. Guidelines of the National Heart, Lung, and Blood Institute (NHLBI) encourage a 10% reduction in weight, although considerable literature indicates reduction in health risk with 3% to 5% reduction in weight. Physical activity (PA) is recommended as a component of weight management for prevention of weight gain, for weight loss, and for prevention of weight regain after weight loss. In 2001, the American College of Sports Medicine (ACSM) published a Position Stand that recommended a minimum of 150 min wk(-1) of moderate-intensity PA for overweight and obese adults to improve health; however, 200-300 min wk(-1) was recommended for long-term weight loss. More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss. To this end, we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain, for weight loss, and prevention of weight regain. Evidence supports moderate-intensity PA between 150 and 250 min wk(-1) to be effective to prevent weight gain. Moderate-intensity PA between 150 and 250 min wk(-1) will provide only modest weight loss. Greater amounts of PA (>250 min wk(-1)) have been associated with clinically significant weight loss. Moderate-intensity PA between 150 and 250 min wk(-1) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction. Cross-sectional and prospective studies indicate that after weight loss, weight maintenance is improved with PA >250 min wk(-1). However, no evidence from well-designed randomized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss. Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk. Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk. There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain.
Subcutaneous and visceral fat distribution as related to sex, age, and overweight was studied in 130 subjects and 10 women with Cushing's disease. Fat depots were evaluated by computed tomography at one thoracic and one abdominal level. Adipose tissue (density range −50 to 250 Hansfield units) was highlighted and the fat areas were measured by a laser planimeter. The ratio between subcutaneous and visceral fat areas (S:V ratio) was assumed as an index.
Ratios of both nonobese and obese groups were significantly higher in females than in males. Ratios decreased markedly over age 60. There was a significant inverse correlation between age and S:V ratios in females (r = 0.65; p < 0.001) and in males (r = 0.61; p < 0.001). Statistically significant correlations were found between S:V ratios at thoracic and abdominal levels. In Cushing's patients, the S:V ratio at the abdominal level was significantly lower than in controls matched for age, sex, and body mass index.
Pedometers are simple and inexpensive body-worn motion sensors that are readily being used by researchers and practitioners to assess and motivate physical activity behaviours. Pedometer-determined physical activity indices are needed to guide their efforts. Therefore, the purpose of this article is to review the rationale and evidence for general pedometer-based indices for research and practice purposes. Specifically, we evaluate popular recommendations for steps/day and attempt to translate existing physical activity guidelines into steps/day equivalents. Also, we appraise the fragmented evidence currently available from associations derived from cross-sectional studies and a limited number of interventions that have documented improvements (primarily in body composition and/or blood pressure) with increased steps/day. A value of 10 000 steps/day is gaining popularity with the media and in practice and can be traced to Japanese walking clubs and a business slogan 30+ years ago. 10 000 steps/day appears to be a reasonable estimate of daily activity for apparently healthy adults and studies are emerging documenting the health benefits of attaining similar levels. Preliminary evidence suggests that a goal of 10 000 steps/day may not be sustainable for some groups, including older adults and those living with chronic diseases. Another concern about using 10 000 steps/day as a universal step goal is that it is probably too low for children, an important target population in the war against obesity. Other approaches to pedometer-determined physical activity recommendations that are showing promise of health benefit and individual sustainability have been based on incremental improvements relative to baseline values. Based on currently available evidence, we propose the following preliminary indices be used to classify pedometer-determined physical activity in healthy adults: (i) 12 500 steps/day are likely to be classified as ‘highly active’.
To evaluate the daily steps threshold associated with improved cardiovascular disease risk factors during the first year following an acute coronary syndrome.
Subjects (N = 41) were recruited during hospitalization for an acute coronary syndrome. A blinded pedometer with a 7-day memory (NL-2000) was used at baseline, 3, 6, 9, and 12 months following hospitalization. Cardiovascular disease risk factors were measured at baseline, 6, and 12 months after discharge. Subjects who maintained a mean of 7500 steps per day or more at each time period were classified into the active group, whereas those who did not maintain this threshold were classified into the less active group.
The active group included 25 subjects, whereas 16 subjects were included in the less active group. Daily steps mean ± SEM was different between groups at 6 and 12 months followup (11 320 ± 3380 vs 5503 ± 1502 and 10 507 ± 2861 vs 6624 ± 3295 steps per day, respectively; both P < .001). Based on the analysis of variance for repeated measures (ANOVA-RM), the active group showed lower triglycerides (P < .01), lower waist circumference (P < .01), and higher high-density lipoprotein-cholesterol (HDL-C) (P = .04) at 12 months. Interaction effects (group × followup) were also significant for HDL-C (P = .01) and triglycerides (P = .01) after adjustment for age, gender, and baseline waist circumference.
Targeting ≥7500 daily steps during 1 year may be efficient to maintain lowest waist circumference and to improve lipid profile during the year following an acute coronary syndrome. It could be considered a starting target point to initiate changes in physical activity behavior.