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Journal: International journal of obesity (2005)

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By reducing energy density, low-energy sweeteners (LES) might be expected to reduce energy intake (EI) and body weight (BW). To assess the totality of the evidence testing the null hypothesis that LES exposure (versus sugars or unsweetened alternatives) has no effect on EI or BW, we conducted a systematic review of relevant studies in animals and humans consuming LES with ad libitum access to food energy. In 62 of 90 animal studies exposure to LES did not affect or decreased BW. Of 28 reporting increased BW, 19 compared LES with glucose exposure using a specific ‘learning’ paradigm. Twelve prospective cohort studies in humans reported inconsistent associations between LES use and Body Mass Index (-0.002 kg/m(2)/year, 95%CI -0.009 to 0.005). Meta-analysis of short-term randomized controlled trials (RCTs, 129 comparisons) showed reduced total EI for LES- versus sugar-sweetened food or beverage consumption before an ad libitum meal (-94 kcal, 95%CI -122 to -66), with no difference versus water (-2 kcal, 95%CI -30 to 26). This was consistent with EI results from sustained intervention RCTs (10 comparisons). Meta-analysis of sustained intervention RCTs (4 weeks to 40 months) showed that consumption of LES versus sugar led to relatively reduced BW (nine comparisons; -1.35 kg, 95%CI -2.28 to -0.42), and a similar relative reduction in BW versus water (three comparisons; -1.24 kg, 95%CI -2.22 to -0.26). Most animal studies did not mimic LES consumption by humans, and reverse causation may influence the results of prospective cohort studies. The preponderance of evidence from all human RCTs indicates that LES do not increase EI or BW, whether compared with caloric or non-caloric (e.g., water) control conditions. Overall, the balance of evidence indicates that use of LES in place of sugar, in children and adults, leads to reduced EI and BW, and possibly also when compared with water.International Journal of Obesity accepted article preview online, 14 September 2015. doi:10.1038/ijo.2015.177.

Concepts: Obesity, Evidence-based medicine, Systematic review, Randomized controlled trial, Mass, Body mass index, Meta-analysis, Calorie

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To examine the association of body mass index (BMI) with change in children’s physical activity and sedentary time between ages 6 and 11.

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The Daily Mile is designed to increase physical activity levels with children running or walking around school grounds for 15-min daily. It has been adopted by schools worldwide and endorsed as a solution to tackle obesity, despite no robust evidence of its benefits. We conducted a cluster randomised controlled trial to determine its clinical and cost-effectiveness.

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Influenza infects 5-15% of the global population each year, and obesity has been shown to be an independent risk factor for increased influenza-related complications including hospitalization and death. However, the risk of developing influenza or ILI in a vaccinated obese adult population has not been addressed.

Concepts: Biology, Demography, Population, Obesity, Childhood obesity, Adult, World population

36

With the increasing obesity epidemic comes the search for effective dietary approaches for calorie restriction and weight loss. I examine whether fasting is the latest ‘fad diet’ as portrayed in popular media and discuss whether it is a safe and effective approach or whether it is an idiosyncratic diet trend that promotes short-term weight loss, with no concern for long-term weight maintenance. Fasting has long been used in historical and experimental conditions and has recently been popularised by ‘intermittent fasting’, or, ‘modified fasting’ regimes, where by a very low calorie allowance is allowed, as alternate days (ADF) or 2 days a week (5:2 diet), where ‘normal’ eating is resumed on non-diet days. It is a simple concept, which makes it easy to follow with no difficult calorie counting every other day. This approach does seem to promote weight loss, but is linked to hunger, which can be a limiting factor for maintaining food restriction. The potential health benefits of fasting can be related to both the acute food restriction and chronic influence of weight loss; the long-term effect of chronic food restriction in humans is not yet clear, but may be a potentially interesting future dietary strategy for longevity, particularly given the overweight epidemic. One approach does not fit all to achieve body weight control, but this could be one dietary strategy for consideration.International Journal of Obesity accepted article preview online, 26 December 2014. doi:10.1038/ijo.2014.214.

Concepts: Nutrition, Obesity, Adipose tissue, Dieting, Calorie restriction, Fasting, Diets, Intermittent fasting

35

Despite theoretical evidence that the model commonly referred to as the 3500-kcal rule grossly overestimates actual weight loss, widespread application of the 3500-kcal formula continues to appear in textbooks, on respected government- and health-related websites, and scientific research publications. Here we demonstrate the risk of applying the 3500-kcal rule even as a convenient estimate by comparing predicted against actual weight loss in seven weight loss experiments conducted in confinement under total supervision or objectively measured energy intake. We offer three newly developed, downloadable applications housed in Microsoft Excel and Java, which simulates a rigorously validated, dynamic model of weight change. The first two tools available at http://www.pbrc.edu/sswcp, provide a convenient alternative method for providing patients with projected weight loss/gain estimates in response to changes in dietary intake. The second tool, which can be downloaded from the URL http://www.pbrc.edu/mswcp, projects estimated weight loss simultaneously for multiple subjects. This tool was developed to inform weight change experimental design and analysis. While complex dynamic models may not be directly tractable, the newly developed tools offer the opportunity to deliver dynamic model predictions as a convenient and significantly more accurate alternative to the 3500-kcal rule.

Concepts: Scientific method, Microsoft Excel, Statistics, Mathematics, Prediction, Science, Experiment, Spreadsheet

33

Coronavirus disease 2019 (COVID-19) and the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a particular risk to people living with preexisting conditions that impair immune response or amplify pro-inflammatory response. Low-grade chronic systemic inflammation, common in people with obesity, is associated with the development of atherosclerosis, type 2 diabetes, and hypertension, well known comorbidities that adversely affect the outcomes of patients with COVID-19. Risk stratification based on the Edmonton Obesity Staging System (EOSS), which classifies obesity based on the presence of medical, mental, and/or functional complications rather than on body mass index (BMI), has been shown to be a better predictor of all-cause mortality and it may well be that EOSS stages may better describe the risk of hyperinflammation in patients with COVID-19 infection. Analyzing a group of metabolic ill patients with obesity (EOSS 2 and 3), we found an increased interleukin-6 and linear regression analysis showed a positive correlation with C-reactive protein (CRP) (p = 0.014) and waist-to-hip-ratio (WHR) (p = 0.031). Physicians should be aware of these findings in patients with COVID-19 infection. Early identification of possible hyperinflammation could be fundamental and should guide decision making regarding hospitalization, early respiratory support, and therapy with immunosuppression to improve mortality.

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To examine the relation between long working hours and change in body mass index (BMI).

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Objective:To investigate the influence of adiposity on patterns of sex hormones across the menstrual cycle among regularly menstruating women.Subjects:The BioCycle Study followed 239 healthy women for 1-2 menstrual cycles, with up to eight visits per cycle timed using fertility monitors.Methods:Serum estradiol (E2), progesterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and sex hormone-binding globulin (SHBG) were measured at each visit. Adiposity was measured by anthropometry and by dual energy X-ray absorptiometry (DXA). Differences in hormonal patterns by adiposity measures were estimated using nonlinear mixed models, which allow for comparisons in overall mean levels, amplitude (i.e., lowest to highest level within each cycle) and shifts in timing of peaks while adjusting for age, race, energy intake and physical activity.Results:Compared with normal weight women (n=154), obese women (body mass index (BMI) 30 kg m(-2), n=25) averaged lower levels of progesterone (-15%, P=0.003), LH (-17%, P=0.01), FSH (-23%, P=0.001) and higher free E2 (+22%, P=0.0001) across the cycle. To lesser magnitudes, overweight women (BMI: 25-30, n=60) also exhibited differences in the same directions for mean levels of free E2, FSH and LH. Obese women experienced greater changes in amplitude of LH (9%, P=0.002) and FSH (8%, P=0.004), but no differences were observed among overweight women. Higher central adiposity by top compared to bottom tertile of trunk-to-leg fat ratio by DXA was associated with lower total E2 (-14%, P=0.005), and FSH (-15%, P=0.001). Peaks in FSH and LH occurred later (∼0.5 day) in the cycle among women with greater central adiposity.Conclusion:Greater total and central adiposity were associated with changes in mean hormone levels. The greater amplitudes observed among obese women suggest compensatory mechanisms at work to maintain hormonal homeostasis. Central adiposity may be more important in influencing timing of hormonal peaks than total adiposity.

Concepts: Obesity, Menopause, Estrogen, Luteinizing hormone, Body mass index, Estradiol, Menstrual cycle, Follicle-stimulating hormone

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Circulating angiotensin-converting enzyme (ACE) was identified as a predictor of weight loss maintenance in overweight/obese women of the Diogenes project.

Concepts: Cancer, Nutrition, Obesity, Physical exercise, Overweight, Adipose tissue, Dieting