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Frontiers in Endocrinology 2021Obesity is a complex multifactorial disease that accumulated excess body fat leads to negative effects on health. Obesity continues to accelerate resulting in an... (Review)
Review
Obesity is a complex multifactorial disease that accumulated excess body fat leads to negative effects on health. Obesity continues to accelerate resulting in an unprecedented epidemic that shows no significant signs of slowing down any time soon. Raised body mass index (BMI) is a risk factor for noncommunicable diseases such as diabetes, cardiovascular diseases, and musculoskeletal disorders, resulting in dramatic decrease of life quality and expectancy. The main cause of obesity is long-term energy imbalance between consumed calories and expended calories. Here, we explore the biological mechanisms of obesity with the aim of providing actionable treatment strategies to achieve a healthy body weight from nature to nurture. This review summarizes the global trends in obesity with a special focus on the pathogenesis of obesity from genetic factors to epigenetic factors, from social environmental factors to microenvironment factors. Against this background, we discuss several possible intervention strategies to minimize BMI.
Topics: Adipose Tissue; Animals; Body Mass Index; Body Weight; Energy Intake; Humans; Obesity; Risk Factors
PubMed: 34552557
DOI: 10.3389/fendo.2021.706978 -
International Journal of Environmental... Aug 2022A ketogenic diet, characterized by low calories with high levels of fat, adequate levels of protein, and low levels of carbohydrates, has beneficial effects on body... (Meta-Analysis)
Meta-Analysis Review
Ketogenic Diet Benefits to Weight Loss, Glycemic Control, and Lipid Profiles in Overweight Patients with Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trails.
A ketogenic diet, characterized by low calories with high levels of fat, adequate levels of protein, and low levels of carbohydrates, has beneficial effects on body weight control in overweight patients. In the present study, a meta-analysis was conducted to investigate the role of a ketogenic diet in body weight control and glycemic management in overweight patients with type 2 diabetes mellitus (T2DM). In summary, we systematically reviewed articles from the Embase, PubMed, Web of Science and Cochrane Library databases and obtained eight randomized controlled trials for meta-analysis. The results show that a ketogenic diet had significantly beneficial effects on the loss of body weight (SMD, -5.63, = 0.008), the reduction of waist circumference (SMD, -2.32, = 0.04), lowering glycated hemoglobin (SMD, -0.38, = 0.0008) and triglycerides (SMD, -0.36, = 0.0001), and increasing high-density lipoproteins (SMD, 0.28, = 0.003). Overall, these results suggest that a ketogenic diet may be an effective dietary intervention for body weight and glycemic control, as well as improved lipid profiles in overweight patients with T2DM. Hence, a ketogenic diet can be recommended for the therapeutic intervention of overweight patients with T2DM.
Topics: Blood Glucose; Body Weight; Diabetes Mellitus, Type 2; Diet, Ketogenic; Glycemic Control; Humans; Overweight; Triglycerides; Weight Loss
PubMed: 36012064
DOI: 10.3390/ijerph191610429 -
European Journal of Internal Medicine Nov 2021Weight regain following weight loss is frequent problem that people with obesity face. This weight recidivism is often attributed to the lack of compliance with... (Review)
Review
Weight regain following weight loss is frequent problem that people with obesity face. This weight recidivism is often attributed to the lack of compliance with appropriate food habits and exercise. On the contrary, it is known that body weight and fat mass are regulated by numerous physiological mechanisms, far beyond voluntary food intake and physical exercise. Thus, the aim of this paper is to review the main peripheral and central mechanisms involved in weight regain. Gut hormone secretion profiles impact upon predisposition to weight regain according to an individual variability, although it is recognised a usual pattern of compensatory changes: a reduction in anorectic hormones secretion and an increase in orexigenic hormone. These changes lead to both increased appetite and reward value of food leading to increased energye intake. In addition, resting energy expenditure after weight loss is lower than expected according to body composition changes. This gap between observed and predicted energy expenditure following weight loss is named metabolic adaptation, which has been suggested to explain partly weight regain. This complicated scenario, beyond patient motivation, makes weight regain a challenge in long-term management interventions in patients with obesity.
Topics: Body Weight; Energy Intake; Energy Metabolism; Humans; Obesity; Weight Gain; Weight Loss
PubMed: 33461826
DOI: 10.1016/j.ejim.2021.01.002 -
Gastroenterology May 2017Weight changes are accompanied by imbalances between calorie intake and expenditure. This fact is often misinterpreted to suggest that obesity is caused by gluttony and... (Review)
Review
Weight changes are accompanied by imbalances between calorie intake and expenditure. This fact is often misinterpreted to suggest that obesity is caused by gluttony and sloth and can be treated by simply advising people to eat less and move more. Rather various components of energy balance are dynamically interrelated and weight loss is resisted by counterbalancing physiological processes. While low-carbohydrate diets have been suggested to partially subvert these processes by increasing energy expenditure and promoting fat loss, our meta-analysis of 32 controlled feeding studies with isocaloric substitution of carbohydrate for fat found that both energy expenditure (26 kcal/d; P <.0001) and fat loss (16 g/d; P <.0001) were greater with lower fat diets. We review the components of energy balance and the mechanisms acting to resist weight loss in the context of static, settling point, and set-point models of body weight regulation, with the set-point model being most commensurate with current data.
Topics: Body Weight Maintenance; Diet; Energy Intake; Energy Metabolism; Exercise; Feedback, Physiological; Humans; Models, Biological; Obesity; Rest; Thermogenesis; Weight Loss
PubMed: 28193517
DOI: 10.1053/j.gastro.2017.01.052 -
Nutrients Apr 2022We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and... (Meta-Analysis)
Meta-Analysis
We conducted a systematic review and meta-analysis of randomized clinical trials and pilot trial studies to compare the effectiveness of intermittent fasting (IF) and continuous calorie restriction (CCR) in overweight and obese people. The parameters included body mass index (BMI), body weight, and other metabolism-related indicators. A systematic search in PubMed, Embase, Cochrane Library, and Web of Science was conducted up to January 2022. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to measure the effectiveness. Publication bias was assessed using Egger's test. The stability of the results was evaluated using sensitivity analyses. The significance of body weight change (SMD = -0.21, 95% CI (-0.40, -0.02) = 0.028) was more significant after IF than CCR. There was no significant difference in BMI (SMD = 0.02, 95% CI (-0.16, 0.20) = 0.848) between IF and CCR. These findings suggest that IF may be superior to CCR for weight loss in some respects.
Topics: Body Weight; Caloric Restriction; Fasting; Humans; Overweight; Weight Loss
PubMed: 35565749
DOI: 10.3390/nu14091781 -
Current Obesity Reports Dec 2016Metabolic adaptation to weight changes relates to body weight control, obesity and malnutrition. Adaptive thermogenesis (AT) refers to changes in resting and non-resting... (Review)
Review
Metabolic adaptation to weight changes relates to body weight control, obesity and malnutrition. Adaptive thermogenesis (AT) refers to changes in resting and non-resting energy expenditure (REE and nREE) which are independent from changes in fat-free mass (FFM) and FFM composition. AT differs in response to changes in energy balance. With negative energy balance, AT is directed towards energy sparing. It relates to a reset of biological defence of body weight and mainly refers to REE. After weight loss, AT of nREE adds to weight maintenance. During overfeeding, energy dissipation is explained by AT of the nREE component only. As to body weight regulation during weight loss, AT relates to two different set points with a settling between them. During early weight loss, the first set is related to depleted glycogen stores associated with the fall in insulin secretion where AT adds to meet brain's energy needs. During maintenance of reduced weight, the second set is related to low leptin levels keeping energy expenditure low to prevent triglyceride stores getting too low which is a risk for some basic biological functions (e.g., reproduction). Innovative topics of AT in humans are on its definition and assessment, its dynamics related to weight loss and its constitutional and neuro-endocrine determinants.
Topics: Body Composition; Diet, Reducing; Energy Metabolism; Humans; Obesity; Weight Gain; Weight Loss
PubMed: 27739007
DOI: 10.1007/s13679-016-0237-4 -
Seminars in Cancer Biology Jul 2023Excess body weight is a global health problem due to sedentary lifestyle and unhealthy diet, affecting 2 billion population worldwide. Obesity is a major risk factor for... (Review)
Review
Excess body weight is a global health problem due to sedentary lifestyle and unhealthy diet, affecting 2 billion population worldwide. Obesity is a major risk factor for metabolic diseases. Notably, the metabolic risk of obesity largely depends on body weight distribution, of which visceral adipose tissues but not subcutaneous fats are closely associated with obesity comorbidities, including type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and certain types of cancer. Latest multi-omics and mechanistical studies reported the crucial involvement of genetic and epigenetic alterations, adipokines dysregulation, immunity changes, imbalance of white and brown adipose tissues, and gut microbial dysbiosis in mediating the pathogenic association between visceral adipose tissues and comorbidities. In this review, we explore the epidemiology of excess body weight and the up-to-date mechanism of how excess body weight and obesity lead to chronic complications. We also examine the utilization of visceral fat measurement as an accurate clinical parameter for risk assessment in healthy individuals and clinical outcome prediction in obese subjects. In addition, current approaches for the prevention and treatment of excess body weight and its related metabolic comorbidities are further discussed.
Topics: Humans; Diabetes Mellitus, Type 2; Obesity; Comorbidity; Risk Factors; Diet
PubMed: 36965839
DOI: 10.1016/j.semcancer.2023.03.008 -
Journal of Basic and Clinical... Jan 2017The global prevalence of obesity has increased considerably in the last two decades. Obesity is caused by an imbalance between energy intake (EI) and energy expenditure... (Review)
Review
The global prevalence of obesity has increased considerably in the last two decades. Obesity is caused by an imbalance between energy intake (EI) and energy expenditure (EE), and thus negative energy balance is required to bring about weight loss, which can be achieved by either decreasing EI or increasing EE. Caffeine has been found to influence the energy balance by increasing EE and decreasing EI, therefore, it can potentially be useful as a body weight regulator. Caffeine improves weight maintenance through thermogenesis, fat oxidation, and EI. The sympathetic nervous system is involved in the regulation of energy balance and lipolysis (breakdown of lipids to glycerol and free fatty acids) and the sympathetic innervation of white adipose tissue may play an important role in the regulation of total body fat. This article reviews the current knowledge on the thermogenic properties of caffeine, and its effects on appetite and EI in relation to energy balance and body weight regulation.
Topics: Animals; Anti-Obesity Agents; Appetite; Body Weight; Caffeine; Energy Intake; Energy Metabolism; Humans; Obesity; Treatment Outcome
PubMed: 27824614
DOI: 10.1515/jbcpp-2016-0090 -
Obesity Facts 2021The very low-calorie ketogenic diet (VLCKD) has been recently proposed as an appealing nutritional strategy for obesity management. The VLCKD is characterized by a low... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The very low-calorie ketogenic diet (VLCKD) has been recently proposed as an appealing nutritional strategy for obesity management. The VLCKD is characterized by a low carbohydrate content (<50 g/day), 1-1.5 g of protein/kg of ideal body weight, 15-30 g of fat/day, and a daily intake of about 500-800 calories.
OBJECTIVES
The aim of the current document is to suggest a common protocol for VLCKD and to summarize the existing literature on its efficacy in weight management and weight-related comorbidities, as well as the possible side effects.
METHODS
This document has been prepared in adherence with Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. Literature searches, study selection, methodology development, and quality appraisal were performed independently by 2 authors and the data were collated by means of a meta-analysis and narrative synthesis.
RESULTS
Of the 645 articles retrieved, 15 studies met the inclusion criteria and were reviewed, revealing 4 main findings. First, the VLCKD was shown to result in a significant weight loss in the short, intermediate, and long terms and improvement in body composition parameters as well as glycemic and lipid profiles. Second, when compared with other weight loss interventions of the same duration, the VLCKD showed a major effect on reduction of body weight, fat mass, waist circumference, total cholesterol and triglyceridemia as well as improved insulin resistance. Third, although the VLCKD also resulted in a significant reduction of glycemia, HbA1c, and LDL cholesterol, these changes were similar to those obtained with other weight loss interventions. Finally, the VLCKD can be considered a safe nutritional approach under a health professional's supervision since the most common side effects are usually clinically mild and easily to manage and recovery is often spontaneous.
CONCLUSIONS
The VLCKD can be recommended as an effective dietary treatment for individuals with obesity after considering potential contra-indications and keeping in mind that any dietary treatment has to be personalized. Prospero Registry: The assessment of the efficacy of VLCKD on body weight, body composition, glycemic and lipid parameters in overweight and obese subjects: a meta-analysis (CRD42020205189).
Topics: Adult; Diet, Ketogenic; Humans; Obesity; Obesity Management; Overweight; Weight Loss
PubMed: 33882506
DOI: 10.1159/000515381 -
Obesity (Silver Spring, Md.) Aug 2016To measure long-term changes in resting metabolic rate (RMR) and body composition in participants of "The Biggest Loser" competition.
OBJECTIVE
To measure long-term changes in resting metabolic rate (RMR) and body composition in participants of "The Biggest Loser" competition.
METHODS
Body composition was measured by dual energy X-ray absorptiometry, and RMR was determined by indirect calorimetry at baseline, at the end of the 30-week competition and 6 years later. Metabolic adaptation was defined as the residual RMR after adjusting for changes in body composition and age.
RESULTS
Of the 16 "Biggest Loser" competitors originally investigated, 14 participated in this follow-up study. Weight loss at the end of the competition was (mean ± SD) 58.3 ± 24.9 kg (P < 0.0001), and RMR decreased by 610 ± 483 kcal/day (P = 0.0004). After 6 years, 41.0 ± 31.3 kg of the lost weight was regained (P = 0.0002), while RMR was 704 ± 427 kcal/day below baseline (P < 0.0001) and metabolic adaptation was -499 ± 207 kcal/day (P < 0.0001). Weight regain was not significantly correlated with metabolic adaptation at the competition's end (r = -0.1, P = 0.75), but those subjects maintaining greater weight loss at 6 years also experienced greater concurrent metabolic slowing (r = 0.59, P = 0.025).
CONCLUSIONS
Metabolic adaptation persists over time and is likely a proportional, but incomplete, response to contemporaneous efforts to reduce body weight.
Topics: Absorptiometry, Photon; Adult; Basal Metabolism; Body Composition; Body Mass Index; Body Weight; Female; Follow-Up Studies; Humans; Male; Middle Aged; Obesity, Morbid; Weight Loss
PubMed: 27136388
DOI: 10.1002/oby.21538