Weight cycling in a very low-calorie diet programme has no effect on weight loss velocity, blood pressure and serum lipid profile

Weight cycling based on altered immune microenvironment as a result of metaflammation

As a result of the obesity epidemic, more people are concerned about losing weight; however, weight regain is common, leading to repeated weight loss and weight cycling. The health benefits of early weight loss are nullified by weight regain after weight cycling, which has much more severe metabolic consequences. Weight cycling alters body composition, resulting in faster fat recovery and slower muscle reconstruction. This evident fat accumulation, muscle loss, and ectopic fat deposition destroy the intestinal barrier, increase the permeability of the small intestinal epithelium, and cause the lipotoxicity of lipid metabolites and toxins to leak into extraintestinal tissues and circulation. It causes oxidative stress and hypoxia in local tissues and immune cell infiltration in various tissues, all contributing to the adaptation to this metabolic change. Immune cells transmit inflammatory responses in adipose and skeletal muscle tissue by secreting cytokines and adipokines, which mediate immune cell pathways and cause metaflammation and inefficient metabolic degradation. In this review, we focus on the regulatory function of the immunological microenvironment in the final metabolic outcome, with a particular emphasis on the cellular and molecular processes of local and systemic metaflammation induced by weight cycling-induced changes in body composition. Metaflammation in adipose and muscle tissues that is difficult to relieve may cause weight cycling. As this chronic low-grade inflammation spreads throughout the body, metabolic complications associated with weight cycling are triggered. Inhibiting the onset and progression of metabolic inflammation and enhancing the immune microenvironment of adipose and muscle tissues may be the first step in addressing weight cycling.

The effect of weight regain on cardiometabolic health in children with obesity: A systematic review of clinical studies

AIMS

Children with obesity are treated by a lifestyle intervention to obtain weight loss. Nevertheless, weight regain often occurs. This systematic review examines the effect of weight regain on cardiometabolic health and summarizes these results in the metabolic syndrome prevalence as integrated endpoint.

DATA SYNTHESIS

A literature search was performed in PubMed and Web of Science. Studies were selected if they included participants aged <18 years with obesity and presented data before and after weight loss and after weight regain hereby reporting minimally 1 cardiovascular risk factor at every assessment. After screening, nine articles remained. Generally, the diastolic BP re-increased after weight regain, whereas for systolic BP a sustained result for 6 months was reported with an increase during longer follow-up. No significant changes in fasting glucose were reported after weight regain compared to baseline. Regarding triglycerides, a complete weight regain re-increased the lowered values to baseline, whereas a partial regain resulted in a sustained decrease in triglycerides in 2 studies and an increase to intermediate levels in 1 paper. HDL-cholesterol only rose several months after initiating treatment. Hs-CRP remained lowered for a longer period than the moment where the weight loss nadir was achieved.

CONCLUSION

Research on weight regain and cardiometabolic health in children with obesity is scarce. No convincing evidence was found for a worsening of the cardiometabolic profile after weight regain. Some benefits even persisted despite weight recovery. Subsequently, the metabolic syndrome prevalence seems temporarily lowered after weight loss, despite weight regain.

Physiological Responses of Post-Dietary Effects: Lessons from Pre-Clinical and Clinical Studies

Dieting regimens such as calorie restriction (CR) are among the most commonly practiced interventions for weight management and metabolic abnormalities. Due to its independence from pharmacological agents and considerable flexibility in regimens, many individuals turn to dieting as a form of mitigation and maintenance of metabolic health. While metabolic benefits of CR have been widely studied, weight loss maintenance and metabolic benefits are reported to be lost overtime when the diet regimen has been terminated—referred to as post-dietary effects. Specifically, due to the challenges of long-term adherence and compliance to dieting, post-dietary repercussions such as body weight regain and loss of metabolic benefits pose as major factors in the efficacy of CR. Intermittent fasting (IF) regimens, which are defined by periodic energy restriction, have been deemed as more flexible, compliant, and easily adapted diet interventions that result in many metabolic benefits which resemble conventional CR diets. Many individuals find that IF regimens are easier to adhere to, resulting in fewer post-dietary effects; therefore, IF may be a more effective intervention. Unfortunately, there is a severe gap in current research regarding IF post-dietary effects. We recognize the importance of understanding the sustainability of dieting; as such, we will review the known physiological responses of CR post-dietary effects and its potential mechanisms through synthesizing lessons from both pre-clinical and clinical studies. This review aims to provide insight from a translational medicine perspective to allow for the development of more practical and effective diet interventions. We suggest more flexible and easily practiced dieting regimens such as IF due to its more adaptable and practical nature.

Ketogenic diets as treatment of obesity and type 2 diabetes mellitus

During the last decades, several interventions for the management of overweight and obesity have been proposed. Among diets, the first studies focused on the effect of water only and total fasting diets with or without proteins. Unfortunately, they were found to be associated with adverse events which lead to the abandon of these strategies. Interestingly, despite the radical approach, total fasting was effective and generally well tolerated. A strict connection between protein-calorie malnutrition and increased in morbidity and mortality in hospitalized patients was found at that time. Then, the seminal works of Blackburn and his collaborators lead to the introduction of the protein-sparing modified fast. Encouraged by the early results using this intervention, diets evolved to the current very-low-calorie ketogenic diets (VLCKD). In the present review, results of studies on the VLCKDs are presented and discussed, with a particular reference to the protocolled VLCKD. Also, a recent proposal on the nomenclature on the ketogenic diets is reported. Available evidence suggests VLCKDs to be effective in achieving a rapid and significant weight loss by means of an easily reversible intervention which could be repeated, if needed. Muscle mass and strength are preserved, resting metabolic rate is not impaired, hunger, appetite and mood are not worsened. Symptoms and abnormal laboratory findings can be there, but they have generally been reported as of mild intensity and transient. Preliminary studies suggest VLCKDs to be a potential game-changer in the management of type 2 diabetes too. Therefore, VLCKDs should be considered as an excellent initial step in properly selected and motivated patients with obesity or type 2 diabetes, to be delivered as a part of a multicomponent strategy and under strict medical supervision.

Metabolic dysfunction following weight regain compared to initial weight gain in a high-fat diet-induced obese mouse model

Diet-induced weight loss and regain leads to physiological and metabolic changes, some of which are potentially harmful. However, the specific metabolic processes and dysfunctions associated with weight regain, and how they differ from initial weight gain, remain unclear. Thus, we examined the metabolic profiles of mice following weight regain compared to initial weight gain. Mice were fed a normal diet or a high-fat diet or were cycled between the two diets to alternate between obese and lean states. Liver samples were collected and hepatic metabolites were profiled using nuclear magnetic resonance (NMR). The identified metabolites associated with weight regain were quantified using gas chromatography/mass spectrometry (GC/MS) and lipid profiles were assessed using ultra-high-performance liquid chromatography-quadrupole time-of-flight MS (UPLC-QTOF-MS). In addition, changes in expression of pro-inflammatory cytokines and gluconeogenic enzymes were investigated using polymerase chain reaction (PCR) and western blotting, respectively. Hepatic levels of several amino acids were reduced in mice during weight regain compared with initial weight gain. In addition, gluconeogenic enzyme levels were increased following weight regain, indicating an up-regulation of gluconeogenesis. Lipidomic profiling revealed that levels of ceramide and sphingomyelin, which are related to obesity-induced inflammation, were significantly increased during weight regain compared to initial weight gain. Moreover, tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) levels were significantly up-regulated during weight regain. In this study, weight regains lead to an up-regulation of gluconeogenesis and aggravated inflammation. Additionally, weight regain can worsen the metabolic dysfunction associated with obesity.

A review and critique of published real-world weight management program studies

BACKGROUND

Beyond the essential but somewhat artificial conditions that typify formal clinical studies, real-world evidence (RWE) of weight loss program effectiveness is paramount for an accurate assessment of such programs and refinement of best practices.

OBJECTIVES

To evaluate the current state of RWE studies and publications on weight loss, identify the range of weight loss components being used in RWE programs, and to provide a general overview of the consistency or lack of consistency with regard to measuring and reporting outcomes.

METHODS

A structured search of PubMed was performed to identify relevant English-language publications from 2006 to December 2017 that reported real-world studies of weight loss among adults. Duplicates, non-relevant publications, articles on weight loss surgery, pediatric studies, randomized controlled trials, studies with self-reported weight loss, no objective weight measures, or that failed to include weight loss results were excluded.

RESULTS

This review included 62 RWE publications. Forty-nine studies included dietary intervention, 37 included exercise, 29 included motivational counseling, and 5 contained some patients who had pharmacologic treatment as part of their weight loss regimen. The numbers of participants per study ranged from 10 to more than 3 million. The interventions reported in the publications included diet, exercise, counseling to promote diet and/or exercise, motivational counseling, and pharmacotherapy, and various combinations of these.

CONCLUSIONS

Despite general acceptance that weight loss programs are capable of facilitating successful outcomes, this review revealed substantial inconsistency in the design and reporting of such programs, making it very difficult to draw conclusions about the comparative merits of different real-world weight loss strategies/components. In addition, there was a marked lack of congruence with current weight loss management guidelines, and notably few studies incorporating anti-obesity medications. There clearly is a need for greater rigor and standardization among designing and reporting RWE weight-loss studies.

A possible secondary immune response in adipose tissue during weight cycling: The ups and downs of yo-yo dieting

The field of immunometabolism is burgeoning, with hundreds of papers published on the topic each year. Our understanding of the contribution of immune cells to metabolic regulation has expanded from a simple idea of innate immune cells, such as macrophages, altering adipose tissue function in obesity, to an awareness of the complex role of adaptive immunity in many different organ systems. Recent findings have clearly demonstrated the presence of adaptive lymphocytes, such as T and B cells, in adipose tissue. Furthermore, these data demonstrated T-cell accumulation and limited T-cell receptor repertoire diversity in obese adipose tissue, indicating that an antigen-specific immune response may occur within this tissue. In a recently published paper, we reported that a mouse model of weight cycling resulted in increased T-cell accumulation in adipose tissue. In the current commentary, we discuss the possibility that this increase in adipose tissue T-cell number could represent a local secondary immune response to self-antigens exposed in adipose tissue during obesity. If further experimentation indicates that this hypothesis is true, these data will fortify the concept that obesity is a complex immune-mediated disease and would emphasize the importance of designing therapies to maintain weight loss.

Weight cycling increases T-cell accumulation in adipose tissue and impairs systemic glucose tolerance

Obesity is one of the leading causes of morbidity in the U.S. Accumulation of proinflammatory immune cells in adipose tissue (AT) contributes to the development of obesity-associated disorders. Weight loss is the ideal method to counteract the negative consequences of obesity; however, losses are rarely maintained, leading to bouts of weight cycling. Fluctuations in weight have been associated with worsened metabolic and cardiovascular outcomes; yet, the mechanisms explaining this potential correlation are not known. For determination of whether weight cycling modulates AT immune cell populations, inflammation, and insulin resistance, mice were subjected to a diet-switch protocol designed to induce weight cycling. Weight-cycled mice displayed decreased systemic glucose tolerance and impaired AT insulin sensitivity when compared with mice that gained weight but did not cycle. AT macrophage number and polarization were not modulated by weight cycling. However, weight cycling did increase the number of CD4(+) and CD8(+) T cells in AT. Expression of multiple T helper 1-associated cytokines was also elevated subsequent to weight cycling. Additionally, CD8(+) effector memory T cells were present in AT of both obese and weight-cycled mice. These studies indicate that an exaggerated adaptive immune response in AT may contribute to metabolic dysfunction during weight cycling.

Anthropometric, metabolic, psychosocial, and dietary characteristics of overweight/obese postmenopausal women with a history of weight cycling: a MONET (Montreal Ottawa New Emerging Team) study

Characteristics of weight cyclers have not been fully assessed. The objective of this study was to determine the anthropometric, metabolic, psychosocial, and dietary profile of postmenopausal women according to weight-cycling history, defined as the frequency of going on a diet and losing >10 kg: never (0 times), low (1 time), moderate (2 to 3 times), or frequent (> or = 4 times). The sample of this cross-sectional study consisted of 121 overweight/obese postmenopausal women enrolled in a 6-month randomized weight-loss intervention between 2003 and 2006. Measures at baseline were used to evaluate body composition (fat mass by dual-energy x-ray absorptiometry and visceral fat by computed tomography); resting metabolic rate by indirect calorimetry; insulin sensitivity by hyperinsulinemic-euglycemic clamp; fasting plasma levels of glucose, lipids, leptin, ghrelin, and adiponectin; blood pressure; psychosocial profile (eg, body-esteem, self-esteem, stress, perceived risks, perceived benefits, self-efficacy, quality of life, dietary restraint, disinhibition, hunger); and dietary profile (3-day food record). Differences among groups of weight cyclers were determined using analyses of variance. Among the 121 women, 15.7%, 24.8%, 33.9%, and 25.6% were non-, low, moderate, and frequent cyclers, respectively. Frequent cyclers were characterized by higher body mass index (calculated as kg/m(2)) (current and at 25 years of age) and percent body fat mass, larger waist circumference, and lower resting metabolic rate/kg body weight than noncyclers (P<0.05); and moderate cyclers had lower plasma adiponectin values than noncyclers (P<0.05). For psychosocial measures, frequent cyclers were characterized by greater disinhibition and lower body esteem after controlling for body mass index (P<0.05). In conclusion, weight cycling was found to be associated with some unfavorable metabolic and psychosocial parameters.