Association between weight cycling and risk of developing diabetes in adults: A systematic review and meta-analysis

Cardiometabolic characteristics of weight cycling: results from a mid-South regional comprehensive health care system

OBJECTIVE

The objective of this study was to determine the unique clinical and cardiometabolic risk characteristics of weight-cyclers and identify differences between weight-cyclers and individuals with other weight-change trajectories.

METHODS

A deidentified database of 1,428,204 Vanderbilt University Medical Center patients from 1997 to 2020 was included based on having ≥5 years of recorded weights. Patients with a history of malignant neoplasm, bariatric surgery, implausible BMI (e.g., <15 or >80 kg/m2), or missing documented height were excluded, yielding 83,261 participants categorized by weight trajectory, i.e., weight-stable, weight-gainer, weight-loser, or weight-cycler, based on criteria of ≥5% weight-change thresholds. Additionally, quartiles of average successive weight variability were evaluated to determine the effect of absolute differences among successive weight values.

RESULTS

Over half (55%) of participants were weight-cyclers, 23% were weight-gainers, 12% were weight-losers, and 10% were weight-stable over 5 years. Although baseline BMI did not differ among groups, weight-cyclers were more likely to have lower high-density lipoprotein cholesterol and higher blood glucose and triglyceride levels and to have been prescribed antihypertensive, dyslipidemia, and/or antidiabetic therapies. They were also younger and more likely to be smokers. Participants with the greatest weight variability (i.e., highest quartile of average successive weight variability) had higher cardiometabolic risk scores.

CONCLUSIONS

Weight cycling was highly prevalent but yielded no meaningful overall change in body weight after 5 years. These findings support a paradigm shift in weight management in individuals with overweight/obesity toward reducing cardiometabolic risk with or without weight loss.

Long-term weight patterns and physical activity in gallstones

While obesity, rapid weight loss, and sedentary lifestyles contribute to gallstones, the impacts of long-term weight patterns and physical activity on gallstone risk have not been extensively studied at the population level. Using Korea's population-based health database, we created a cohort of 5,062,154 subjects who received over five consecutive biannual health check-ups from 2002 to 2018. Gallstone risk was calculated using hazard ratios (HRs) based on weight patterns (gain, loss, and cycling) and physical activity. Adjustments were made for covariates, such as body mass index (BMI), waist circumference, diabetes, and life style factors. Subgroup analysis was performed by sex and age groups (< 45 and ≥ 45 years). All groups with weight changes showed increased HRs 1.32 (95% CI 1.07-1.65) for > 20% weight loss, 1.13 (0.96-1.33) for > 20% weight gain, 1.04 (1.02-1.06) for weight cycling, 1.03 (1.01-1.05) for 5-20% weight gain, and 1.02 (1.00-1.04) for 5-20% weight loss. Risk increased with weight loss or gain in underweight or overweight BMI categories, respectively, and in any weight change for normal BMI. Males and older individuals had higher risks with weight loss, while females and younger individuals had higher risks with weight gain. Weight cycling increased risk for both sexes. Regular physical activity reduced gallstone risk in weight changers to levels similar to weight maintainers, with the highest reduction in those with > 20% weight gain (61%) and the lowest in weight cycling (1%). The risks of gallstones associated with weight gain, loss, or cycling can be mitigated by regular physical activity. The risks vary by sex and age.

Accounting for time-varying exposures and covariates in the relationship between obesity and diabetes: analysis using parametric g-formula

BACKGROUND

Previous studies investigating the association between obesity and diabetes often did not consider the role of time-varying covariates affected by previous obesity status. This study quantified the association between obesity and diabetes using parametric g-formula.

METHODS

We included 8924 participants without diabetes from the Korean Genome and Epidemiology Study-Ansan and Ansung study(2001-2002)-with up to the seventh biennial follow-up data from 2015 to 2016. Obesity status was categorised as normal (body mass index (BMI) <23.5 kg/m2), overweight (23.5-24.9 kg/m2), obese 1 (25.0-27.4 kg/m2) and obese 2 (≥27.5 kg/m2). Hazard ratios (HRs) comparing baseline or time-varying obesity status were estimated using Cox models, whereas risk ratio (RR) was estimated using g-formula.

RESULTS

The Cox model for baseline obesity status demonstrated an increased risk of diabetes in overweight (HR 1.85; 95% CI=1.48-2.31), obese 1 (2.40; 1.97-2.93) and obese 2 (3.65; 2.98-4.47) statuses than that in normal weight status. Obesity as a time-varying exposure with time-varying covariates had HRs of 1.31 (1.07-1.60), 1.55 (1.29-1.86) and 2.58 (2.14-3.12) for overweight, obese 1 and obese 2 statuses. Parametric g-formula comparing if everyone had been in each obesity category versus normal over 15 years showed increased associations of RRs of 1.37 (1.34-1.40), 1.78 (1.76-1.80) and 2.42 (2.34-2.50).

CONCLUSIONS

Higher BMI classification category was associated with increased risk of diabetes after accounting for time-varying covariates using g-formula. The results from g-formula were smaller than when considering baseline obesity status only but comparable with the results from time-varying Cox model.

Yoyo Dieting, Post-Obesity Weight Loss, and Their Relationship with Gut Health

Excessive body weight is associated with many chronic metabolic diseases and weight loss, so far, remains the gold standard treatment. However, despite tremendous efforts exploring optimal treatments for obesity, many individuals find losing weight and maintaining a healthy body weight difficult. Weight loss is often not sustainable resulting in weight regain and subsequent efforts to lose weight. This cyclic pattern of weight loss and regain is termed "yoyo dieting" and predisposes individuals to obesity and metabolic comorbidities. How yoyo dieting might worsen obesity complications during the weight recurrence phase remains unclear. In particular, there is limited data on the role of the gut microbiome in yoyo dieting. Gut health distress, especially gut inflammation and microbiome perturbation, is strongly associated with metabolic dysfunction and disturbance of energy homeostasis in obesity. In this review, we summarise current evidence of the crosstalk between the gastrointestinal system and energy balance, and the effects of yoyo dieting on gut inflammation and gut microbiota reshaping. Finally, we focus on the potential effects of post-dieting weight loss in improving gut health and identify current knowledge gaps within the field, including gut-derived peptide hormones and their potential suitability as targets to combat weight regain, and how yoyo dieting and associated changes in the microbiome affect the gut barrier and the enteric nervous system, which largely remain to be determined.

Adiposity, type 2 diabetes and atherosclerotic cardiovascular disease risk: Use and abuse of the body mass index

The worldwide prevalence of individuals with an elevated body weight has increased steadily over the past five decades. Billions of research dollars have been invested to improve our understanding of the causes and consequences of having an elevated body weight. All this knowledge has, however, failed to influence populational body weight trajectories of most countries around the world. Research on the definition of "obesity" has also evolved. Body mass index (BMI), the most commonly used tool to make its diagnosis, has major limitations. In this review article, we will highlight evidence from observational studies, genetic association studies and randomized clinical trials that have shown the remarkable inter-individual differences in the way humans store energy as body fat. Increasing evidence also suggests that, as opposed to weight inclusive, lifestyle-based approaches, weight-centric approaches advising people to simply eat less and move more are not sustainable for most people for long-term weight loss and maintenance. It is time to recognize that this outdated approach may have produced more harm than good. On the basis of pathophysiological, genetic and clinical evidence presented in this review, we propose that it may be time to shift away from the traditional clinical approach, which is BMI-centric. Rather, emphasis should be placed on actionable lifestyle-related risk factors aiming at improving overall diet quality and increasing physical activity level in the general population.

Dissecting the biology of feeding and eating disorders

Feeding and eating disorders (FEDs) are heterogenous and characterized by varying patterns of dysregulated eating and weight. Genome-wide association studies (GWASs) are clarifying their underlying biology and their genetic relationship to other psychiatric and metabolic/anthropometric traits. Genetic research on anorexia nervosa (AN) has identified eight significant loci and uncovered genetic correlations implicating both psychiatric and metabolic/anthropometric risk factors. Careful explication of these metabolic contributors may be key to developing effective and enduring treatments for devastating, life-altering, and frequently lethal illnesses. We discuss clinical phenomenology, genomics, phenomics, intestinal microbiota, and functional genomics and propose a path that translates variants to genes, genes to pathways, and pathways to metabolic outcomes to advance the science and eventually treatment of FEDs.

Body composition as a marker of performance and health in military personnel

Introduction

Body composition standards are set to ensure operational readiness in active-duty military personnel. To meet body composition standards, some individuals, however, may engage in unhealthy weight control behaviors (i.e., weight cycling and disordered eating). The objectives of this review are to: (1) evaluate the evidence regarding body composition and the associations to physical and military specific performance; (2) discuss body composition and potential health consequences; and (3) examine the evidence of weight cycling and disordered eating behaviors in military personnel for weight control.

Methods

A systematic search to identify peer-reviewed research articles was conducted in PubMed on 2/20/2023 using Medical Subject Headings (MeSH) including but not limited to "Military Personnel", "Tactical Athlete", "Weight Loss", "Body Composition", and "Weight Cycling".

Results

A total of 225 research articles were identified. The list was narrowed down to articles from the last 20 years (2003-2023) in military personnel. Only studies in which percent body fat was directly measured were included resulting in 17 research articles for this review.

Discussion

Evidence-based research is limited on the relationship between body composition and operational readiness. Weight cycling and disordered eating behaviors also has been reported for weight control, yet additional research is needed. Specifically, future research should focus on female service members, racial and ethnic differences, age, and postpartum status and include other service branches (i.e., Air Force and Navy). A comprehensive survey on weight cycling, disordered eating, and weight management would be valuable to determine the prevalence and extent of this issue. This information along with performance data would guide policy makers on the relevance and appropriateness of existing body composition standards.

Weight-cycling over 6 years is associated with pain, physical function and depression in the Osteoarthritis Initiative cohort

Body weight significantly impacts health and quality of life, and is a leading risk factor for the development of knee osteoarthritis (OA). Weight cycling may have more negative health consequences compared to steady high or low weight. Using the Osteoarthritis Initiative dataset, we investigated the effects of weight cycling on physical function, quality of life, and depression over 72-months compared to stable or unidirectional body weight trajectories. Participants (n = 731) had knee OA and were classified as: (1) stable-low (BMI < 25), (2) stable-overweight (BMI = 25-29.9), and (3) stable-obese (BMI ≥ 30); (4) steady-weight-loss; (5) steady-weight-gain (weight loss/gain ≥ 2.2 kg every 2-years); (6) gain-loss-gain weight cycling, and (7) loss-gain-loss weight cycling (weight loss/gain with return to baseline), based on bi-annual assessments. We compared Knee Injury and Osteoarthritis Outcome Knee-Related Quality of Life, Function in Sports and Recreation, Physical Activity in the Elderly, Short Form SF-12, repeated chair rise, 20-m gait speed, and Center for Epidemiological Studies Depression using repeated-measures ANOVA. The steady weight loss group demonstrated the worst pain, physical function, and depressive symptoms over time (p's < 0.05). More research is needed to confirm these findings, and elucidate the mechanisms by which steady weight loss is associated with functional decline in knee OA.

Investigating the efficacy and feasibility of using a whole-of-diet approach to lower circulating levels of C-reactive protein in postmenopausal women: a mixed methods pilot study

OBJECTIVE

Chronic inflammation is associated with obesity and is an underlying pathophysiology for cardiovascular disease (CVD) development in postmenopausal women. This study aims to determine feasibility and efficacy of an anti-inflammatory dietary intervention to lower levels of C-reactive protein in weight stable postmenopausal women with abdominal obesity.

METHODS

This mixed-methods pilot study used a single arm pre-post design. Thirteen women followed a 4-week anti-inflammatory, dietary intervention, optimizing consumption of healthy fats, low glycemic index wholegrains, and dietary antioxidants. Quantitative outcomes included change in inflammatory and metabolic markers. Focus groups were undertaken and thematically analyzed to explore participants lived experience of following the diet.

RESULTS

There was no significant change in plasma high-sensitivity C-reactive, protein. Despite discouraging weight loss, median (Q1-Q3) body weight decreased by -0.7 (-1.3 to 0 kg, P = 0.02). This was accompanied by reductions in plasma insulin (0.90 [-0.05 to 2.20] mmol/L), Homeostatic Model Assessment of Insulin Resistance (0.29 [-0.03 to 0.59]), and low-density lipoprotein:high-density lipoprotein ratio (0.18 [-0.01 to 0.40]) ( P ≤ 0.023 for all). Thematic analysis revealed that postmenopausal women have a desire to improve meaningful markers of health status that do not focus on weight. Women were highly engaged with learning about emerging and innovative nutrition topics, favoring a detailed and comprehensive nutrition education style that challenged their proficient health literacy and cooking skills.

CONCLUSIONS

Weight-neutral dietary interventions targeting inflammation can improve metabolic markers and may be a viable strategy for CVD risk reduction in postmenopausal women. To determine effects on inflammatory status, a fully powered and longer-term randomized controlled trial is required.

Weight variability and diabetes complications

Body weight is a recognized risk factor for cardiovascular diseases (CVD). More recently, weight variability, i.e. the oscillation of body weight over time, has also been suggested to be independently associated with development of CVD and mortality in subjects without diabetes and in people with both type 1 and type 2 diabetes (T2D). In T2D, weight variability emerged as one of the most relevant risk factors for CVD and it was suggested to interact with the variability of other risk factors to identify people at high cardiovascular risk. In addition, weight variability seems also to confer a higher risk for microvascular complications in people with T2D. While the exact mechanism linking weight variability to CVD is unknown, evidence from experimental models suggests that weight cycling promote an enduring pro-inflammatory program in the adipose tissue. Here we review the clinical evidence relative to the association of weight variability with CVD and microvascular complications of diabetes. We then briefly summarize the alterations proposed to explain this association. Finally, we synthesize the possible strategies, e.g. specific dietetic regimens and available glucose-lowering drugs, to minimize weight fluctuations.

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.

Baseless Claims and Pseudoscience in Health and Wellness: A Call to Action for the Sports, Exercise, and Nutrition-Science Community

The global health and wellness industry has an estimated value of US$4 trillion. Profits derive from heath club memberships, exercise classes, diets, supplements, alternative 'therapies', and thousands of other products and services that are purported to improve health, recovery, and/or sports performance. The industry has expanded at an alarming rate, far outstripping the capacity of federal bodies to regulate the market and protect consumer interests. As a result, many products are sold on baseless or exaggerated claims, feigned scientific legitimacy, and questionable evidence of safety and efficacy. This article is a consciousness raiser. Herein, the implications of the mismatch between extraordinary health and performance claims and the unextraordinary scientific evidence are discussed. Specifically, we explore how pseudoscience and so-called 'quick fix' interventions undermine initiatives aimed at evoking long-term behavior change, impede the ongoing pursuit of sports performance, and lead to serious downstream consequences for clinical practice. Moreover, pseudoscience in health and wellness, if left unchecked and unchallenged, may have profound implications for the reputation of exercise science as a discipline. This is a call to action to unify exercise scientists around the world to more proactively challenge baseless claims and pseudoscience in the commercial health and wellness industry. Furthermore, we must shoulder the burden of ensuring that the next generation of exercise scientists are sufficiently skilled to distinguish science from pseudoscience, and information from mis- and disinformation. Better population health, sports performance, and the very reputation of the discipline may depend on it.

Intuitive Eating Intervention and Diet Quality in Adults: A Systematic Literature Review

INTRODUCTION

Intuitive eating interventions aim to improve individual health and promote sustainable changes to one's relationship with food. However, there is no evidence-based consensus on the impact of intuitive eating interventions on diet quality. This systematic review aimed to investigate intuitive eating interventions and their impact on diet quality.

METHOD

PubMed, Embase, CINAHL, PsycInfo, and Cochrane databases were systematically searched to October 2021 for studies reporting interventions that encompassed the principles of intuitive eating and measured diet quality. Other health outcomes were used for secondary analysis. Findings were synthesized narratively.

RESULTS

Seventeen papers reporting 14 intervention studies (n = 3,960) were included in the review. All studies found a positive or neutral effect on diet quality following an intuitive eating intervention. A favorable change in eating behavior following these interventions was also observed.

DISCUSSION

Intuitive eating promotes an attunement to the body, which aids in improving diet quality because of increased awareness of physiological cues. The reduction of emotional and binge eating may also increase diet quality.

IMPLICATIONS FOR RESEARCH AND PRACTICE

Findings from the current review suggest that intuitive eating interventions are most effective face-to-face, in a group setting, and sustained for at least 3 months.

BMI variability and incident diabetes mellitus, Tehran Lipid and Glucose Study (TLGS)

Previous epidemiologic studies debated the association of body mass index (BMI) trends with cardiovascular disease and mortality. This study aimed to evaluate the association of BMI variability and slope with the incidence of Type 2 diabetes mellitus (T2DM) in a sex-stratified 15.8-year follow-up in the population-based Tehran Lipid and Glucose Study (TLGS). Of 10,911 individuals aged 20-60 years, 4981 subjects were included and followed for 15.8-years. The slope coefficient of BMI in the linear regression model represented individuals' BMI trends up to the incidence of DM. The root mean squared error (RMSE) of the BMI linear trend was selected to reflect BMI variability through six follow-ups. Cox proportional hazards regression was used to investigate the association of the baseline BMI, BMI slope and RMSE with the incidence of T2DM among men and women. Multivariable-adjusted HRs of T2DM for each SD increment in BMI slope was 1.18 (95% CI: 0.94-1.48, p = 0.161) in normal weight men and 1.26 (95% CI: 1.10-1.44, p = 0.001) in overweight and obese men. However, in women, each SD increment in BMI slope increased the risk of T2DM with a HR of 1.19 (95% CI: 1.01-1.40, p = 0.039) in normal weight, and 1.14 (95% CI: 1.08-1.19, p < 0.001) in women with BMI ≥ 25 kg/m². In men with a baseline BMI ≥ 25 kg/m², BMI-RMSE was associated with a decreased risk of T2DM (HR: 0.71, 95% CI: 0.53-0.93, p = 0.015). Baseline BMI was not associated with the risk of diabetes in men and women. Positive BMI slope is associated with the development of diabetes in both sexes. The association of BMI variability with incident T2DM differs according to sex and baseline BMI. BMI variability is associated with a lower risk of T2DM in overweight and obese men. BMI variability in women and baseline BMI in both gender are not related to the risk of T2DM.

Workplace wellness programs targeting weight outcomes in men: A scoping review

Workplaces have been identified as a priority setting for the delivery of wellness programs to address risk factors for overweight and obesity. Men in particular may benefit greatly from these types of programs as they are typically harder to engage in health promotion. A scoping review was performed to provide an overview of interventions that have been implemented within the workplace that target weight outcomes in men. A searched of six electronic databases (Medline, Embase, CINAHL, Scopus, Cochrane Database of Systematic Review, and Business Source Ultimate) was conducted from January 2010 to August 2020. Of the 2191 articles identified, 25 were included. The majority took place in North America or Europe (72%). Over half (n = 17, 68%) utilized both a nutrition and physical activity component. Thirteen of the 19 articles (68%) that reported weight as an outcome showed the program to be efficacious in reducing weight. Overall, only seven articles were solely focused on an all-male population. Workplace wellness programs targeting weight outcomes in men have been conducted to some extent, with majority being successful in reducing weight. However, there is a need for more randomized controlled trials (RCTs), long-term follow-up, and male-only programs.

Weight cycling in combat sports: revisiting 25 years of scientific evidence

BACKGROUND

As combat sports are classified by body mass, many athletes engage in rapid weight loss (RWL) prior to competition so they can gain an advantage over lighter opponents. Following the weigh-in, athletes engage in rapid weight gain (RWG), whereby some athletes have been able to compete up to three weight categories greater than the official division weighed in at.

RESULTS

Although the impact of weight cycling on performance remains equivocal, robust scientific evidence indicates serious acute and chronic negative consequences on physiological and health-related parameters. Still, weight cycling remains highly prevalent in combat sports, and interventions to limit or stop this cultural norm are recommended.

CONCLUSIONS

Weigh-ins for combat sports should be transitioned to take place closer to the start of competition. This reduced time and access to engage in RWG will cut down, if not completely prevent, weight cycling. These rule changes that aim to benefit athlete's health and promote fairness must be made at the international level, which will promote them at those levels below, as well, given qualification protocols.

Exercising for Insulin Sensitivity - Is There a Mechanistic Relationship With Quantitative Changes in Skeletal Muscle Mass?

Skeletal muscle (SM) tissue has been repetitively shown to play a major role in whole-body glucose homeostasis and overall metabolic health. Hence, SM hypertrophy through resistance training (RT) has been suggested to be favorable to glucose homeostasis in different populations, from young healthy to type 2 diabetic (T2D) individuals. While RT has been shown to contribute to improved metabolic health, including insulin sensitivity surrogates, in multiple studies, a universal understanding of a mechanistic explanation is currently lacking. Furthermore, exercised-improved glucose homeostasis and quantitative changes of SM mass have been hypothesized to be concurrent but not necessarily causally associated. With a straightforward focus on exercise interventions, this narrative review aims to highlight the current level of evidence of the impact of SM hypertrophy on glucose homeostasis, as well various mechanisms that are likely to explain those effects. These mechanistic insights could provide a strengthened rationale for future research assessing alternative RT strategies to the current classical modalities, such as low-load, high repetition RT or high-volume circuit-style RT, in metabolically impaired populations.

Weight Regain and Breast Cancer-Related Biomarkers Following an Exercise Intervention in Postmenopausal Women

BACKGROUND

Epidemiologic studies have reported associations between weight fluctuations and postmenopausal breast cancer risk; however, the biological markers involved in this association are unknown. This study aimed to explore the associations between breast cancer-related biomarkers and weight regain following exercise-induced weight loss.

METHODS

From the 400 participants included in the Breast Cancer and Exercise Trial in Alberta, a total of 214 lost weight during the intervention and had follow-up blood samples, body composition, and covariate measurements. Outcomes were measured at baseline, 12 months (end of the study), and 24 months (follow-up).

RESULTS

During follow-up, weight regain was 1.80 kg [95% confidence interval (CI): -0.40-3.90], and was significantly associated with increases in estradiol [treatment effect ratio (TER) = 1.03; 95% CI, 1.01-1.04], estrone (TER = 1.02; 95% CI, 1.01-1.03), free estradiol (TER = 1.04; 95% CI, 1.02-1.05), the homeostatic model assessment for insulin resistance (TER = 1.03; 95% CI, 1.02-1.05), and insulin (TER = 1.03; 95% CI, 1.01-1.04), and decreases in sex hormone-binding globulin (SHBG; TER = 0.98; 95% CI, 0.97-0.99) levels. Nonstatistically significant associations were found for glucose and C-reactive protein. Furthermore, a statistically significant linear trend of increasing levels for all biomarkers, and decreasing SHBG, across weight regain categories was found.

CONCLUSIONS

These results suggest that weight regain following exercise-induced weight loss is associated with breast cancer-related biomarker changes in postmenopausal women.

IMPACT

These findings provide evidence to support the importance of developing effective strategies to prevent weight regain and, consequently, decrease postmenopausal breast cancer risk via changes in adiposity-related biomarkers.