Diet-Induced Weight Loss Has No Effect on Psychological Stress in Overweight and Obese Adults: A Meta-Analysis of Randomized Controlled Trials

Effects of mental workload on manufacturing systems employees: A mediation causal model

BACKGROUND

Although some research has been done in the Mexican manufacturing industry regarding mental workload, none has explored its association with physical fatigue, body weight gain, and human error simultaneously.

OBJECTIVE

This research examines the association between mental workload and physical fatigue, body weight gain, and human error in employees from the Mexican manufacturing systems through a mediation analysis approach.

METHODS

A survey named Mental Workload Questionnaire was developed by merging the NASA-TLX with a questionnaire containing the mental workload variables mentioned above. The Mental Workload Questionnaire was applied to 167 participants in 63 manufacturing companies. In addition, the mental workload was used as an independent variable, while physical fatigue and body weight gain were mediator variables, and human error was a dependent variable. Six hypotheses were used to measure the relationships among variables and tested using the ordinary least squares regression algorithm.

RESULTS

Findings indicated that mental workload significantly correlates with physical fatigue and human error. Also, the mental workload had a significant total association with human error. The highest direct association with body weight gain was provided by physical fatigue, and body weight gain had an insignificant direct association with human error. Finally, all indirect associations were insignificant.

CONCLUSION

Mental workload directly affects human error, which physical fatigue does not; however, it does affect body weight gain. Managers should reduce their employees' mental workload and physical fatigue to avoid further problems associated with their health.

The effect of cognitive behavioral stress management on perceived stress, biological stress markers and weight loss/regain, from a diet-induced weight loss program: A randomized controlled trial

Obesity and psychosocial stress are inter-related chronic conditions which lead to increased cardiovascular morbidity and mortality. The aim of this parallel randomized controlled trial was to determine whether the addition of a structured cognitive behavioral stress management (CBSM) on to a commercial online weight loss program, resulted in greater weight loss than the standard weight loss program in isolation. Eligible participants were adults between the ages 18-65, BMI 30-45 kg/m2, with no major systemic or psychiatric conditions. Seventy-four participants were assigned according to simple randomization using computer generated random numbers to either a 3-month online Weight Watchers® program (n = 36), or Weight Watchers® plus 10 weekly sessions of CBSM (n = 38). The primary outcome was weight at 3 months compared to baseline. Secondary outcomes were weight at 12 months and subjective/objective stress system measures and metabolic markers at 3 and 12 months. The study was powered at 90% to detect a 5 kg difference in weight between the two groups at 3 months. Independent sample t-tests were used to analyze the difference in weight (in kg) between the groups and paired sample t-tests were used to analyze the difference within group at different time intervals. At follow-up, there was no significant difference in weight loss between the groups (1.8 kg, 2.1 kg). However, CBSM was effective in reducing psychological measures of stress (p < 0.05) and salivary cortisol (waking, 20-min post-waking) at 3-months; with the effect on stress persisting at 12-months within the CBSM group. The reduction in PSS at 3 months was significantly greater in the CBSM group (3.84, p = 0.028) compared to WW only group at 3 months. Addition of CBSM to a standard weight loss intervention did not improve the weight loss over the standard approach on its own, but the CBSM intervention improved psychological stress parameters and cortisol secretion in participants living with obesity.

The impact of adult behavioural weight management interventions on mental health: A systematic review and meta-analysis

There is good evidence that behavioural weight management interventions improve physical health; however, the impact on mental health remains unclear. We evaluated the impact of behavioural weight management interventions on mental health-related outcomes in adults with overweight or obesity at intervention-end and 12 months from baseline. Eligible studies were randomized controlled trials (RCTs) or cluster RCTs of adult behavioural weight loss interventions reporting affect, anxiety, binge eating, body image, depression, emotional eating, quality of life, self-esteem and stress. We searched seven databases from inception to 7 May 2019 and included 43 articles reporting 42 RCTs. Eighteen studies were deemed to be at high risk of bias. We conducted random-effects meta-analyses, stratified analyses and meta-regression using Stata. Interventions generated greater improvements than comparators for depression, mental health-related quality of life and self-efficacy at intervention-end and 12 months from baseline. There was no difference between groups for anxiety, overall quality of life, self-esteem or stress at intervention-end. There was insufficient evidence to assess the impact on anxiety, binge eating, body image, emotional eating, affect, life satisfaction, self-esteem or stress at intervention-end and/or 12 months from baseline. Although evidence suggests that interventions benefit some aspects of mental health, high-quality, transparently reported RCTs measuring a range of mental health outcomes over longer durations are required to strengthen the evidence base.

Effects of a Lifestyle Intervention on Health-Promoting Behavior, Psychological Distress and Reproductive Health of Overweight and Obese Female College Students

This study aimed to examine the effect of a lifestyle intervention (LSI) on overweight or obese female university students. Participants: A total of 53 overweight or obese female college students participated. This study was conducted from May to December 2017 in Jeonbuk Province, South Korea. A quasi-experimental design using a non-equivalent control group pretest-posttest was used. The LSI consisted of providing health information, individual health counseling, lifestyle monitoring, and effective support based on the interaction model of client health behavior, which was implemented for 12 weeks. Significant group differences were found in health-promoting behavior, psychological distress, reproductive health, body weight, body fat, and triglyceride level among participants. LSIs are effective in improving health-promoting behavior, psychological distress, reproductive health, and body composition. Therefore, healthcare providers should develop and apply LSIs through interaction for overweight or obese female college students.

The obesity treatment dilemma: Why dieting is both the answer and the problem? A mechanistic overview

Restricted-calorie diets are the most worldwide used treatments for obesity. Although such strategies are based on the first law of thermodynamics, the real life clinical practice demonstrates that the observed weight losses are divergent from those theoretically predicted. Loosely adherence to recommendations is one of the main causes for the limited efficacy of dieting, but many additional factors can be involved in the hurdles to weight loss. According to the second law of thermodynamics any restriction in dietary energy intake results in energy sparing with a diminution in the basal metabolic rate and a concomitant loss in the lean body mass. This "thrifty" energetic adaptation is associated with a progressive reduction in the difference between levels of energy intake and expenditure, thus resulting in a drastic fall in weight loss rates on the medium and long-term regardless of the dietary carbohydrate/fat ratio. This loss of efficacy is aggravated by the misadaptation of the production and action of anti-obesity hormones such as leptin. During the latest past decades the discovery of changes in the gut microbiota of obese people referred to as "obese dysbiosis" has raised the question as to whether these alterations can participate to diet-resistance. Combined with the behavioral and psychological barriers to low-calorie diets, there is a broad physiologic spectrum of evidence indicating that weight loss is a hard challenge. Consequently, the answer would be primarily to prevent the development of obesity and at worst to avoid its ominous progression from metabolically healthy to unhealthy stages.

Impact of adult weight management interventions on mental health: a systematic review and meta-analysis protocol

INTRODUCTION

The effects of interventions targeting weight loss on physical health are well described, yet the evidence for mental health is less clear. It is essential to better understand the impact of weight management interventions on mental health to optimise care and minimise risk of harm. We will assess the effect of behavioural weight management interventions on mental health in adults with overweight and obesity.

METHODS AND ANALYSIS

The systematic review will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. We will include behavioural weight management interventions with a diet and/or physical activity component focusing on weight loss for adults with a body mass index ≥25 kg/m2. Randomised controlled trials (RCTs) and cluster RCTs will be the only eligible study designs. Outcomes of interest will be related to mental health. The following databases were searched from inception to 07 May 2019: MEDLINE, Embase, Cochrane database (CENTRAL), PsycINFO, ASSIA, AMED and CINAHL. The search strategy was based on four concepts: (1) adults, defined as ≥18 years, with overweight/obesity, defined as BMI ≥25kg/m², (2) weight management interventions, (3) mental health outcomes and (4) study design. The search was restricted to English-language published papers, with no other restrictions applied. Two stage screening for eligibility will be completed by two independent reviewers, with two independent reviewers completing data extraction and risk of bias assessment. Data permitting, a random-effects meta-analysis of outcomes, subgroup analyses and meta-regression will be conducted. If not appropriate, narrative synthesis and 'levels of evidence' assessment will be completed.

ETHICS AND DISSEMINATION

Ethical approval is not required as primary data will not be collected. The completed systematic review will be disseminated in a peer-reviewed journal, at conferences and contribute towards the lead author's PhD thesis.

PROSPERO REGISTRATION NUMBER

CRD42019131659.

Eating behaviors and weight loss outcomes in a 12-month randomized trial of diet and/or exercise intervention in postmenopausal women

Background

Certain eating behaviors are common among women with obesity. Whether these behaviors influence outcomes in weight loss programs, and whether such programs affect eating behaviors, is unclear.

Methods

Our aim was to examine the effect of baseline eating behaviors on intervention adherence and weight among postmenopausal women with overweight or obesity, and to assess intervention effects on eating behaviors.

Four hundred and 39 women (BMI ≥25 kg/m²) were randomized to 12 months of: i) dietary weight loss with a 10% weight loss goal (‘diet’; n = 118); ii) moderate-to-vigorous intensity aerobic exercise for 225 mins/week (‘exercise’; n = 117); iii) combined dietary weight loss and exercise (‘diet + exercise’; n = 117); or iv) no-lifestyle change control (n = 87). At baseline and 12 months, restrained eating, uncontrolled eating, emotional eating and binge eating were measured by questionnaire; weight and body composition were assessed. The mean change in eating behavior scores and weight between baseline and 12 months in the diet, exercise, and diet + exercise arms were each compared to controls using the generalized estimating equation (GEE) modification of linear regression adjusted for age, baseline BMI, and race/ethnicity.

Results

Baseline restrained eating was positively associated with change in total calories and calories from fat during the dietary intervention but not with other measures of adherence. Higher baseline restrained eating was associated with greater 12-month reductions in weight, waist circumference, body fat and lean mass. Women randomized to dietary intervention had significant reductions in binge eating (− 23.7%, p = 0.005 vs. control), uncontrolled eating (− 24.3%, p < 0.001 vs. control), and emotional eating (− 31.7%, p < 0.001 vs. control) scores, and a significant increase in restrained eating (+ 60.6%, p < 0.001 vs. control); women randomized to diet + exercise reported less uncontrolled eating (− 26.0%, p < 0.001 vs. control) and emotional eating (− 22.0%, p = 0.004 vs. control), and increased restrained eating (+ 41.4%, p < 0.001 vs. control). Women randomized to exercise alone had no significant change in eating behavior scores compared to controls.

Conclusions

A dietary weight loss intervention helped women modify eating behaviors. Future research should investigate optimal behavioral weight loss interventions for women with both disordered eating and obesity.

Trial registration

NCT00470119 (https://clinicaltrials.gov). Retrospectively registered May 7, 2007.