BACKGROUND: Obesity may increase surgical complexity in patients undergoing abdominal surgery by limiting visualization and increasing the risk of peri-operative complications. A preoperative reduction in weight and liver volume may improve surgical outcomes. The aim of our study was to evaluate the efficacy of a low-calorie diet (LCD) versus a very low-calorie diet (VLCD) in reducing weight and liver volume prior to laparoscopic surgery.
METHODS: A systematic search was conducted using the following inclusion criteria: obese patients undergoing preoperative weight loss using a VLCD or LCD, evaluation of liver volume reduction, and the use of an imaging modality before and after the diet.
RESULTS: A total of 814 patients from 21 different studies were included in this systematic review and meta-analysis, with 544 female patients (66.8%) and a mean age range between 24 and 54 years old. There was a total mean weight loss of 6.42% and mean liver volume reduction of 16.7%. Meta-analysis demonstrated that a preoperative diet (LCD or VLCD) significantly reduced weight [SMD = - 0.68; 95% CI (- 0.93, - 0.42), I2 = 82%, p ≤ 0.01] and liver volume [SMD = - 2.03; 95% CI (- 4.00, - 0.06), I2 = 94%, p ≤ 0.01]. When assessed individually, a VLCD led to significant weight reduction [SMD = - 0.79; CI (- 1.24; - 0.34), p ≤ 0.01, I2 = 90%], as did an LCD [SMD = - 0.60; CI (- 0.90; - 0.29), p ≤ 0.01, I2 = 68%). Similarly, there was a significant reduction in liver volume following a VLCD [SMD = - 1.40; CI (- 2.77, - 0.03), p ≤ 0.01, I2 = 96%], and an LCD [SMD = - 2.66; CI (- 6.13, 0.81), p ≤ 0.01, I2 = 93%]. However, there was no significant difference between the two regimens.
CONCLUSIONS: Preoperative restrictive calorie diets are effective in reducing weight and liver volume prior to laparoscopic surgery. Whilst a VLCD was better than an LCD at reducing both weight and liver volume, the difference was not significant.

In this editorial, we commented on a recently released manuscript by Zeng et al in the World Journal of Gastroenterology. We focused specifically on lifestyle changes in patients with non-alcoholic fatty liver disease (NAFLD). NAFLD is a hepatic manifestation of the metabolic syndrome, which ultimately leads to advanced hepatic fibrosis, cirrhosis, and hepatocellular carcinoma and affects more than 25% of the population globally. Existing therapeutic strategies against NAFLD such as pharmacologic therapies focus on liver protection, anti-inflammation, and regulating disease-related metabolic disorder symptoms. Although several drugs are in late-stage development, potent drugs against the diseases are lacking. Additionally, existing surgical approaches such as bariatric surgery are not routinely used to treat NAFLD. Intervening in patients\' unhealthy lifestyles, such as weight loss through dietary changes and exercises to ameliorate patient-associated metabolic disorders and metabolic syndrome, is the first-line treatment for patients with NAFLD. With sufficient intrinsic motivation and adherence, the management of unhealthy lifestyles can reduce the severity of the disease, improve the quality of life, and increase the survival expectancy of patients with NAFLD.

Estimating the change rates in body size following the weight loss programs is very important in the compliance of those programs. Although, there is enough evidence on the significant association of body weight change with the other anthropometric indices and/ or body composition, there is so limited studies that have depicted this relationship as mathematical formulas. Therefore, the present research designed to use a mathematical model to predict changes of anthropometric indices following a weight-loss diet in the overweight and obese women. In this longitudinal study, 212 overweight/obese women who received an individualized low-calorie diet (LCD) were selected and followed-up for five months. Anthropometric measurements such as weight, waist circumference (WC), hip circumference (HC), and body composition (lean mass and fat mass) were performed. Then, body mass index, waist to hip ratio (WHR), waist to height ratio (WHtR), a body shape index (ABSI), abdominal volume index (AVI), and body adiposity index (BAI) were calculated using the related formula. Following the LCD led to the substantial and consistent changes in various anthropometric indices over time. All of these anthropometric variations were significantly related with the percent change (PC) of body weight except than WHR. Moreover, according to the mathematical formulas, weight loss was closely related to the decrease of WC (PC-WC =  - 0.120 + 0.703 × PC-WT), HC (PC-HC =  - 0.350 + 0.510 × PC-WT), body fat percentage (PC-Body Fat =  - 0.019 + 0.915 × PC-WT), WHtR (PC-WHtR =  - 0.113 + 0.702 × PC-WT), and improvements in ABSI (PC-ABSI =  - 0.112 + 0.034 × PC-WT) and AVI (PC-AVI =  - 0.324 + 1.320 × PC-WT). The decreasing rates of WC, HC, body fat percentage, WHtR, ABSI, and AVI in relation to the weight loss were clinically and statistically significant. This means that a healthy weight lowering diet would be accompanied by decreasing the body fat, body size and also the risk of morbidities.

Weight regain subsequent to weight reduction resulting from dietary interventions represents a prevalent phenomenon recognized as \"Yo-yo dieting.\" However, the impact of prolonged Yo-yo dieting on health, especially in relation to the aging process, remains poorly understood. This study aimed to investigate the influence of Yo-yo dieting on the aging process in male Drosophila melanogaster that have been exposed to a high-calorie (HC) diet. Fruit flies were fed with either a consistent HC diet or an alternating regimen of HC and low-calorie diets every 3 days (referred to as \"Yo-yo dieting\") for a total of 24 days. Biochemical assays were utilized to quantify levels of oxidative stress and activities of the mitochondrial respiratory chain complexes. The frozen section staining method was employed to assess the presence of lipid droplets, reactive oxygen species, cellular viability, and mitochondrial abundance in tissues. Additionally, we examined the expression of key regulators involved in mitochondrial dynamics and biogenic signaling pathways. Yo-yo dieting resulted in an extension of the fruit flies\' lifespan, concomitant with reduced body weight, decreased body protein content, and lower triglyceride levels compared to continuous a HC diet feeding. Furthermore, Yo-yo dieting ameliorated impairments in motility and intestinal barrier function. Importantly, it improved mitochondrial function and upregulated the expression of essential mitochondrial fusion proteins, namely mitofusin 1 and mitofusin 2, optic atrophy 1, and peroxisome proliferator-activated receptor-γ coactivator-1α. Therefore, the practice of Yo-yo dieting extends the lifespan of fruit flies by modulating mitochondrial dynamics and the associated biogenic signaling pathways.

BACKGROUND: Individuals with overweight or obesity are at a high risk for so-called \'atypical\' or immunometabolic depression, with associated neurovegetative symptoms including overeating, fatigue, weight gain, and a poor metabolic profile evidenced e.g. by dyslipidemia or hyperglycemia. Research has generated preliminary evidence for a low-calorie diet (LCD) in reducing depressive symptoms. The aim of the current systematic review and meta-analysis is to examine this evidence to determine whether a LCD reduces depressive symptoms in people with overweight or obesity.
METHODS: Eligible studies were identified through PubMed, ISI Web of Science, and PsycINFO until August 2023. Standardized mean differences (SMDs) were derived using random-effects meta-analyses for (1) pre-post LCD comparisons of depression outcomes, and (2) LCD v. no-diet-control group comparisons of depression outcomes.
RESULTS: A total of 25 studies were included in the pre-post meta-analysis, finding that depression scores were significantly lower following a LCD (SMD = -0.47), which was not significantly moderated by the addition of exercise or behavioral therapy as a non-diet adjunct. Meta-regressions indicated that a higher baseline BMI and greater weight reduction were associated with a greater reduction in depression scores. The intervention-control meta-analysis (n = 4) found that overweight or obese participants adhering to a LCD showed a nominally lower depression score compared with those given no intervention (SMD = -0.29).
CONCLUSIONS: There is evidence that LCDs may reduce depressive symptoms in people with overweight or obesity in the short term. Future well-controlled intervention studies, including a non-active control group, and longer-term follow-ups, are warranted in order to make more definitive conclusions.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a common liver disease characterized by an increase in fat in liver cells. The outbreak of NAFLD is estimated to be 32.4% worldwide, with higher rates in Asia and Iran. Nutritional factors such as excessive calorie intake, high fructose intake, copper deficiency, and increased iron intake play an important role in NAFLD. Since there is no specific treatment for NAFLD, intermittent fasting (IF) diet has been suggested as an alternative treatment for obesity and related complications. Previous studies showed the potential positive effects of IF on metabolic health and the reduction of oxidative stress in NAFLD. This randomized controlled trial (RCT) will be aimed to examine the effect of the IF diet in comparison with a low-calorie diet (LCD) on lipid profile, glycemic status, and liver fibrosis in patients with NAFLD.
METHODS: This is a parallel randomized clinical trial conducted on 52 overweight and obese patients with NAFLD. Participants will be randomly assigned to receive either 16:8 IF (fasting from 8 P.M. to 12 P.M. the next day) or a low-calorie (55% carbohydrate- 30% fat, 15% protein) diet for 12 weeks. Anthropometric measurements, liver assessments, and metabolic evaluations will be assessed before and after the intervention. Primary outcomes include liver steatosis and fibrosis, while secondary outcomes include liver function enzymes, insulin resistance, lipid profile, and anthropometric measurements.
CONCLUSIONS: Since obesity and insulin resistance are the most important risk factors of NAFLD, and there is no treatment for it, it seems that lifestyle changes such as low caloric diet like IF and exercise can improve lipid metabolism and liver enzymes.
BACKGROUND: Iranian registry of clinical trials (IRCT20170202032367N5).

BACKGROUND: Previous research has illustrated a drift in the fidelity of behaviour change techniques (BCTs) during the design of the pilot NHS England Low-Calorie Diet (NHS-LCD) Programme. This study evaluated a subsequent domain of fidelity, intervention delivery. Two research questions were addressed: (1) To what extent were BCTs delivered with fidelity to providers programme plans? (2) What were the observed barriers and facilitators to delivery?
METHODS: A mixed-methods sequential explanatory design was employed. Remote delivery of one-to-one and group-based programmes were observed. A BCT checklist was developed using the BCT Taxonomy v1; BCTs were coded as present, partially delivered, or absent during live sessions. Relational content analysis of field notes identified observed barriers and facilitators to fidelity.
RESULTS: Observations of 122 sessions across eight samples and two service providers were completed. Delivery of the complete NHS-LCD was observed for five samples. Fidelity ranged from 33% to 70% across samples and was higher for group-based delivery models (64%) compared with one-to-one models (46%). Barriers and facilitators included alignment with the programme\'s target behaviours and outcomes, session content, time availability and management, group-based remote delivery, and deviation from the session plan.
CONCLUSIONS: Overall, BCTs were delivered with low-to-moderate fidelity. Findings indicate a dilution in fidelity during the delivery of the NHS-LCD and variation in the fidelity of programmes delivered across England. Staff training could provide opportunities to practice the delivery of BCTs. Programme-level changes such as structured activities supported by participant materials and with sufficient allocated time, might improve the delivery of BCTs targeting self-regulation.

BACKGROUND: Low-calorie diets, high in protein and low in carbohydrates, are commonly recommended for patients with pre-diabetes and type 2 diabetes. The objective of this study was to carry out a cost-benefit analysis (CBA) of a low-calorie versus a standard diet from the perspective of the Saudi Arabian health system.
METHODS: The CBA compares costs and benefits of the two diet strategies over a 1-year time horizon. Costs included diet and diabetes treatment-related resources while benefits were measured in terms of the costs of diabetes complications avoided. Data on costs and benefits were collected from published literature and subject matter experts. Incremental costs were estimated as the cost difference between low-calorie and standard diet. Incremental benefits were estimated as cost difference from medical complications when following a low-calorie or standard diet. The incremental absolute cost-benefit ratio was calculated to show the difference between the costs and benefits of the low-calorie diet. Incremental relative cost-benefit ratio was calculated to show the cost per dollar of benefit obtained. Monte Carlo simulation modeled variability in outcomes due to variation in costs and uncertainty of diabetes complications.
RESULTS: The 1 year cost of standard diet was US$2515 ± 156 compared to US$2469 ± 107 per patient for a low-calorie diet. Incremental benefit is estimated at US$21,438 ± 7367 per patient. The estimated incremental absolute cost-benefit ratio was US$ - 21,360 establishing that benefits are greater than costs, while the estimated incremental relative cost-benefit ratio is 0.0037, establishing that benefits are 270 times greater than costs.
CONCLUSIONS: The low-calorie diet was the dominant strategy compared to the standard diet in modeled scenarios. These findings highlight the importance of a low-calorie diet as part of diabetes management programs for outpatients with type 2 diabetes.

UNASSIGNED: The last decade has seen the increased prevalence of obesity as a public health challenge, particularly in low- and middle-income countries. At the same time, studies have shown that there is a two-way relationship between low-calorie diets and depression in obese individuals. This study was designed and implemented to investigate the effect of a low-calorie high-protein diet on psychometric variables in obese individuals.
UNASSIGNED: The present study is a Randomized Clinical Trial. Individuals meeting the inclusion criteria were randomly assigned to either the intervention group (low-calorie diet with increased protein percentage) or the control group (standard protein percentage) using block stratification. Psychometric characteristics of the participants were evaluated using the DASS-21 questionnaire.
UNASSIGNED: There were no significant differences in enrollment between the two groups with respect to anthropometric variables, body composition, and physical activity (p-value > .05). Similarly, no significant differences were observed between the two groups in terms of psychological variables (depression, anxiety and stress) (p-value > .05). However, the intervention groups had significantly lower depression and anxiety scores 15 days into the intervention (p-value < .05). After 30 and 60 days of intervention, significant differences were observed between the 2 groups in terms of depression, stress, and anxiety (p-value < .05), indicating a relative improvement in psychometric variables in the intervention group (p-value < .05).
UNASSIGNED: The results of this study showed that low-calorie diets with a high-protein percentage can significantly improve psychometric variables in obese people.Trial registration: Iranian Registry of Clinical Trials identifier: IRCT20221101056371N1..

UNASSIGNED: Chronic-plaque psoriasis is a chronic inflammatory dermatological disease. Obesity comorbidities, including non-alcoholic fatty liver disease, are highly prevalent in patients with chronic-plaque psoriasis. Recently, weight loss has been a highly recommended intervention to improve the severity of psoriatic symptoms, psoriasis-induced chronic systemic inflammation, psoriasis-associated cardiovascular risk factors, quality of life, and the efficacy of anti-psoriatic drugs. This study was designed to assess the effect of a 12-week low-calorie-diet intervention on aspartate transaminase, psoriasis severity (assessed via Psoriasis Area and Severity Index - PASI), alanine transaminase, quality of life (assessed via Dermatology Life Quality Index - DLQI), triglycerides, waist circumference (WC), and body mass index (BMI) in class I obese men with chronic-plaque and non-alcoholic fatty liver disease.
UNASSIGNED: Sixty men with age ≥ 18 years with class I obesity and with chronic plaque psoriasis and non-alcoholic fatty liver disease were included in the study. All participants were randomly assigned to one of two groups: the first group as the low-calorie-diet group (30 men received immunosuppressive drugs, followed a low-calorie diet, and increased their energy expenditure through a daily 15,000-step outdoor walking program for 12 weeks) and the second as the control group (30 men received immunosuppressive drugs only). The primary outcome consisted of the results of the area and severity index. Weight, BMI, WC, laboratory results such as triglycerides, liver enzymes (alanine transaminase and aspartate transaminase) as well as DLQI were considered as secondary outcomes.
UNASSIGNED: While no significant improvements were achieved in the measured variables of the control group, the low-calorie-diet group demonstrated significant improvement in all the measured variables.
UNASSIGNED: The results of the present study confirmed that 12-week low-calorie-diet intervention controls BMI, increases the response of psoriasis to pharmacological agents and improves the quality of life. Diet interventions significantly control the elevated hepatic enzymes (aspartate and alanine transaminases) and triglycerides in male patients with chronic-plaque psoriasis and non-alcoholic fatty liver disease.