Low-calorie Diet Research Articles

The role of bariatric surgery in the treatment of urinary incontinence in obese women

Obesity has become an epidemic in recent decades, affecting millions of people worldwide. Many studies proved a cause between obesity and urinary incontinence in women. Lifestyle modifications, low-calorie diet, and weight loss surgery can improve symptoms of urinary incontinence in obese patients. Studying the effect of bariatric surgery on urinary incontinence symptoms has shown positive results in the short term period. However, there is data on worsening due to regaining weight in the long term period. Contradictory study search findings emphasize the need for further research and development of new clinical recommendations for effective treatment of urinary incontinence in women with obesity.

Effects of different types of intermittent fasting on metabolic outcomes: an umbrella review and network meta-analysis.

Intermittent fasting (IF) holds promise for enhancing metabolic health. However, the optimum IF forms and their superiority over continuous energy restriction (CER) remain unclear due to disconnected findings. We systematically searched PubMed, Embase, and the Cochrane databases for meta-analyses of randomized controlled trials (RCTs) investigating the association between IF and metabolic health outcomes. Subsequently, we performed an umbrella review and network meta-analysis (NMA) to evaluate the efficacy of different forms of IF (time-restricted eating (TRE), alternate-day fasting (ADF), and 5:2 diet (regular eating for 5days and energy restriction for 2days per week)) compared to CER and usual diets on metabolic health outcomes. To assess the certainty of both direct and indirect estimates, we employed the Confidence in Network Meta-Analysis (CINeMA) approach. Additionally, we calculated the surface under the cumulative ranking curve (SUCRA) for each dietary strategy to determine their ranking in terms of metabolic health benefits. Ten of the best and non-redundant meta-analysis studies, involving 153 original studies and 9846 participants, were included. When considering direct evidence only, all IF forms significantly reduced body weight compared to usual diets. In NMAincorporating indirect evidence, all IF regimens alsosignificantly reduced body weight compared to usual diets. In the SUCRA of NMA, IF ranked higher than usual diets or CER in 85.4% and 56.1% of the outcomes, respectively. ADF had the highest overall ranking for improving metabolic health (ranked first: 64.3%, ranked second: 14.3%). Overall, all IF forms demonstrate potentials to improve metabolic health, with ADF appearing to produce better outcomes across investigated outcomes. Further high-quality trials are warranted to confirm the (relative) efficacy of IF on metabolic health. PROSPERO (record no: CRD42022302690).

A Very Low-Calorie Ketogenic Diet Approach for Post-Bariatric Weight Regain: A Pilot Study

Weight regain (WR) after bariatric surgery, particularly sleeve gastrectomy, is a significant challenge, often driven by a combination of metabolic, behavioral, and lifestyle factors. Non-surgical interventions to manage WR are critical, given the increased risks and reduced efficacy of revisional surgeries. In this context, very low-calorie ketogenic diets (VLCKDs) have gained attention for their potential to promote weight loss and improve body composition in individuals struggling with WR. This study assessed the safety and efficacy of a VLCKD in 11 patients who experienced WR following sleeve gastrectomy. Over an 8-week period, patients demonstrated a significant average weight loss of 6.3% (p = 0.005), along with improvements in body composition, including reductions in body fat percentage (p = 0.003) and waist circumference (p = 0.003). Metabolic markers, such as insulin resistance (HOMA-IR), also improved significantly (p = 0.041). Although a decrease in the glomerular filtration rate was observed (p = 0.007), this finding is unlikely to be clinically relevant over the short term. Importantly, no major adverse events were reported, with only mild constipation observed. These results suggest that VLCKDs may be a promising non-surgical approach for managing WR post-bariatric surgery, though further studies are needed to assess long-term effects, especially on renal function.

Weight Loss Induces Changes in Vitamin D Status in Women with Obesity but not in Men: a Randomized Clinical Trial.

Obesity is associated with low vitamin D and recent studies have suggested a difference in vitamin D metabolism between females and males. The aim of this study was to investigate the effects of weight loss on vitamin D status in individuals with obesity, and secondarily, whether vitamin D metabolism differs between women and men. Secondary analysis from a randomized placebo-controlled trial, designed to investigate the efficacy of 52 weeks of treatment with either liraglutide, exercise or combined, compared with placebo on weight loss maintenance after an 8-week low-calorie diet-induced weight loss in 195 individuals with obesity (BMI 32-43 kg/m2). The low-calorie diet-induced weight loss resulted in an increase in serum 25(OH)D in both women and men (12 nmol/L (95%CI 9-15) and 13 nmol/L (95%CI 8-17); p < 0.001 for both). Women who experienced a further weight loss during the 52 weeks of intervention had an increase in serum 25(OH)D compared with women regaining weight (14 nmol/L (95%CI 6-22); p = 0.001). Interestingly, women experiencing further weight loss at week 52 had a lower serum 25(OH)D at baseline compared with women regaining weight (54 nmol/L (SD 19) vs. 70 nmol/L (SD 25); p < 0.001). Weight loss induced by a low-calorie diet resulted in an increase in serum 25(OH)D in both women and men. Only in women, further weight loss had an additional beneficial impact on vitamin D. Additionally, initial low serum 25(OH)D was associated with successful weight loss maintenance in women, but not men.

Short-term intermittent fasting and energy restriction do not impair rates of muscle protein synthesis: A randomised, controlled dietary intervention

BackgroundIntermittent fasting (IF) is an effective energy restricted dietary strategy to reduce body and fat mass and improve metabolic health in individuals with either an overweight or obese status. However, dietary energy restriction may impair muscle protein synthesis (MPS) resulting in a concomitant decline in lean body mass. Due to periods of prolonged fasting combined with irregular meal intake, we hypothesised that IF would reduce rates of MPS compared to an energy balanced diet with regular meal patterns. AimsWe assessed the impact of a short-term (ten days) alternate day fasting or a continuous energy restricted diet to a control diet on integrated rates of skeletal MPS in middle-aged males with overweight or obesity. MethodsTwenty-seven middle-aged males with overweight or obesity (age: 44.6±5.4 y; BMI: 30.3±2.6 kg/m2) consumed a three-day lead-in diet, followed by a ten-day controlled dietary intervention matched for protein intake, as alternate day fasting (ADF: 62.5 energy (En)%, days of 25 En% alternated with days of 100 En% food ingestion), continuous energy restriction (CER: 62.5 En%), or an energy balanced, control diet (CON: 100 En%). Deuterated water (D2O) methodology with saliva, blood, and skeletal muscle sampling were used to assess integrated rates of MPS over the ten-day intervention period. Secondary measures included fasting plasma glucose, insulin, and gastrointestinal hormone concentrations, continuous glucose monitoring, and assessment of body composition. ResultsThere were no differences in daily rates of MPS between groups (ADF: 1.18±0.13, CER: 1.13±0.16, and CON: 1.18±0.18%/day, P>0.05). The reductions in body mass were greater in ADF and CER compared to CON (P<0.001). Lean and fat mass were decreased by a similar magnitude across groups (main time effect, P<0.001; main group effect, P>0.05). Fasting plasma leptin concentrations decreased in ADF and CER (P<0.001), with no differences in fasting plasma glucose or insulin concentrations between groups. ConclusionShort-term alternate day fasting does not lower rates of MPS compared to continuous energy restriction or an energy balanced, control diet with matched protein intake. The prolonged effects of IF and periods of irregular energy and protein intake patterns on muscle mass maintenance remain to be investigated. This trial was registered under Australian New Zealand Clinical Trial Registry (https://www.anzctr.org.au), identifier no. ACTRN12619000757112.

Using stereotype violation to shift causal understanding and attitudes about weight

ObjectiveWe evaluated an approach to weight stigma reduction involving the provision of an exemplar inconsistent with belief systems underlying weight bias. Specifically, that people with higher weight eat unhealthy, high-calorie diets, and people with lower weight eat healthy, low-calorie diets. Providing exemplars that violate the stereotype's assumptions may lead to a change in beliefs, stereotypes, and ultimately, stigma. MethodsIn an experimental, web-based study, 682 US-based participants were randomized to read narrative vignettes about a fictional middle-aged woman portrayed as either having stable, high body weight, or stable, low body weight, and as eating a long-term diet that was either high- or low- in calorie-dense foods. Two stereotype violation conditions involved a woman with higher weight who maintains a low-calorie diet (HWLC) and a woman with lower weight who maintains a high-calorie diet (LWHC). ResultsFor the HWLC exemplar, results were consistent with stereotype change processes including heightened genetic causal attributions, reduced lifestyle attributions, and more positive attitudes toward the exemplar and “women with obesity” in general. Response to the LWHC exemplar was more uneven. ConclusionsFindings have implications in the understanding of judgments that people make about individuals based on their body size, and dietary habits suggest a new route for interventions that address weight stigma reduction.

The Relationship Between Dance Training Volume, Body Composition, and Habitual Diet in Female Collegiate Dancers: The Intercollegiate Artistic Athlete Research Assessment (TIAARA) Study.

This study's purpose was to evaluate the relationship between dance training volume, body composition, and habitual diet in female collegiate dancers. Thirty-three female collegiate dancers from three dance programs (20.4 ± 1.05 yrs.; 165.4 ± 11.3 cm, BMI 21.3 ± 3.4 kg/m2) participated in "The Intercollegiate Artistic Athlete Research Assessment (TIAARA)" study. We assessed dance training volume, body composition, and habitual diet. Data were analyzed using descriptive statistics (means ± SD). Two-sample t-tests were conducted to compare reported intake values versus sports nutrition recommendations. Two-tailed Pearson correlations (r) were computed for body composition and dietary intake (p < 0.05). Collegiate dancers were enrolled in 16 ± 2.09 semester credits, with 7.7 ± 3.8 credits as dance movement courses and an additional 3.0 ± 1.5 h/week of rehearsal time. Body composition assessments included fat mass (24.4 ± 6.8%), lean mass (LM) (42.4 ± 10.1 kg), and total body water (32.6 ± 4.6 L). Habitual diets reflected a low-calorie diet (1399 ± 648 kcal/d), with ~20% of dancers consuming a very low-calorie diet (≤1000 kcal/d). Dancers reported under-consuming dietary protein (54.3 ± 26.2 g) and carbohydrate (171.8 ± 77.8 g). LM was positively correlated with daily total energy (r = 0.333), fat (r = 0.37), protein (r = 0.349), and leucine intake (r = 0.352). Our findings emphasize the positive effect of adequate nutritional quantity and quality on body composition in female collegiate dancers.

Energy expenditure, metabolic adaptation, physical activity and energy intake following weight loss: comparison between bariatric surgery and low-calorie diet.

Bariatric surgery remains the most effective treatment to achieve substantial weight loss; however, total daily energy expenditure and physical activity changes in response to such interventions have been seldom explored. In this prospective observational study, total daily energy expenditure (TDEE) using doubly labeled water and physical activity (SenseWear armband) was assessed in 17 females (mean ± SD: 48.6 ± 9.7 kg/m2, 43 ± 12 years) at baseline and 8 and 52 weeks following either bariatric surgery (BSG, N = 9) or a low-calorie diet (LCD, N = 8). Energy intake was assessed using the intake-balance method. After 8 weeks, weight loss was 16.0 ± 3.5 kg and TDEE decreased by 552 ± 319 kcal/d in BSG (P < 0.001) compared to 8.8 ± 3.4 kg and 256 ± 239 kcal/d in LCD (P < 0.05). After 52 weeks, weight loss was 44.3 ± 16.4 kg and TDEE decreased by 583 ± 418 kcal/d (P < 0.001), compared to 4.3 ± 6.7 kg and 84 ± 285 kcal/d in LCD (P > 0.05). TDEE was lower than predicted in BSG at 8 (P = 0.03) but not 52 weeks (P = 0.77). There was no evidence of metabolic adaptation in LCD. Average daily energy intake in BSG was 1403 ± 245 kcal/d compared to 2545 ± 398 kcal/d in LCD (P < 0.001). In BSG, step count and physical activity minutes were increased at 52 weeks compared to baseline (P = 0.03), whereas no significant changes were observed in LCD. Bariatric surgery-induced weight loss decreased TDEE at 8 weeks and 1 year, resulting in metabolic adaptation after 8 weeks that was reversed at 1 year. These changes were accompanied by an increase in physical activity.

Dynamics of the human bile acid metabolome during weight loss

Bile acids (BA) are supposed to cause metabolic alterations after bariatric surgery (BS). Here we report the longitudinal dynamics of the human BA metabolome by LC–MS/MS after BS versus low calory diet (LCD) in two obesity cohorts over 12 months. Rapid and persistent oscillations of 23 BA subspecies could be identified with highly specific patterns in BS vs. LCD. TCDCA, GLCA, and TLCA represent most promising candidates for drug development.

The safety, tolerability and clinical impact of pre-operative very low-calorie diet prior to non-bariatric abdominal surgery: a systematic review

The safety, tolerability and clinical impact of pre-operative very low-calorie diet prior to non-bariatric abdominal surgery: a systematic review

Reducing the climate impact of food choices with comparable nutritional quality: a randomised trial

Abstract Background Diets largely contribute to the global disease burden, and a third of global warming emissions. We assessed the climate footprint reduction effect of framing the climate impact of diets as a collective action problem (social dilemma), compared or in combination with a reflective intervention (information) and a choice architecture intervention (nudge). Interactions with lifestyle factors were examined. Methods A randomised 2X2X2 between-subjects online experiment was conducted among university students ≥18 years, enrolled at a Swiss university, and not following a medically prescribed diet. The outcome was the mean climate footprint of food choices (in kg CO2-eq), based on a Life Cycle Assessment. Meals varied in climate footprints while adhering to the Swiss dietary guidelines. Results This analysis focused on the subset of meat eaters (n = 1691). Median age was 24 years, and 59.85% (n = 1012) were female. Seven intervention groups resulted in significantly lower climate footprints compared to the control. The social dilemma plus a nudge menu was the most effective behavioural intervention leading to 20.20% footprint reduction (b = -1.20 kg CO2-eq) compared to the control group (Mcontrol=5.94, SDcontrol=2.76; Mdilemma+nudge=4.74, SDdilemma+nudge=2.09 t(436) = -5.10, p &amp;lt; 0.001). Lifestyle factors linked to a higher climate footprint of food choices included adhering to a low-calorie diet (b = 1.21 kg CO2-eq, p &amp;lt; 0.05), or a muscle gain diet (b = 2.12 kg CO2-eq p &amp;lt; 0.05) and practising physical activities (PA) while adhering to a muscle-gain diet (Aerobic/Cardio: 3.82 kg CO2-eq, p &amp;lt; 0.05; Muscle-strengthening: 2.24 kg CO2-eq, p &amp;lt; 0.05). Conclusions The combination of reflective collective action communication and menu nudges is an effective strategy to mitigate the climate footprint of food choices in education institutions. Adherence to a muscle-gain diet was identified as a critical but manageable lifestyle factor linked to a higher climate footprint. Key messages • The dilemma plus a nudge was the most effective to reduce the climate footprint of food choices. • This combined intervention can manage the high climate footprints linked to lifestyle factors.

The impact of 3 different dietary interventions on overweight or obese adults: A network meta-analysis.

This network meta-analysis aims to investigate and compare the effectiveness of 3 dietary interventions - Mediterranean, ketogenic, and low-fat diet - on overweight and obese adults, with a comparison to traditional low-calorie diet. A systematic review was conducted in both Chinese and English databases, including the China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), SinoMed, PubMed, Web of Science, Cochrane Library and Embase to identify relevant randomized controlled trials (RCTs) up to January 31, 2024. Two researchers independently screened and extracted data from the identified literature. The quality of these studies was assessed using the Cochrane bias risk assessment tool. A random-effects network meta-analysis was performed using Review Manager 5.4.1 and Stata 16.0 software. A total of 17 randomized controlled trials involving 5802 subjects were included in this study. The network meta-analysis revealed a descending order of effectiveness for reducing body weight (BW), body mass index (BMI), and waist circumference (WC): ketogenic diet > low-fat diet > low-calorie diet > Mediterranean diet. The ketogenic diet was identified as the most effective intervention for reducing BW, BMI, and WC in the studied dietary comparisons. It consistently showed superior outcomes, ranking highest in effectiveness among the 4 evaluated dietary approaches. Nevertheless, additional high-quality randomized controlled trials are necessary to validate these findings.

Low-calorie, high-protein diets, regardless of protein source, improve glucose metabolism and cardiometabolic profiles in subjects with prediabetes or type 2 diabetes and overweight or obesity.

The aim was to study the effect of two low-calorie, high-protein (HP) diets, with most of the protein coming from animal or plant sources, on glycaemic and other cardiometabolic outcomes in subjects with overweight or obesity and glucose metabolism disorders. A total of 117 participants aged >18 years with body mass index over 27.5 kg/m2 and prediabetes or type 2 diabetes mellitus (T2DM) were randomized to one of two HP low-calorie diets (35% of total calories from protein), in which 75% of the protein was from either plant-based sources (HPP) or animal sources (HPA). For both diets, 30% and 35% of the total calories were from fat and carbohydrates, respectively. The dietary intervention lasted 6 months. Both diets improved body composition to a similar extent, including weight loss (-8.05 ± 5.12 kg for the HPA diet and -7.70 ± 5.47 kg for the HPP diet at 6 months) and fat mass, mainly visceral fat. Both diets had a similar beneficial effect on glucose metabolism, including fasting glucose, insulin, homeostasis model assessment of insulin resistance index and glycated haemoglobin. Other biochemical parameters, including lipid profiles, liver enzymes, adipokines and inflammatory biomarkers, similarly improved in both groups. Fasting incretins, mainly glucagon-like peptide 1, decreased significantly in both groups, and this effect correlated with weight loss. Low-calorie HP diets improved body composition, glucose metabolism and other cardiometabolic outcomes, regardless of protein source (either animal or plant sources), in outpatients with prediabetes or T2DM. The clinical trial was registered in ClinicalTrials.gov (identifier: NCT05456347) https://clinicaltrials.gov/study/NCT05456347?term=NCT05456347&rank=1.

Reduction of the risk of biliary lithiasis caused by various weight reduction options in obesity

At present obesity is a major public health challenge globally, which accounts for a significant portion of all healthcare costs. Obesity and its complications, insulin resistance and dyslipidemia, have been identified as independent risk factors for cholelithiasis. Cholelithiasis is mainly caused by four factors: bile cholesterol overload caused by excess cholesterol made in the liver due to genetic factors; systolic dysfunction of the gallbladder wall; bowel dysfunction with excess absorption of cholesterol or cholesterol overload caused by impaired hepatic bile circulation; and accelerated growth of cholesterol crystals and solid cholesterol crystals. Rapid weight loss (≥1.5 kg/week) due to low-calorie diets as the main treatment method, or after bariatric surgery is one of the risk factors for gallstone formation. Bariatric surgery is effective for the treatment of obesity and its complications, but bariatric surgery does not reduce the incidence of cholelithiasis. On the contrary, many studies showed that bariatric surgery may increase the incidence of cholelithiasis. The rapid weight loss causes fat mobilization and then increases serum cholesterol and triglyceride levels. On the other hand, bowel dysfunction due to bariatric surgery is accompanied by decreased cholecystokinin levels, causing impaired gallbladder contractility. Cholelithiasis requires close attention after bariatric surgery, with 10% of patients undergoing bariatric surgery having to undergo cholecystectomy postoperatively due to a high risk of cholelithiasis. UDCA is a natural bile acid that is prescribed to be taken orally (by mouth). UDCA inhibits the absorption of cholesterol in the bowel, enhances the biosynthesis of bile acids, and reduces biliary cholesterol secretion. UDCA is a choleretic agent, as all bile acids, but differs from other dihydroxy bile acids in being non-cytotoxic. The use of UDCA while following a low-calorie diet and after bariatric surgery significantly reduces the risk of gallstone formation and cholecystectomy with associated complications.

Dietary recommendations for bariatric patients

Over the past few decades, obesity has become a growing public health problem worldwide. The goal of fighting obesity is to improve health. Sustained weight loss of more than 10% of the total body weight improves the course of many obesity-related diseases, as well as the quality of life. The high effectiveness of bariatric surgery in the treatment of obesity in achieving significant and sustained weight loss has been demonstrated in several studies. In most centers where bariatric surgery is performed, the recommendation for preoperative weight loss is followed. The enlarged left lobe of the liver makes it difficult to access the stomach and, accordingly, prevents technically correct operation. Weight loss before bariatric surgery reduces the risk of complications in the postoperative period, and therefore preoperative preparation in the form of hypocaloric nutrition and regular physical activity is recommended for patients, considering concomitant pathology. One of the problems in the postoperative period is the need to change the usual lifestyle and diet due to the need to follow the recommendations of the attending physician. This can lead to a decrease in the quality of life after surgery due to psychoemotional overstrain. The nutrition of bariatric patients implies significant changes associated with a decrease in the amount of food consumed, difficulty in assimilation of nutrients, and the poverty of flavors offered up to this day in the specialized nutrition market. With the help of food products within the framework of low-calorie diets, it becomes almost impossible to feed such a patient without reducing their nutritional value. In 2024, balanced low-calorie nutrition OPTIFAST® (OPTIFAST) appeared on the Russian market, which has proven itself worldwide for more than 50 years and has shown its effectiveness and safety in more than 80 international clinical trials with a high level of evidence. OPTIFAST provides the patient with all the necessary nutrients and allows you to manage the daily calorie intake, gives the patient a feeling of satiety necessary for high adherence to a low-calorie diet, which is indicated for patients with obesity and overweight.

The effect of MIND diet on sleep status, anxiety, depression, and cardiometabolic indices in obese diabetic women with insomnia: study protocol for a randomized controlled clinical trial {1}

BackgroundThe Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet is a plant-based and anti-inflammatory diet that has the ability to protect and manage cardiovascular and nervous system diseases. Regarding that insomnia and cardiovascular problems are x`common in type 2 diabetes mellitus (T2DM), the present study will assess the effectiveness of the MIND dietary pattern on sleep quality, cardiometabolic indicators, and other psychological indicators.MethodsForty-four overweight/obese T2DM women with insomnia, aged 30–65 years, will voluntarily participate in this randomized controlled trial and will be randomized to receive either a MIND low-calorie diet (MLCD) or a low-calorie diet (LCD) over a 3-month period. Before and after the study, sleep quality, some biochemical and cardiometabolic indices, cortisol, brain-derived neurotrophic factor (BDNF), high-sensitivity C-reactive protein (hs-CRP), and oxidative stress indicators will be assessed.DiscussionThe use of dietary interventions in the management of T2DM complications is practical and safe. This research seeks to investigate the capacity of the MIND diet in the management of insomnia and cardiovascular problems of DM. It is expected that the results of this research will provide new perspectives on using an ideal dietary regimen to treat these health conditions.Trial registrationIRCT20181111041611N8. Registered on August 7, 2023. https://www.irct.ir/trial/71772

Effect of chia seeds or concentrated fish oil on cardiometabolic risk markers in subjects with hypertriglyceridaemia: a parallel clinical trial.

The beneficial effects of n-3 polyunsaturated fatty acids (PUFA) in reducing high blood triglyceride (TG) levels have been well demonstrated. This study aimed to investigate the effect of chia seeds on blood TG and its associated cardiometabolic factors in hypertriglyceridaemic individuals. This three-group randomised controlled trial compared the effects of a low-calorie diet (n = 22), a low-calorie diet with chia seeds (30 g/day, n = 22) or a low-calorie diet with concentrated fish oil (1.8 g/day of n-3 long-chain PUFAs, n = 22) in patients with hypertriglyceridaemia. Anthropometrics, fasting blood lipids, proprotein convertase subtilisin/kexin type 9, insulin, adiponectin, leptin and interleukin-6 levels were measured. After 8 weeks, the mean reduction in weight exhibited by the three groups was not statistically different (2.0, 2.7 and 2.8 kg, respectively, for the control, fish oil and chia seed groups). The plasma TG decreased in both the chia seed and fish oil groups in comparison to the control group (p = 0.001). However, no significant difference was observed between the chia seed and fish oil groups (change from baseline mean: 145.2 and 136.7 mg/dL for the chia seed and fish oil groups, respectively). The consumption of chia seeds was associated with a reduction in diastolic blood pressure (change from baseline mean: 8.4 mmHg) compared to the other two groups. No significant alterations were observed in the other blood biochemical factors between the three groups. In people with moderate hypertriglyceridaemia, a low-calorie diet with 30 g of chia seeds compared to fish oil supplements containing 1.8 g of long-chain PUFAs has a similar effect on reducing plasma TG levels, whereas it has a higher blood pressure-lowering effect.

Calorie restriction modulates mitochondrial dynamics and autophagy in leukocytes of patients with obesity

Although it is established that caloric restriction offers metabolic and clinical benefits, the molecular mechanisms underlying these effects remain unclear. Thus, this study aimed to investigate whether caloric restriction can modulate mitochondrial function and remodelling and stimulate autophagic flux in the PBMCs of patients with obesity. This was an interventional study of 38 obese subjects (BMI > 35 kg/m2) who underwent 6 months of dietary therapy, including a 6-week very-low-calorie diet (VLCD) followed by an 18-week low-calorie diet (LCD). We determined clinical variables, mitochondrial function parameters (by fluorescence imaging of mitochondrial ROS and membrane potential), and protein expression of markers of mitochondrial dynamics (MNF1, MFN2, OPA, DRP1 and FIS1) and autophagy (LC3, Beclin, BCL2 and NBR1) by western blot. Caloric restriction induced an improvement in metabolic outcomes that was accompanied by an increase in AMPK expression, a decrease of mitochondrial ROS and mitochondrial membrane potential, which was associated with increased markers of mitochondrial dynamics (MFN2, DRP1 and FIS1) and activation of autophagy as evidenced by augmented LC3 II/I, Beclin1 and NBR1, and a decrease in BCL2. These findings shed light on the specific molecular mechanisms by which caloric restriction facilitates metabolic improvements, highlighting the relevance of pathways involving energy homeostasis and cell recovery, including mitochondrial function and dynamics and autophagy.

Protocol for a feasibility multi-centre randomised controlled trial of a pre-operative two-week very low-calorie diet to reduce steatosis prior to liver resection (RESOLVE)

BackgroundHepatic steatosis (HS) increases morbidity and mortality associated with liver surgery (LS). Furthermore, patients with HS are more likely to require a blood transfusion, which is associated with worse short and long-term outcomes. Patients with HS requiring LS receive no specific dietary treatment or advice. A very low-calorie diet (VLCD) is commonly used before gallbladder and bariatric surgery to reduce liver volumes and associated intraoperative morbidity. These diets typically provide 800–1200 kcal/day over a 2–4-week period. Limited evidence suggests that a VLCD in patients with LS may result in better outcomes.MethodsThis study aims to test the feasibility of delivering a multi-centre randomised clinical trial to compare a dietary intervention (VLCD plus motivational instructions) versus treatment as usual (TAU) in people with HS having LS. This study will provide high-quality data to estimate screening rates, recruitment, randomisation, retention, and intervention adherence. The study will also determine the definitive trial’s most clinically relevant primary outcome. The study will also estimate resource use and costs associated with the delivery of the intervention. Seventy-two adults ≥ 18 who are scheduled to undergo elective LS and have a magnetic resonance imaging (MRI) identified HS will be recruited. Acceptability to the dietary intervention will be evaluated with food diaries and focus groups. Clinical and patient-reported outcomes will be collected at baseline, pre- and post-surgery, day of discharge, plus 30- and 90-day follow-up.DiscussionThis feasibility study will provide data on the acceptability and feasibility of a dietary intervention for patients with HS having LS. The intervention has been developed based on scientific evidence from other clinical areas and patient experience; therefore, it is safe for this patient group. Patients with experience of LS and VLCDs have advised throughout the development of the study protocol. The findings will inform the design of a future definitive study.Trial registrationISRCTN Number 19701345. Date registered: 20/03/2023. URL: https://www.isrctn.com/ISRCTN19701345.

Long-Term Randomized Controlled Trials of Diet Intervention Reports and Their Impact on Cancer: A Systematic Review.

Most randomized controlled trials (RCTs) assessing the impact of diet on cancer have been short term (<1 year), mostly evaluating breast cancer survivors. Given the many-year interval that is generally required for an intervention to have an impact on cancer risk or prognosis, as well as the fact that lifestyle strategies such as diet modification frequently fail due to lack of adherence over the long term, we focused this systematic review only on longer-term (≥1 year) intervention reports. Diet intervention reports focused on reducing cancer risk in overweight and obese individuals target caloric restriction (every day, some days, or most hours of each day). This study is a systematic review of RCTs lasting at least 1 year, testing dietary interventions with a primary or secondary endpoint of cancer or a biomarker linked to cancer. Fifty-one reports met our review criteria. Twenty of fifty-one (39%) reports are RCTs where the primary endpoint was cancer or a cancer-related biomarker, while the other reports evaluated reports where cancer or a cancer-related biomarker was a secondary endpoint. Thirteen of twenty (65%) primary reports evaluated isocaloric, and the remaining eight evaluated low-calorie diets. All but one of the primary and two secondary isocaloric diet reports evaluated the benefit of a low-fat diet (LFD), with the other three evaluating a Mediterranean diet (MedD). More LCD vs. isocaloric diet primary reports (71% vs. 38%) demonstrated cancer or cancer-related biomarker benefit; the difference in chance of benefit with secondary reports was 85% for LCD vs. 73% for isocaloric diets. Three of three MedD reports demonstrated benefit. Sixty-nine percent (20/29) of the secondary reports came from two large reports: the WHI diet modification trial (15 secondary reports) and the polyp prevention trial (5 secondary reports). Nineteen of twenty-two (86%) primary reports enrolled only women, and three enrolled both men and women. No study that met our criteria enrolled only men, comprising 1447 men in total vs. 62,054 women. Fifteen of twenty (75%) primary reports focus on healthy women or women with breast cancer. Adherence findings are discussed when provided. More long-term RCTs evaluating cancer and cancer-related biomarker endpoints are needed, especially for cancers at sites other than the breast.