Efficacy of low- and very-low-energy diets in people with type 2 diabetes mellitus: A systematic review and meta-analysis of interventional studies

Behavior change techniques in low-calorie and very low-calorie diet interventions for weight loss: A systematic review with meta-analysis

BACKGROUND

There is limited evidence and clinical guidelines on the behavior change support required for low-calorie diet programs. This systematic review aimed to establish the behavior change technique(s) (BCT) implemented in weight loss interventions (≤1200 kcal/d) and how these contribute to effectiveness.

METHODS

Databases were searched from inception to April 2022. Screening, data extraction, BCT coding, and quality appraisal were conducted in duplicate using the Template for Intervention Description and Replication framework, Behavior Change Technique Taxonomy, and Cochrane Risk of Bias 2 tool. Data were analyzed via narrative synthesis and random effects multi-level meta-analyses.

RESULTS

Thirty-two papers reporting on 27 studies were included. Twenty-four BCTs were identified across studies. Eight BCTs were significantly associated with a larger reduction in weight at the end-of-diet time-point; one BCT was statistically significant at the end of weight maintenance. Physical activity, Type 2 Diabetes, and BMI category moderated intervention effects.

CONCLUSIONS AND IMPLICATIONS

This is the first meta-analysis to examine how specific BCTs contribute to the effectiveness of low-calorie diets. It is recommended that a) these findings are used to develop clinical guidelines specific to behavioral support in low-calorie diet programs, and b) program commissioners stipulate the use of these BCTs in their service specifications.

Metabolic effects of very-low calorie diet, Semaglutide, or combination of the two, in individuals with type 2 diabetes mellitus

BACKGROUND & AIMS

Very-low calorie diets (VLCD) and the glucagon-like peptide-1 receptor agonist (GLP1RA) Semaglutide induce significant weight loss and improve glycaemic control in individuals with type 2 diabetes (T2D). This pilot study was conducted to explore the comparative short-term effects of these interventions individually, and in combination, on weight, body composition and metabolic outcomes.

METHODS

Thirty individuals with T2D (age 18-75 years, BMI 27-50  kg m-2) were randomly assigned to receive Semaglutide (SEM), 800 kilocalorie/day VLCD (VLCD), or both in combination (COMB) for 12 weeks. Measurement of weight and glycated haemoglobin (HbA1c), dual energy X-ray absorptiometry, and intravenous glucose tolerance tests (IVGTT) were performed at baseline and post-intervention. Diet diaries were utilised to assess compliance. Insulin first phase response during IVGTT provided a marker of pancreatic beta-cell function, and insulin sensitivity was estimated using HOMA-IR.

RESULTS

Significantly greater reductions in body weight and fat mass were observed in VLCD and COMB, than SEM (p < 0.01 v both). VLCD and COMB resulted in a 5.4 and 7 percentage-point greater weight loss than SEM, respectively. HbA1c and fasting glucose reduced significantly in all groups, however fasting insulin and HOMA-IR improved in VLCD and COMB only. Insulin first phase response during IVGTT increased in SEM and COMB, and this increase was significantly greater in COMB than VLCD (p < 0.01).

CONCLUSION

VLCD elicited greater short-term losses of weight and fat mass than Semaglutide. Adding VLCD to Semaglutide stimulated further weight loss than Semaglutide alone. The combination did not yield any additive effects on weight and body composition above VLCD alone, but did provoke greater improvements in pancreatic beta-cell function. Thus, combination of Semaglutide and VLCD warrants further exploration as a novel approach to T2D management.

Role of lifestyle and glucagon-like peptide-1 receptor agonists for weight loss in obesity, type 2 diabetes and steatotic liver diseases

BACKGROUND

The current obesity pandemic has given rise to associated comorbidities and complications, including type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD). During the last decade, certain glucagon-like peptide 1 receptor agonists (GLP-1RA), originally developed as antihyperglycemic drugs, also demonstrated efficacy for weight loss.

AIMS

To review shared pathophysiologic features of common metabolic diseases and compare therapeutic strategies to reduce body weight and related complications.

METHODS

We performed an extensive literature research to describe the effects of lifestyle modification, first-generation anti-obesity drugs, and GLP-1RA on weight loss in humans with obesity, type 2 diabetes and MASLD.

RESULTS

Until recently, treatment of obesity has been limited to lifestyle modification, which offer moderate degree and sustainability of weight loss. The few approved first-generation anti-obesity drugs are either limited to short term use or to certain forms of obesity. Some GLP-1RA significantly decrease caloric intake and body weight. Liraglutide and semaglutide have therefore been approved for treating people with obesity. They also lead to a reduction of hepatic fat content and inflammation in people with biopsy-confirmed MASLD. Possible limitations comprise adverse effects, treatment adherence and persistence.

CONCLUSION

Certain GLP-1RA are superior to lifestyle modification and first-generation anti-obesity drugs in inducing weight loss. They have therefore markedly changed the portfolio of obesity treatment with additional beneficial effects on steatotic liver disease.

Addressing uncertainty about the role of structured lifestyle modification for metabolic surgery patients

There is good evidence that structured lifestyle modification programmes improve health in patients with metabolic and cardiovascular disorders, but there is no specific evidence that they improve outcomes in patients undergoing metabolic or obesity surgery. Despite expert consensus guidelines stating this fact, some healthcare systems still compel patients to participate in a structured lifestyle modification programme prior to metabolic or obesity surgery. There is a well-established need for individualised multidisciplinary dietetic and physical activity care for metabolic and obesity surgery patients, and the benefits of intentional weight loss prior to surgery are well proven, but these are distinct from potentially harmful requirements for patients to undertake compulsory structured lifestyle programmes of fixed duration, frequency and intensity, which may delay surgery and reinforce obesity stigma. A critical step in rejuvenating metabolic surgery is to reframe patient participation in structured lifestyle modification programmes as an opportunity for education and empowerment, not as an indicator of motivation or suitability for metabolic surgery. Large, well-designed and adequately powered clinical trials are needed to address uncertainties in the evidence base for these programmes. Given genuine equipoise, they will need to determine whether "surgery plus lifestyle" is superior to "surgery plus placebo". Moreover, they will need to determine the cost-effectiveness of these programmes and identify some of the factors giving rise to the substantial heterogeneity in responses to structured lifestyle modification.

Is Type 2 Diabetes Mellitus a Behavioural Disorder? An Evidence Review for Type 2 Diabetes Mellitus Prevention and Remission through Lifestyle Modification

The prevalence of type 2 diabetes mellitus (T2DM) is steadily rising worldwide due to an increasingly sedentary lifestyle combined with unhealthy food habits. Currently, the burden of diabetes on healthcare systems is unprecedented and rising daily. Several observational studies and randomized controlled trials provide clinical evidence that T2DM remission is possible by adopting dietary interventions and a strict exercise training protocol. Notably, these studies provide ample evidence for remission in patients with T2DM or for prevention in those with risk factors for the disease through various non-pharmacological behavioural interventions. In this article, we present two clinical cases of individuals who showed remission from T2DM/prediabetes via behavioural changes, especially through the adoption of a low-energy diet and exercise. We also discuss the recent advances in T2DM and obesity research, focusing on nutritional interventions and exercise and their benefits for weight loss, improved metabolic profile, enhanced glycaemic control and remission of diabetes.

[What is confirmed in the treatment of obesity?]

Obesity is a chronic disease. Obesity and the associated sequelae not only lead to an increased morbidity and mortality but also to a reduced quality of life. People with obesity are often stigmatized and are not offered adequate professional treatment although evidence-based treatment options are available. According to current guidelines a multimodal, interdisciplinary and individualized obesity treatment must always be carried out. For most patients with advanced obesity structured multimodal therapy programs and/or bariatric surgery (with accompanying conservative measures) are the treatment of choice. The treatment spectrum is supplemented by pharmaceuticals, supportive fields and online offers. As obesity is a chronic disease any time-limited treatment is mostly futile. Treatment of obesity must therefore be organized in a professional and long-term manner.

Efficacy of Dietary and Supplementation Interventions for Individuals with Type 2 Diabetes

The prevalence of Type 2 diabetes (T2D) is increasing, which creates a large economic burden. Diet is a critical factor in the treatment and management of T2D; however, there are a large number of dietary approaches and a general lack of consensus regarding the efficacy of each. Therefore, the purpose of this narrative review is twofold: (1) to critically evaluate the effects of various dietary strategies on diabetes management and treatment, such as Mediterranean diet, plant-based diet, low-calorie and very low-calorie diets, intermittent fasting, low-carbohydrate and very low-carbohydrate diets, and low glycemic diets and (2) to examine several purported supplements, such as protein, branched-chain amino acids, creatine, and vitamin D to improve glucose control and body composition. This review can serve as a resource for those wanting to evaluate the evidence supporting the various dietary strategies and supplements that may help manage T2D.

Effects of time-restricted feeding in weight loss, metabolic syndrome and cardiovascular risk in obese women

BACKGROUND

The increasing prevalence of overweight and obesity among the worldwide population has been associated with a range of adverse health consequences such as Type 2 diabetes and cardiovascular diseases. The metabolic syndrome (MetS) is a cluster of cardiometabolic abnormalities that occur more commonly in overweight individuals. Time-restricted feeding (TRF) is a dietary approach used for weight loss and overall health. TRF may be an option for those subjects who struggle with extreme restriction diets with foods that generally do not belong to an individual's habits.

OBJECTIVE

The purpose of this study was to determine the effect of TRF on body composition and the association of weight loss with metabolic and cardiovascular risks in obese middle-aged women.

METHODS

A non-randomized controlled clinical trial was performed over 3 months in obese women (TRF group, n = 20, BMI 32.53 ± 1.13 vs. Control n = 12, BMI 34.55 ± 1.20). The TRF protocol adopted was 16 h without any energy intake followed by 8 h of normal food intake.

MAIN OUTCOMES AND MEASURES

Anthropometric measurements, body composition, blood biomarkers, cardiovascular risk in 30 years (CVDRisk30y), and quality of life were evaluated at baseline and after the 3 months.

RESULTS

TRF was effective in reducing weight (~ 4 kg), BMI, % of body fat (%BF), waist circumference from baseline without changes in blood biomarkers associated with MetS. TRF promoted a reduction in CVDRisk30y (12%) wich was moderately correlated with %BF (r = 0.62, n = 64, p < 0.001) and %MM (r = - 0.74, n = 64, p < 0.001).

CONCLUSIONS

TRF protocol reduces body weight without changes in biomarkers related to MetS. In addition, the anthropometric evaluation that predicts %BF and %MM could be used as an approach to follow individuals engaged in the TRF regimen since they correlate with cardiovascular risk.

Effects of a low-energy diet with and without oat bran and olive oil supplements on body mass index, blood pressure, and serum lipids in diabetic women: A randomized controlled trial

Type 2 diabetes is an epidemic public health issue worldwide. It is common among adults and is more severe among overweight and obese subjects. This study was conducted to evaluate the effects of a low-energy diet with and without oat bran and olive oil supplements on body mass index, blood pressure, and serum lipids in women with diabetes. It was conducted for three months among 78 participants after dividing them into six groups. Groups 2 to 6 were received low-energy diet (1,600 kcal/day), with or without oat bran (10 g/day) and olive oil (5 g/day) supplements. Weight, height, blood pressure, and serum lipids were measured. A low-energy diet with and without oat bran and olive oil supplements lowers body mass index in subjects by 0.9%-6.0% on average. It also lowers systolic and diastolic blood pressure by 1.0%-9.0% and 4.8%-12.6%, respectively. Serum triglycerides were declined in groups 2, 3, and 4 by 27.2%, 17.3%, and 1.7%, respectively, but not significantly. Total cholesterol was dropped significantly by 8.3% only when the low-energy diet was used with oat bran supplement among obese subjects, while LDL cholesterol was dropped significantly by 20.0% only when it was used with oat bran and olive oil supplements among subjects with high serum triglycerides. Proper control of type 2 diabetes among overweight and obese adults is needed to control cardiovascular complications. This could be accomplished by following a low-energy diet and incorporating healthy foods such as oat and olive oil into the usual diet.

Efficacy of Intermittent or Continuous Very Low-Energy Diets in Overweight and Obese Individuals with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analyses

OBJECTIVE

This study is aimed at investigating the efficacy of a very low-energy diet (VLED) in overweight and obese individuals with type 2 diabetes mellitus (T2DM).

METHODS

We thoroughly searched eight electronic resource databases of controlled studies concerning the efficacy and acceptability of intermittent or continuous VLEDs in patients with T2DM compared with other energy restriction interventions.

RESULTS

Eighteen studies (11 randomized and seven nonrandomized controlled trials) with 911 participants were included. The meta-analyses showed that compared with a low-energy diet (LED) and mild energy restriction (MER), VLED is superior in the reduction of body weight (mean difference (MD) MD_LED = -2.77, 95% confidence interval (CI) CI_LED = -4.81 to - 0.72, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, I ² = 0%) and TG level (MD = -0.25, 95%CI = -0.55 to 0.06, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, I ² = 0%) and TG level (MD = -0.25, 95%CI = -0.55 to 0.06, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39, P _LED = 0.008; MD_MER = -6.72, 95%CI_MER = -10.05 to - 3.39.

CONCLUSION

Dietary intervention through VLEDs is an effective therapy for rapid weight loss, glycemic control, and improved lipid metabolism in overweight and obese individuals with T2DM. Thus, VLEDs should be encouraged in overweight and obese individuals with T2DM who urgently need weight loss and are unsuitable or unwilling to undergo surgery. As all outcome indicators have low or extremely low quality after GRADE evaluation, further clinical trials that focus on the remission effect of VLEDs on T2DM are needed.