Very low calorie diet (VLCD): a useful alternative in the treatment of the obese NIDDM patient

Intermittent fasting and time-restricted eating role in dietary interventions and precision nutrition

Intermittent fasting (IF), time-restricted eating (TRE) and fasting-mimicking diets (FMD) are gaining popularity as weight loss programs. As such, the timing and frequency of meals have been recognized as essential contributors to improving cardiometabolic health and a role as adjuvant therapy in cancer. Randomized controlled trials suggested that the weight loss associated with IF is due to a reduced energy intake due to time restriction. Although the supervised TRE clinical trials documented the dietary caloric intake, many free-living studies focused on the timing of meals without a complete characterization of the dietary intake, caloric density, or macronutrient composition. It is possible that both caloric-restriction diets and time-restriction protocols could work synergistically or additively to improve metabolic health outcomes. Like personalized medicine, achieving precision nutrition mandates the provision of the right nutrients to the right patient at the right time. To accomplish this goal, future studies need to evaluate the benefits of IF and TRE. Randomized controlled trials were conducted in different populations, ethnic groups, ages, geographic distribution, physical activity levels, body composition and in patients with obesity, diabetes, and cardiovascular diseases. Also, it is crucial to analyze the dietary composition and caloric density as related to circadian rhythm and timing of meals. It is conceivable that IF and TRE may contribute to precision nutrition strategies to achieve optimal health. However, more research is needed to evaluate IF and TRE effects on health outcomes and any side effects.

Very Low-Calorie Ketogenic Diet: A Potential Application in the Treatment of Hypercortisolism Comorbidities

A very low-calorie ketogenic diet (VLCKD) is characterized by low daily caloric intake (less than 800 kcal/day), low carbohydrate intake (<50 g/day) and normoproteic (1−1.5 g of protein/kg of ideal body weight) contents. It induces a significant weight loss and an improvement in lipid parameters, blood pressure, glycaemic indices and insulin sensitivity in patients with obesity and type 2 diabetes mellitus. Cushing’s syndrome (CS) is characterized by an endogenous or exogenous excess of glucocorticoids and shows many comorbidities including cardiovascular disease, obesity, type 2 diabetes mellitus and lipid disorders. The aim of this speculative review is to provide an overview on nutrition in hypercortisolism and analyse the potential use of a VLCKD for the treatment of CS comorbidities, analysing the molecular mechanisms of ketogenesis.

Effects of intermittent very-low calorie diet on glycemic control and cardiovascular risk factors in obese patients with type 2 diabetes mellitus: A randomized controlled trial

AIMS/INTRODUCTION

Very few studies assess the effectiveness of different protocols of intermittent very-low calorie diet (VLCD) in patients with diabetes. This study was designed to compare the effects of 2 days/week and 4 days/week of intermittent VLCD on glycemic control, diabetes remission, metabolic parameters and quality of life in patients with type 2 diabetes and obesity.

MATERIALS AND METHODS

Participants with obesity and type 2 diabetes were recruited and randomly assigned to three groups, consisting of control, 2 days/week and 4 days/week of intermittent VLCD. In the intermittent VLCD groups, participants received a 600-kcal diet per day on restricted days and ad libitum food consumption on non-restricted days. Glycemic control, rate of diabetes remission, metabolic parameters and quality of life were evaluated at baseline, weeks 2, 10 and 20.

RESULTS

A total of 40 participants were enrolled. The mean body mass index was 30.1 ± 5.9 kg/m2 , and the mean glycated hemoglobin was 7.4 ± 1.2%. At week 20, there was an improvement in glycemic control in both intermittent VLCD groups with significant decreases in glycated hemoglobin levels and insulin resistance index throughout the study periods. Diabetes remission without the need for medications was equally found in 29% of participants in both intermittent VLCD groups. Serum triglyceride, bodyweight, body mass index and fat mass were also significantly decreased in both VLCD groups. No serious adverse events were encountered.

CONCLUSION

Intermittent VLCD was highly effective in achieving optimal glycemic control. The effects of 2 days/week and 4 days/week of intermittent VLCD on diabetes remission were relatively similar.

The ketogenic diet corrects metabolic hypogonadism and preserves pancreatic ß-cell function in overweight/obese men: a single-arm uncontrolled study

BACKGROUND

Overweight and obesity are increasingly spread in our society. Low testosterone levels are often present in these patients, the so-called metabolic hypogonadism, that further alters the metabolic balance in a sort of vicious cycle. Very low-calorie ketogenic diet (VLCKD) has been reported to efficiently reduce body weight, glycaemia, and the serum levels of insulin, glycated hemoglobin, but its effects on β-cell function and total testosterone (TT) levels are less clear.

AIM

To evaluate the effects of VLCKD on markers suggested to be predictive of β-cell dysfunction development, such as proinsulin or proinsulin/insulin ratio, and on TT values in a cohort of overweight or obese nondiabetic male patients with metabolic hypogonadism.

METHODS

Patients with overweight or obesity and metabolic hypogonadism underwent to VLCKD for 12 weeks. Anthropometric parameters, blood testing for the measurement of glycaemia, insulin, C-peptide, proinsulin, TT, calculation of body-mass index (BMI), and HOMA index were performed before VLCKD and after 12 weeks.

RESULTS

Twenty patients (mean age 49.3 ± 5.2 years) were enrolled. At enrollement all patients presented increased insulin, HOMA index, C-peptide, and proinsulin levels, whereas the proinsulin/insulin ratio was within the normal values. After VLCKD treatment, body weight and BMI significantly decreased, and 14.9 ± 3.9% loss of the initial body weight was achieved. Glycaemia, insulin, HOMA index, C-peptide, and proinsulin significantly decreased compared to pre-VLCKD levels. Serum glycaemia, insulin, C-peptide, and proinsulin levels returned within the normal range in all patients. No difference in the proinsulin/insulin ratio was observed after VLCKD treatment. A mean increase of 218.1 ± 53.9% in serum TT levels was achieved and none of the patients showed TT values falling in the hypogonadal range at the end of the VLCKD treatment.

CONCLUSIONS

This is the first study that evaluated the effects of VLCKD on proinsulin, proinsulin/insulin ratio, and TT levels. VLCKD could be safely used to improve β-cell secretory function and insulin-sensitivity, and to rescue overweight and obese patients from β-cell failure and metabolic hypogonadism.

Metabolic Impact of Intermittent Fasting in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Interventional Studies

CONTEXT

Intermittent fasting (IF) has been proposed as a weight-loss strategy with additional cardiometabolic benefits in individuals with obesity. Despite its growing popularity, the effect of IF in patients with type 2 diabetes (T2DM) remains unclear.

OBJECTIVE

We conducted a systematic review and meta-analysis to evaluate the metabolic impact of IF compared to standard diet in patients with T2DM.

METHODS

Embase, PubMed, and clinicaltrials.gov between 1950 and August 12, 2020 were searched for randomized, diet-controlled studies evaluating any IF intervention in adults with T2DM. We examined the impact of IF on weight loss and glucose-lowering by calculating pooled estimates of the absolute differences in body weight and glycated hemoglobin A1c (HbA1c) compared to a control group using a random-effects model.

RESULTS

Seven studies (n = 338 participants; mean body mass index [BMI] 35.65, mean baseline HbA1c 8.8%) met our inclusion criteria. IF induced a greater decrease in body weight by -1.89 kg (95% CI, -2.91 to -0.86 kg) compared to a regular diet, with no significant between-study heterogeneity (I2 21.0%, P = .28). The additional weight loss induced by IF was greater in studies with a heavier population (BMI > 36) (-3.43 kg [95% CI, -5.72 to -1.15 kg]) and in studies of shorter duration (≤ 4 months) (-3.73 kg [95% CI, -7.11 to -0.36 kg]). IF was not associated with further reduction in HbA1c compared to a standard diet (HbA1c -0.11% [95% CI, -0.38% to 0.17%]).

CONCLUSION

Current evidence suggests that IF is associated with greater weight loss in patients with T2DM compared with a standard diet, with a similar impact on glycemic control.

Efficiency of a 15-Week Weight-Loss Program, Including a Low-Calorie Formula Diet, on Glycemic Control in Patients with Type 2 Diabetes Mellitus and Overweight or Obesity

INTRODUCTION

Patients who are overweight or obese have an increased risk of developing type 2 diabetes mellitus (T2DM). Weight loss can have a positive effect on glycemic control.

OBJECTIVE

We aimed to investigate glycemic control in patients with T2DM and overweight or obesity during a structured weight-loss program.

METHODS

This was a prospective, interventional study. We recruited 36 patients (14 men and 22 women) with a median age of 58.5 years and median body mass index (BMI) of 34.1, to a 15-week structured weight-loss program with a low-calorie (800 kcal) formula diet for 6 weeks. The primary end point, HbA1c level, and secondary end points, anthropometric data, medication, and safety, were assessed weekly. Laboratory values and quality of life were assessed at baseline and after 15 weeks.

RESULTS

HbA1c decreased from 7.3% at baseline to 6.5% at 15 weeks (p < 0.001), median body weight by 11.9 kg (p < 0.001), median BMI by 4.3 (p < 0.001) and median waist circumference by 11.0 cm (p < 0.001). Two participants discontinued insulin therapy, 4 could reduce their dosage of oral antidiabetic agents, and 6 completely discontinued their antidiabetic medication. Insulin dose decreased from 0.63 (0.38-0.89) to 0.39 (0.15-0.70) units/kg body weight (p < 0.001). No patient experienced hypoglycemic episodes or hospital emergency visits. Triglycerides and total cholesterol decreased as well as surrogate markers of liver function. However, the levels of high-density and low-density lipoprotein cholesterol (HDL-C and LDL-C) as well as uric acid remain unchanged. Regarding quality of life, the median physical health score increased from 44.5 (39.7-51.4) at baseline to 48.0 (43.1-55.3; p = 0.007), and the median mental health score decreased from 42.1 (36.1-46.7) to 37.4 (30.3-43.7; p = 0.004).

CONCLUSIONS

A structured weight-loss program is effective in the short term in reducing HbA1c, weight, and antidiabetic medication in patients with T2DM who are overweight or obese. Levels of HDL-C and LDL-C were not affected by short-term weight loss. The decline in mental health and the long-term effects of improved glycemic control require further trials.

Adjuvant Therapies in Diabetic Retinopathy as an Early Approach to Delay Its Progression: The Importance of Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a progressive disease induced by a sustained state of chronic hyperglycemia that can lead to several complications targeting highly metabolic cells. Diabetic retinopathy (DR) is a multifactorial microvascular complication of DM, with high prevalence, which can ultimately lead to visual impairment. The genesis of DR involves a complex variety of pathways such as oxidative stress, inflammation, apoptosis, neurodegeneration, angiogenesis, lipid peroxidation, and endoplasmic reticulum (ER) stress, each possessing potential therapeutic biomarkers. A specific treatment has yet to be developed for early stages of DR since no management is given other than glycemic control until the proliferative stage develops, offering a poor visual prognosis to the patient. In this narrative review article, we evaluate different dietary regimens, such as the Mediterranean diet, Dietary Pattern to Stop Hypertension (DASH) and their functional foods, and low-calorie diets (LCDs). Nutraceuticals have also been assessed in DR on account of their antioxidant, anti-inflammatory, and antiangiogenic properties, which may have an important impact on the physiopathology of DR. These nutraceuticals have shown to lower reactive oxygen species (ROS), important inflammatory factors, cytokines, and endothelial damage biomarkers either as monotherapies or combined therapies or concomitantly with established diabetes management or nonconventional adjuvant drugs like topical nonsteroidal anti-inflammatory drugs (NSAIDs).

Very-low-calorie ketogenic diet (VLCKD) in the management of metabolic diseases: systematic review and consensus statement from the Italian Society of Endocrinology (SIE)

BACKGROUND

Weight loss is a milestone in the prevention of chronic diseases associated with high morbility and mortality in industrialized countries. Very-low calorie ketogenic diets (VLCKDs) are increasingly used in clinical practice for weight loss and management of obesity-related comorbidities. Despite evidence on the clinical benefits of VLCKDs is rapidly emerging, some concern still exists about their potential risks and their use in the long-term, due to paucity of clinical studies. Notably, there is an important lack of guidelines on this topic, and the use and implementation of VLCKDs occurs vastly in the absence of clear evidence-based indications.

PURPOSE

We describe here the biochemistry, benefits and risks of VLCKDs, and provide recommendations on the correct use of this therapeutic approach for weight loss and management of metabolic diseases at different stages of life.

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

AIMS

To review systematically and quantify the weight loss achieved through low- (LEDs) and very-low-energy diets (VLEDs) in people with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Studies reporting the effects of diet-only interventions of up to 1600 kcal/d in people with T2DM were searched in MEDLINE, EMBASE and CINAHL up to July 2018. Changes in the primary (body weight and body mass index [BMI]) and secondary outcomes (glycated haemoglobin, blood lipids) according to energy restriction and duration of diet were modelled using restricted cubic splines.

RESULTS

Forty-four studies (3817 participants) were included. The overall quality of the evidence was moderate and limited to short-term interventions up to 4 months. Baseline mean weight and BMI were 92.1 kg and 36.6 kg/m² . VLEDs of 400 kcal/d led to 5.4% weight loss at 2 weeks, increasing to 17.9% at 3 months. More modest reductions of 7.3% were observed on LEDs of 1200 kcal/d and 2.0% on 1600 kcal/d after 3 months. No clear patterns emerged for secondary outcomes. Publication bias was significant for primary outcomes.

CONCLUSIONS

Through modelling, we were able to describe effective dietary deficit strategies to achieve weight reduction up to 4 months in people with T2DM. High-quality studies are required to further support clinical practice with evidence-based dietary interventions.

Immediate and long-term effects of a very-low-calorie diet on diabetes remission and glycemic control in obese Thai patients with type 2 diabetes mellitus

AIM

A very-low-calorie diet (VLCD) can reverse the underlying defects of type 2 diabetes mellitus (DM) in obese subjects. We determined the efficacy, safety, and durability of VLCD in Thai patients with DM and obesity.

METHODS

Twenty Thai patients with DM and obesity were enrolled. After a 2-week trial, VLCD (600 kcal/day) was continued for 8 weeks, followed by a 4-week transition period. Data on diabetes remission (fasting plasma glucose level <126 mg/dl and HbA1c <6.5% without the use of glucose-lowering medications), glycemic control, metabolic parameters, and quality of life (QOL) were collected along with indices of insulin resistance (IR) and beta cell function. Glycemic control 12 months after discontinuation of VLCD was also examined.

RESULTS

Among 19 patients (age 48 ± 2 years, BMI 27.7 kg/m2) who completed the study, rapid improvement in glycemic control was observed in the first 2 weeks of VLCD. At both 8 and 12 weeks, diabetes remission was achieved in 79%. Significant weight loss was accompanied by a significant reduction in IR and an increase in beta cell function, starting at 4 weeks of VLCD. QOL also significantly increased. At 12 months after VLCD, however, DM remission was achieved in approximately 30%.

CONCLUSION

Very-low-calorie diet was effective and safe in inducing short-term diabetes remission in Thai subjects by ameliorating beta cell function and IR. Optimal long-term glycemic control was potentially durable as one-third of subjects remained without diabetes medication 12 months after VLCD.

Effects on Diabetes Medications, Weight and Glycated Hemoglobin Among Adult Patients With Obesity and Type 2 Diabetes: 6-Month Observations From a Full Meal Replacement, Low-Calorie Diet Weight Management Program

OBJECTIVES

A 6-month weight-management program with full meal replacement, low-calorie diet (full MR-LCD) (900 kcal/day for 6 to 12 weeks) follows a protocol for patients with diabetes for decreasing or discontinuing weight-gaining diabetes medications first (Group WG) and then titrating weight-neutral medications (Group WN).

METHODS

This is a retrospective cohort study (1992 to 2009) of weight, glycemic control and diabetes medications changes in 317 patients with obesity and type 2 diabetes who were taking medications.

RESULTS

Group WG and Group WN were similar at baseline, except that glycated hemoglobin (A1C) levels were significantly lower in Group WN (7.5% vs. 6.6%; p<0.001). At 6 months, both groups had lost 16% of their weight, and the decreases or discontinuations of medications were 92.1% sulfonureas, 86.5% insulins, 78.8% thiazolidinediones, 77.8% alpha-glucosidase inhibitors, 50% meglitinides, 33.3% dipeptidyl peptidase-4 (DPP-4) inhibitors and 32.8% metformin. At 6 months, compared with baseline, A1C levels improved in Group WG and Group WN (6-month A1C levels 6.7% and 5.8%, respectively; p<0.0001), and Group WN had significantly better A1C levels than Group WG. At 6 months, 30% of patients were no longer taking diabetes medications and had significantly better percentages of weight loss compared with those taking medications (18.6% vs. 16%; p=0.002); both groups had improved glycemic control at 6 months (A1C 6.0% vs. A1C 6.6%; NS).

CONCLUSIONS

In patients with obesity and type 2 diabetes taking medications, a full MR-LCD program appears to be safe and includes improvement in A1C levels. At 6 months, the percentage of weight loss can be significantly better in patients who no longer require diabetes medications, and A1C levels are best controlled in patients who are on WN medications.

Intermittent energy restriction in type 2 diabetes: A short discussion of medication management

AIM

To discuss type 2 diabetes mellitus (T2DM) medication changes required during the popular 5:2 intermittent energy restriction (IER) diet.

METHODS

A search was conducted in MEDLINE, EMBASE, AMED, CINAHL and Cochrane library for original research articles investigating the use of very low calorie diets (VLCD) in people with T2DM. The search terms used included “VLCD” or “very low energy diet” or “very low energy restriction” or “IER” or “intermittent fasting” or “calorie restriction” or “diabetes mellitus type 2” and “type 2 diabetes”. Reference lists of selected articles were also screened for relevant publications. Only research articles written in English, which also included an explanation of medication changes were included. A recent pilot trial using the 5:2 IER method, conducted by our research group, will also be summarized.

RESULTS

A total of 8 studies were found that investigated the use of VLCD in T2DM and discussed medication management. Overall these studies indicate that the use of a VLCD for people with T2DM usually require the cessation of medication to prevent hypoglycemia. Therefore, the 5:2 IER method will also require medication changes, but as seen in our pilot trial, may not require total cessation of medication, rather a cessation on the 2 IER days only.

CONCLUSION

Guidelines outlined here can be used in the initial stages of a 2-d IER diet, but extensive blood glucose monitoring is still required to make the necessary individual reductions to medications in response to weight loss.

Obesity, diabetes and VLCDs

Excess weight gain is an increasing burden on individuals, societies and healthcare providers. The role of very low calorie diets (VLCD) in the treatment of overweight and obese people with diabetes is considered within the framework of a partnership between healthcare providers, a commercial organisation and the patient.

Long-term weight loss maintenance and management following a VLCD: a 3-year outcome

BACKGROUND

Effective weight loss treatment is important as obesity has severe health and socioeconomic repercussions. Emerging evidence suggests that rapid initial weight loss results in better long-term weight loss maintenance. This remains controversial and contradicts current recommendations for slower weight loss.

AIM

To determine the effect of a very low calorie diet (VLCD) with group-based behaviour therapy on weight loss and long-term weight management by means of a retrospective database analysis.

METHODS

Data for this retrospective analysis included participants who embarked on the LighterLife Total VLCD programme between 2007 and 2010, and whose weights at baseline and at least 12 months were available (n = 5965).

RESULTS

Data were available for 5965 individuals at 1 year, 2044 at 2 years and 580 at 3 years. At baseline, the majority of individuals were Caucasian (n = 5155), female (n = 5419), ≥ 40 years old (n = 4272), 49% were within the body mass index (BMI) range of 30-35 kg/m(2) while 51% had a BMI > 35 kg/m(2) . The average initial weight of the whole cohort was 99.1 kg (SD 16.6). Initial weight and BMI at entry onto programme, as well as numbers of weeks of weight loss were all significantly associated with weight loss achieved on the first weight loss attempt. Weight lost during the initial weight loss phase was the only factor, which was significantly associated with percentage weight loss maintenance for years 1, 2, and 3.

CONCLUSION

The findings of this retrospective analysis suggest that provided a longer term weight loss management programme is adhered to, large amounts of initial weight loss can result in important longer term weight loss maintenance in motivated individuals.

Clinical efficacy of a medically supervised outpatient high-protein, low-calorie diet program is equivalent in prediabetic, diabetic and normoglycemic obese patients

Objective:

Type 2 diabetes mellitus (T2DM) affects approximately 10% of Americans, while 79 million Americans are estimated to have glucose intolerance or prediabetes (pre-DM). The present study was designed to determine whether obese patients with pre-DM or T2DM would lose weight as effectively as obese normoglycemic patients, in a medically supervised high-protein, low-calorie-weight management program.

Method:

Patients enrolled in a self-paid, university-based, outpatient weight loss program using prescribed very-low-calorie diet (VLCD) (500–800 cal per day) or LCD diet (800–1200 cal per day), recommended exercise and group behavioral counseling were studied retrospectively. Patients entering the program for the first time and attending weekly clinic visits for more than 4 weeks were included in the analysis.

Results:

A total of 2093 obese patients, of whom 583 patients with pre-DM (fasting glucose ⩾100 and <126 mg dl⁻¹), 367 patients with T2DM and 1143 normoglycemic patients entered the program from 1991 to 2010, who met all the inclusion criteria were included in the analysis. The body weight at baseline was 104.0±20.0 kg for DM, 101.4±18.4 for pre-DM and 99.0±18.8 kg for non-DM. Weight loss and percent of weight loss within 12 months were analyzed using a linear mixed-effects model. There was no significant difference in weight loss between DM vs non-DM (P=0.4597) and pre-DM vs non-DM (P=0.6006) in 12 months. The length of enrollment in the program was positively correlated to weight loss rates in all patients (P<0.001).

Conclusion:

This study demonstrates that obese, pre-DM and DM patients all lost weight as effectively with VLCD or LCD over 12 months. Given the impact of weight loss on the progression of comorbid conditions, these data support the hypothesis that medically supervised diets, including VLCD and LCD, should be more widely used in the prevention and treatment of obese patients with pre-DM or T2DM.

Weight loss for individuals with type 2 diabetes following a very-low-calorie diet in a community-based setting with trained facilitators for 12 weeks

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Approximately 80% of people with type 2 diabetes mellitus (T2DM) are overweight or obese. Weight loss produces numerous benefits in T2DM. People with T2DM have difficulty losing and maintaining weight.

WHAT THIS STUDY ADDS

Provision of a very-low-calorie diet (VLCD) with group support and behaviour therapy for patients with T2DM is feasible within a community-based setting with trained facilitators. VLCD approaches for weight management in T2DM can achieve more than 90% of weight loss as compared with obese individuals without T2DM. Identification of the need to investigate the full impact of this approach in patients with T2DM by assessing changes in glycaemia, liver function and medication. Approximately 80% of people with type 2 diabetes mellitus (T2DM) are overweight or obese, and obesity compounds the cardiovascular risk of T2DM. The aim of this retrospective study was twofold: first, to investigate whether a 12-week community-based very-low-calorie diet (VLCD) programme can result in important weight loss; and second, to investigate any potential difference in the weight loss achieved using this community-based approach in individuals with and without T2DM. Three hundred and fifty-five participants with T2DM were matched for age, body mass index (BMI) and gender to participants without T2DM (total cohort comprised 204 males: 506 females (mean ± standard deviation); age (years) 54.0 ± 9.1; BMI (kg m(-2) ) 41.6 ± 8.1; weight (kg) 116.1 ± 25.1). The programme included a daily intake of 550 kcal in addition to group support and behaviour therapy provided by trained facilitators within a community-based setting. After 12 weeks, there was significant weight loss within each group when compared with baseline (T2DM: 115.0 ± 24.4 kg vs. 96.7 ± 21.4 kg, P < 0.0001; non-T2DM: 117.2 ± 25.8 kg vs. 97.3 ± 22.2 kg, P < 0.0001). At 12 weeks, weight change (-18.3 ± 7.3 kg vs. -19.9 ± 7.0 kg, P = 0.012) and BMI change (-6.7 ± 2.9 kg m(-2) vs. -7.1 ± 2.1 kg m(-2) , P = 0.011) were significantly less in the T2DM group when compared with the non-T2DM group. Our results suggest that the use of VLCD approaches for weight management in T2DM can achieve more than 90% of the weight loss seen in obese individuals without T2DM.

How best to use partial meal replacement in managing overweight or obese patients with poorly controlled type 2 diabetes

OBJECTIVE

To compare patient compliance and benefits, over 12 months, of 1 versus 2 partial meal replacement (PMR) for the management of overweight/obese subjects with inadequately controlled type 2 diabetes.

DESIGN AND METHODS

Thirty-six overweight patients with inadequately controlled type 2 diabetes (BMI > 27 kg/m(2) and HbA1c > 7.5% [58 mmol/mol]) were randomized to receive 1 or 2 PMR/day, while maintaining usual lifestyle. Subjects were seen monthly and adjustment of medications was made to prevent hypoglycemia. Compliance was assessed by counting unused sachets.

RESULTS

Patients on 2 PMR/day lost almost 4 kg compared with only 0.5 kg in the 1 PMR/day group. This difference was statistically significant (P < 0.05). Overall PMR was about 30% as effective as in our previous study on total meal replacement. Reductions in weight, waist, and HbA1c were better in the 2 PMR/day group while patient dropout and compliance were not worse over a 12-month period.

CONCLUSION

PMR provides a further management option for overweight/obese individuals with type 2 diabetes. The initial recommendation should be 2 PMR/day.

The effect of very low-calorie diets on renal and hepatic outcomes: a systematic review

Very low-calorie diets (VLCDs) are an effective means by which to induce clinically significant weight loss. However, their acceptance by health care practitioners and the public is generally lower than that for other nonsurgical weight loss methods. Whilst there is currently little evidence to suggest they have any detrimental effect on hepatic and renal health, data assessing these factors remain limited. We carried out a systematic review of the literature on randomized controlled trials that had a VLCD component and that reported outcomes for hepatic and renal health, published between January 1980 and December 2012. Cochrane criteria were followed, and eight out of 196 potential articles met the inclusion criteria. A total of 548 participants were recruited across the eight studies. All eight studies reported significant weight loss following the VLCD. Changes in hepatic and renal outcomes were variable but generally led to either no change or improvements in either of these. Due to the heterogeneity in the quality and methodology of the studies included, the effect of VLCDs on hepatic and renal outcomes remains unclear at this stage. Further standardized research is therefore required to fully assess the impact of VLCDs on these outcome measures, to better guide clinical practice.

The Prevention Of WEight Regain in diabetes type 2 (POWER) study: the effectiveness of adding a combined psychological intervention to a very low calorie diet, design and pilot data of a randomized controlled trial

Background

Obesity is of major pathogenetic importance to type 2 diabetes, it contributes to poor glycemic control and increases the risk of cardiovascular disease. Over 80% of patients with diabetes type 2 are overweight. To achieve a more favourable risk profile, changes in diet and lifestyle are needed. However, current treatment programs for obese DM type 2 patients are not effective in the long term. In this RCT, we compare the effectiveness of a Combined Psychological Intervention (CPI) and usual care in maintaining the favourable effects on weight and risk profile during 2 years of follow-up after a Very Low Calorie Diet (VLCD).

Methods and design

In a randomised parallel group intervention study, 140 patients with type 2 diabetes and overweight (BMI>27 kg/m2) will be recruited from the outpatient department of the Erasmus Medical Centre.

After obtaining ≥5% of weight loss with a VLCD, participants will be randomly assigned to CPI or usual care for 10 weeks. CPI consists of cognitive behaviour therapy, problem solving therapy and proactive coping.

Primary outcome measure is weight change (kg).

Other outcome measures are Body Mass Index (BMI = weight (kg)/length (m)2), waist circumference (cm), systolic blood pressure (mmHg), HbA1c (mmol/mol), lipid levels (LDL, HDL, TG (mmol/l) and chol/HDL-ratio), antidiabetic agents and doses, cardiovascular risk profile (UKPDS), lifestyle and quality of life (EuroQol EQ-5D). Psychosocial parameters are also studied, as secondary outcomes as well as determinants for weight loss.

When successful, we want to conduct an analysis of the cost effectiveness of the intervention as compared to usual care.

Discussion

We expect that a CPI after a VLCD will be effective in maintaining weight loss and improving cardiovascular risk and glycaemic control, while being cost-effective and improving quality of life in patients with type 2 diabetes.

Clinical trials registration

trialregister.nl NTR2264

Evidence of a metabolic memory to early-life dietary restriction in male C57BL/6 mice

Background

Dietary restriction (DR) extends lifespan and induces beneficial metabolic effects in many animals. What is far less clear is whether animals retain a metabolic memory to previous DR exposure, that is, can early-life DR preserve beneficial metabolic effects later in life even after the resumption of ad libitum (AL) feeding. We examined a range of metabolic parameters (body mass, body composition (lean and fat mass), glucose tolerance, fed blood glucose, fasting plasma insulin and insulin-like growth factor 1 (IGF-1), insulin sensitivity) in male C57BL/6 mice dietary switched from DR to AL (DR-AL) at 11 months of age (mid life). The converse switch (AL-DR) was also undertaken at this time. We then compared metabolic parameters of the switched mice to one another and to age-matched mice maintained exclusively on an AL or DR diet from early life (3 months of age) at 1 month, 6 months or 10 months post switch.

Results

Male mice dietary switched from AL-DR in mid life adopted the metabolic phenotype of mice exposed to DR from early life, so by the 10-month timepoint the AL-DR mice overlapped significantly with the DR mice in terms of their metabolic phenotype. Those animals switched from DR-AL in mid life showed clear evidence of a glycemic memory, with significantly improved glucose tolerance relative to mice maintained exclusively on AL feeding from early life. This difference in glucose tolerance was still apparent 10 months after the dietary switch, despite body mass, fasting insulin levels and insulin sensitivity all being similar to AL mice at this time.

Conclusions

Male C57BL/6 mice retain a long-term glycemic memory of early-life DR, in that glucose tolerance is enhanced in mice switched from DR-AL in mid life, relative to AL mice, even 10 months following the dietary switch. These data therefore indicate that the phenotypic benefits of DR are not completely dissipated following a return to AL feeding. The challenge now is to understand the molecular mechanisms underlying these effects, the time course of these effects and whether similar interventions can confer comparable benefits in humans.

Very-low-energy diets and morbidity: a systematic review of longer-term evidence

Evidence from the literature supports the safe use of very-low-energy diets (VLED) for up to 3 months in supervised conditions for patients who fail to meet a target weight loss using a standard low-fat, reduced-energy approach. There is, however, a need for longer-term outcomes on obesity and associated morbidities following a VLED. The present systematic review aims to investigate longer-term outcomes from studies using VLED, with a minimum duration of 12 months, published between January 2000 and December 2010. Studies conducted in both children and adults, with a mean/median BMI of ≥ 28 kg/m2 were included. PubMed, MEDLINE, Web of Science and Science Direct were searched. Reference lists of studies and reviews were manually searched. Weight loss or prevention of weight gain and morbidities were the main outcomes assessed. A total of thirty-two out of 894 articles met the inclusion criteria. The duration of the studies ranged from 12 months to 5 years. Periods of VLED ranged from 25 d to 9 months. Several studies incorporated aspects of behaviour therapy, exercise, low-fat diets, low-carbohydrate diets or medication. Current evidence demonstrates significant weight loss and improvements in blood pressure, waist circumference and lipid profile in the longer term following a VLED. Interpretation of the results, however, was restricted and conclusions with which to guide best practice are limited due to heterogeneity between the studies. The present review clearly identifies the need for more evidence and standardised studies to assess the longer-term benefits from weight loss achieved using VLED.

Less fat reduction per unit weight loss in type 2 diabetic compared with nondiabetic obese individuals completing a very-low-calorie diet program

The objective was to compare weight loss and change in body composition in obese subjects with and without type 2 diabetes mellitus during a very-low-calorie diet (VLCD) program. Seventy weight-matched subjects with diabetes or normal fasting glucose (controls) participated in a 24-week VLCD study. Primary end points were changes in anthropometry, body composition, and fasting plasma insulin and β-hydroxybutyrate concentrations. Fifty-one subjects (24 with diabetes) completed the study. No difference in weight loss between the 2 groups at 24 weeks was found by intention-to-treat analysis. Both groups completing the study per protocol had near-identical weight change during the program, with similar weight loss at 24 weeks (diabetes: 8.5 ± 1.3 kg vs control: 9.4 ± 1.2 kg, P = .64). Change in fat mass index correlated with change in body mass index (BMI) in both groups (diabetes: r = 0.878, control: r = 0.920, both P < .001); but change in fat mass index per unit change in BMI was less in the diabetic group compared with controls (0.574 vs 0.905 decrease, P = .003), which persisted after adjusting for age, sex, and baseline BMI (P = .008). Insulin concentrations remained higher and peak β-hydroxybutyrate concentrations were lower in the diabetic compared with the control group. While following a 24-week VLCD program, obese subjects with and without diabetes achieved comparable weight loss; but the decrease in adiposity per unit weight loss was attenuated in diabetic subjects. Hyperinsulinemia may have inhibited lipolysis in the diabetic group; however, further investigation into other factors is needed.

Effects of the modified linggui zhugan decoction (see text) combined with short-term very low calorie diets on glycemic control in newly diagnosed type 2 diabetics

OBJECTIVE

To evaluate the effects of the modified Linggui Zhugan Decoction (see text) combined with short-term very low calorie diets (VLCDs) on glycemic control in newly diagnosed type 2 diabetes mellitus (T2DM) patients.

METHODS

A total of 20 subjects with newly diagnosed T2DM were treated with the modified Linggui Zhugan Decoction (one-month administration) combined with short-term VLCDs (5 days), and 3-months follow-up. A standard 75-g oral-glucose-tolerance test (OGTT) indexes fasting plasma glucose (FPG), post-prandial 0.5 h and 2 h plasma glucose (P0.5hPG, P2hPG), glycated hemoglobin A(1c) (GHbA(1c)), body weight, body mass index (BMI), insulin function, insulin resistance index, incidence of hypoglycemia, and the liver and renal functions were evaluated before and after treatment. Correlations of BMI with insulin function and insulin resistance were also assessed.

RESULTS

After the treatment, the patients' plasma glucose decreased steadily, FPG decreased from 5.8 +/- 0.9 mmol/L at pre-treatment to 5.0 +/- 0.6 mmol/L at 3-months follow-up (P < 0.05), and P2hPG decreased from 11.7 +/- 3.8 mmol/L at pre-treatment to 6.9 +/- 0.9 mmol/L at 3-months follow-up (P < 0.01). The level of GHbA(1c) declined from (6.47 +/- 1.24)% at pre-treatment to (6.14 +/- 0.99)% at 3-months follow-up (P < 0.01). Body weight and BMI also declined significantly. Insulin resistance index was improved obviously and no event of hypoglycemia occurred. Part of the patients companied with fatty liver had a transient increase in hepatic transaminase during the treatment, but it turned to normal after the treatment.

CONCLUSIONS

The modified Linggui Zhugan Decoction combined with short-term VLCDs can be safely implemented for steady glycemic control in newly diagnosed T2DM patients.

Effects of a low-energy diet on sexual function and lower urinary tract symptoms in obese men

OBJECTIVE

Abdominal obesity and type 2 diabetes mellitus are associated with erectile and urinary dysfunction in men. The extent to which sexual function and lower urinary tract symptoms (LUTSs) are improved by weight loss remains unclear.

SUBJECTS

We compared the effects of 8 weeks of a low-calorie diet using meal replacements (Kicstart) on insulin sensitivity, plasma testosterone levels, erectile function (measured by the five-item version of the International Index of Erectile Function, IIEF-5), sexual desire (measured by the Sexual Desire Inventory, SDI) and LUTS (measured by the International Prostate Symptom Score, IPSS), in abdominally obese (body mass index >or=30 kg m(-2), waist circumference (WC) >or=102 cm) men (mean age 49.7 years) with uncomplicated diet or oral hypoglycemic-treated type 2 diabetes mellitus (n = 19) or without type 2 diabetes mellitus (n=25), with a control group of nondiabetic men (n = 26) with similar body mass index and WC.

RESULTS

Weight loss of ∼ 10% was significantly associated with increased insulin sensitivity, plasma testosterone levels, IIEF-5 and SDI scores, as well as reduced WC and IPSS scores, in diabetic as well as nondiabetic men. The degree of weight loss was significantly associated with improvements in plasma testosterone levels (r = -0.34), erectile function (r = -0.26) and LUTS (r=0.65). Reduction in LUTS was significantly associated with increased plasma testosterone (r = -0.35), erectile function (r = -0.42) and sexual desire (r = -0.40).

CONCLUSIONS

Diet-induced weight loss significantly and rapidly improves sexual function, and reduces LUTS, in obese middle-aged men with or without diabetes.

Effects and clinical potential of very-low-calorie diets (VLCDs) in type 2 diabetes

A recent study has shown that obese patients with newly diagnosed type 2 diabetes who lose 10% of their body weight are more likely to achieve glycaemic and blood pressure targets, despite weight regain. A well-established non-surgical method for achieving weight loss >or=10% within 3 months is the use of very-low-calorie diets (VLCDs). In patients with diabetes, VLCDs are associated with rapid improvement in glycaemia and cardiovascular risk factors. The present review analyses the evidence from available trials on the effects of VLCDs on body weight, glycaemic control and complications, and their potential for clinical use in diabetes management.

Attenuation of plasma dyslipidemia and oxidative damage by dietary caloric restriction in streptozotocin-induced diabetic rats

Oxidative stress has been proposed as the pathogenic mechanism linking insulin resistance with endothelial dysfunction during diabetes. The present study investigated the attenuation of plasma dyslipidemia and oxidative damage by caloric restriction in experimental diabetes. Forty male Wistar rats were divided into ad libitum and calorie-restricted groups. The calorie-restricted group was subjected to 30% caloric restriction for 63 days before induction of diabetes to 50% of both groups. Caloric restriction significantly (p<0.01) reduced the body weights, reactive oxygen species (ROS), catalase, total cholesterol levels and non-significantly reduced SOD activities in non-diabetic and diabetic rats. Caloric restriction was also found to improve blood glucose levels, glycated hemoglobin, malondialdehyde, triglyceride, oxidized glutathione and reduced glutathione levels and significantly (p<0.05) increased GPx and GR activities in the experimental animals. The non-diabetic rats fed ad libitum had the most significant increases in body weight which could be due to dyslipidemia. These results indicate that dietary caloric restriction attenuates the oxidative damage and dyslipidemia exacerbated during diabetes as evidenced by the significant reduction in their body weights, ROS, total cholesterol levels and the increases in GPx activity and redox status.

Dietary advice for treatment of type 2 diabetes mellitus in adults

BACKGROUND

While initial dietary management immediately after formal diagnosis is an 'accepted' cornerstone of treatment of type 2 diabetes mellitus, a formal and systematic overview of its efficacy and method of delivery is not currently available.

OBJECTIVES

To assess the effects of type and frequency of different types of dietary advice for adults with type 2 diabetes.

SEARCH STRATEGY

We carried out a comprehensive search of The Cochrane Library, MEDLINE, EMBASE, CINAHL, AMED, bibliographies and contacted relevant experts.

SELECTION CRITERIA

All randomised controlled trials, of six months or longer, in which dietary advice was the main intervention.

DATA COLLECTION AND ANALYSIS

The lead investigator performed all data extraction and quality scoring with duplication being carried out by one of the other six investigators independently with discrepancies resolved by discussion and consensus. Authors were contacted for missing data.

MAIN RESULTS

Thirty-six articles reporting a total of eighteen trials following 1467 participants were included. Dietary approaches assessed in this review were low-fat/high-carbohydrate diets, high-fat/low-carbohydrate diets, low-calorie (1000 kcal per day) and very-low-calorie (500 kcal per day) diets and modified fat diets. Two trials compared the American Diabetes Association exchange diet with a standard reduced fat diet and five studies assessed low-fat diets versus moderate fat or low-carbohydrate diets. Two studies assessed the effect of a very-low-calorie diet versus a low-calorie diet. Six studies compared dietary advice with dietary advice plus exercise and three other studies assessed dietary advice versus dietary advice plus behavioural approaches. The studies all measured weight and measures of glycaemic control although not all studies reported these in the articles published. Other outcomes which were measured in these studies included mortality, blood pressure, serum cholesterol (including LDL and HDL cholesterol), serum triglycerides, maximal exercise capacity and compliance. The results suggest that adoption of regular exercise is a good way to promote better glycaemic control in type 2 diabetic patients, however all of these studies were at high risk of bias.

AUTHORS' CONCLUSIONS

There are no high quality data on the efficacy of the dietary treatment of type 2 diabetes, however the data available indicate that the adoption of exercise appears to improve glycated haemoglobin at six and twelve months in people with type 2 diabetes. There is an urgent need for well-designed studies which examine a range of interventions, at various points during follow-up, although there is a promising study currently underway.

Screening candidate longevity therapeutics using gene-expression arrays

BACKGROUND

We review studies showing that CR acts rapidly, even in late adulthood, to extend health- and lifespan in mice. These rapid physiological effects are closely linked to patterns of gene expression in liver and heart. Non-human primate and human studies suggest that the signal transduction pathways responsible for the lifespan and health effects of caloric restriction (CR) may also be involved in human longevity. Thus, pharmaceuticals capable of mimicking the effects of CR (and other methods of lifespan extension) may have application to human health.

OBJECTIVE

We show that lifespan studies are an inefficient and theoretically problematic way of screening for longevity therapeutics. We review studies suggesting that rapid changes in patterns of gene expression can be used to identify pharmaceuticals capable of mimicking some positive effects of caloric restriction.

RESULTS

We present a traditional study of the effects of melatonin, melatonin and pregnenolone, aminoguanidine, aminoguanidine and alpha-lipoic acid, aminoguanidine, alpha-lipoic acid, pregnenolone, and coenzyme-Q(10) on the lifespan of mice. No treatment extended lifespan. However, because the mice die mostly of cancer, only chemopreventives active against specific cancers can be identified by such studies. The studies were also time-consuming and expensive. We discuss high-density microarray studies of the effectiveness of glucoregulatory drugs and putative cancer chemopreventatives at reproducing the hepatic gene-expression profiles of long-term and short-term CR. We describe the identification of one compound, metformin, which reproduces a subset of the gene-expression and physiological effects of CR.

CONCLUSION

Taken together, our results suggest that gene-expression biomarkers may be superior to lifespan studies for initial screening of candidate longevity therapeutics.

Exenatide and biotin in conjunction with a protein-sparing fast for normalization of beta cell function in type 2 diabetics

The dysdifferentiation of beta cells in type 2 diabetes appears to be caused and maintained by a vicious cycle of glucolipotoxicity: chronic elevations of glucose and free fatty acids induce beta cell dysdifferentiation as well as apoptosis; the resulting failure of glucose-stimulated insulin secretion tends to maintain the elevations of glucose and free fatty acids. Since extended fasts restore normoglycemia in diabetics, the resulting relief from glucotoxicity has been associated with a marked improvement in beta cell function that can be conserved after the fast if the factors precipitating diabetes--obesity, fatty and high-glycemic-index diets, sedentary lifestyle--have been adequately addressed. The new drug exenatide, an analog of the incretin hormone glucagon-like peptide-1, may be a worthwhile adjuvant to such fasting therapy, since it tends to counteract the glucolipotoxicity-induced down-regulation of the crucially important beta cell transcription factor IDX-1. Exenatide also exerts trophic effects on beta cell mass that in the longer term might help to restore diminished beta cell mass. Supraphysiological concentrations of biotin, possibly because they activate the soluble guanylate cyclase, also promote induction of IDX-1 and counteract the adverse impact of glucolipotoxicity in this regard; thus, high-dose biotin, which is well tolerated, may represent an additional adjuvant for therapeutic fasting intended to normalize beta cell function in type 2 diabetics.

Gene expression and physiologic responses of the heart to the initiation and withdrawal of caloric restriction

Aging increases and caloric restriction (CR) decreases morbidity and mortality associated with the cardiovascular system. Using Affymetrix microarrays, we identified changes in heart gene expression induced by aging and CR in male mice. Eight weeks of CR (CR8) reproduced 19% of the long-term CR (LTCR)-related expression changes. Because CR8 begins to extend the life span of these mice, these genes may be keys to its cardioprotective effects. CR8 and LTCR changed gene expression in a manner consistent with reduced remodeling and fibrosis, and enhanced contractility and energy production via lipid beta-oxidation. Molecular and histochemical studies indicated that CR reduced natriuretic peptide precursor type B and collagen expression, and reduced perivascular collagen deposition. We found smaller cardiomyocytes in the left ventricle of old-LTCR mice, suggesting reduced age-related cell death. Eight weeks of control feeding returned 97% of the LTCR-responsive genes to control expression levels. Thus, key CR-induced effects are rapidly responsive to diet, suggesting reduced caloric intake has rapid, positive effects on the heart.

Rapid and reversible induction of the longevity, anticancer and genomic effects of caloric restriction

It is widely held that caloric restriction (CR) extends lifespan by preventing or reducing the age-related accumulation of irreversible molecular damage. In contrast, our results suggest that CR can act rapidly to begin life and health span extension, and that its rapid genomic effects are closely linked to its health effects. We found that CR begins to extend lifespan and reduce cancer as a cause of death within 8 weeks in older mice, apparently by reducing the rate of tumor growth. Further, 8 weeks of CR progressively reproduces nearly three quarters of the genomic effects of long-term CR (LTCR) in liver. Fewer of the genomic effects of LTCR are rapidly reproduced by the initiation of CR in the heart, but the changes produced are keys to cardiovascular health. Thus, the genomic effects of CR may be established more rapidly in mitotic than in postmitotic tissues. Most of the genomic effects of LTCR dissipate 8 weeks after switching to a control diet. Consistent with these results, others have shown that acute CR rapidly and reversibly reduces the short-term risk of death in Drosophila to that of LTCR treated flies. Further, in late adulthood, acute CR partially or completely reverses age-related alterations of liver, brain and heart proteins. CR also rapidly and reversibly mitigates biomarkers of aging in adult rhesus macaques and humans. These data argue that highly conserved mechanisms for the rapid and reversible enhancement of life- and health-span exist for mitotic and postmitotic tissues.

Factors predicting the blood glucose lowering effect of a 30-day very low calorie diet in obese Type 2 diabetic patients

OBJECTIVE

To identify factors which predict the blood glucose lowering effect of monotherapy with a 30-day very low calorie diet (VLCD) in obese Type 2 diabetic patients. A responder was a priori defined as a patient with a fasting plasma glucose (FPG) level < 10 mmol/l on day 30.

RESEARCH DESIGN AND METHODS

In 17 obese patients (BMI 37.6 +/- 5.6 (mean +/- SD) kg/m(2)) with Type 2 diabetes, all blood glucose lowering medication (including insulin) was discontinued on day -1 followed by a 30-day VLCD. On day 2 and 30 of the VLCD an intravenous glucose tolerance test (IVGTT) was performed.

RESULTS

Of the 14 patients who completed the 30-day VLCD, eight qualified as responder. Responders and non-responders could be distinguished by day 2. Responders had a shorter duration of Type 2 diabetes and higher fasting serum insulin, C-peptide and HOMA-beta-values. In addition, responders displayed a more prominent second-phase insulin response following i.v. glucose loading and higher k-values. In a stepwise discriminant analysis, the change in FPG from day 0 to day 2 (responders +0.64 +/- 2.3, non-responders +4.15 +/- 3.3 mmol/l, P = 0.035) in combination with the area under the curve of insulin (AUC) above baseline during an IVGTT on day 2 (responders 571 +/- 236, non-responders 88 +/- 65 mU*50 min, P < 0.001), distinguished responders completely from non-responders.

CONCLUSION

Preservation of the capacity of beta-cells to secrete insulin predicts a favourable metabolic response to a VLCD in obese Type 2 diabetic patients.

The effects of dietary caloric restriction on antioxidant status and lipid peroxidation in mild and severe streptozotocin-induced diabetic rats

BACKGROUND

Dietary caloric restriction (CR) without malnutrition is effective in the control of diabetes mellitus by stabilizing glucose homeostasis and enhancing glycemic control. Mild and severe streptozotocin-induced diabetic and non-diabetic rats were subjected to caloric restriction and ad libitum feeding to evaluate their effects on oxidative stress and lipid profile in the plasma of experimental animals.

METHODS

Mild and severe diabetes were induced in Male Wistar rats by intraperitoneal injection of 35 and 65 mg/kg streptozotocin respectively. The experimental animals were subjected to 40% caloric restriction and ad libitum feeding for 9 weeks.

RESULTS

CR was effective in significantly reducing body weight, blood glucose, HbA IC and TG concentrations (all p < 0.001) in mild diabetic rats and non-significantly improving the plasma HDL-cholesterol concentrations. However, CR did not produce any significant effect on the antioxidant enzyme activities and MDA concentrations in all the groups nor in any of the parameters measured in non-diabetic rats except their overall weight change. There were significant (p < 0.001) decreases in body weight and non-significant fluctuating results in HbA IC and HDL-cholesterol in severe diabetic animals.

CONCLUSIONS

These results demonstrate that caloric restriction is most effective in mild than in non-diabetic or severe diabetic animals.

Current status of bariatric surgery in the treatment of type 2 diabetes

Bariatric surgery (from the Greek words baros meaning 'weight' and iatrikos 'the art of healing') is a rapidly evolving branch of surgical science. The aim is to induce major weight loss in those whose obesity places them at high risk of serious health problems. In an attempt to balance the risks of surgery against the benefits of weight loss, bariatric operations are currently performed only in the morbidly obese, or those with a body mass index (BMI) > 35 kgm(-2) who already have developed comorbidity such as type 2 diabetes. Although weight loss is beneficial for obese patients with diabetes, current medical treatment for obesity is difficult. In contrast, observational studies show a major impact of bariatric surgery on diabetes, raising the question whether this approach should be used more widely to treat diabetes in obese patients? If bariatric surgery were shown to be the best way to treat diabetes in obese subjects the implications for health services would be wide-ranging. Bariatric surgery leads to withdrawal of diabetic treatment in about 60% or more of patients, and reductions of therapy for many others. Although data on bariatric surgery in subjects with diabetes are provocative, most studies have been uncontrolled or flawed in other ways. Most importantly, bariatric surgery has not yet been compared against standard medical treatment for diabetes in randomized controlled trials with diabetes-specific endpoints in all relevant patient groups. Potential indications for bariatric surgery are discussed, and the unanswered questions that need to be addressed by clinical trials are summarized. Although small numbers of patients may be interested in bariatric surgery for type 2 diabetes, current data are insufficient to endorse its wide scale use for this indication. Until essential studies are undertaken the role and economics of bariatric surgery in the diabetic clinic will remain uncertain.

Treatment of type 2 diabetes in childhood using a very-low-calorie diet

OBJECTIVE

Pharmacologic agents currently approved for use in children with type 2 diabetes (metformin and insulin) are less than optimal for some patients. We evaluated the use of a ketogenic, very-low-calorie diet (VLCD) in the treatment of type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a chart review of 20 children (mean age 14.5 +/- 0.4 years) who consumed a ketogenic VLCD in the treatment of type 2 diabetes. Several response variables (BMI, blood pressure, HbA(1c), blood glucose, and treatment regimens) were examined before, during, and up to 2 years after the diet and compared with a matched diabetic control group.

RESULTS

Before starting the diet, 11 of 20 patients were treated with insulin and 6 with metformin. Mean daily blood glucose values fell from 8.9 +/- 1.1 to 5.5 +/- 0.38 mmol/l (P < 0.0001) in the first 3 days of the VLCD, allowing insulin and oral agents to be discontinued in all but one subject. BMI fell from 43.5 +/- 1.8 to 39.3 +/- 1.8 kg/m(2) (P < 0.0001) and HbA(1c) dropped from 8.8 +/- 0.6 to 7.4 +/- 0.6% (P < 0.005) as the diet was continued for a mean of 60 +/- 8 days (range 4-130 days), and none required resumption of antidiabetic medications. Sustained decreases in BMI and insulin requirements were observed in patients remaining on the VLCD for at least 6 weeks when compared with those of the control group.

CONCLUSIONS

The ketogenic VLCD is an effective short-term, and possibly long-term, therapy for pediatric patients with type 2 diabetes. Blood glucose control and BMI improve, allowing the discontinuation of exogenous insulin and other antidiabetic agents. This diet, although strict, has potential as an alternative to pharmacologic therapies for this emerging subset of diabetic individuals.

The effect of a rapid weight loss on lipid profile and glycemic control in obese type 2 diabetic patients

OBJECTIVE

To test the effect of low calorie diet (LCD) on body weight, lipid profile, and glycemic control in obese type 2 diabetes mellitus (DM) patients.

DESIGN

Dietary intervention.

SETTING

Department of Human Nutrition, Copenhagen.

SUBJECTS

Outpatients: 11 type 2 DM patients (three males/eight females) (10 completed), four on oral hypoglycemic agents (OHA). Body mass index (BMI) 36.8 +/- 5.5 kg/m2 and age 62 +/- 5.7 y.

INTERVENTIONS

In all, 8 weeks full meal-replacement diet: eight sachets of a nutrition powder (Nutrilett, 850 kcal/day). Lipid profile assessed by NMR spectroscopy.

RESULTS

Mean body weight fell by 10.9 kg (approximately 11%, P<0.001). Fasting insulin, fasting blood glucose, hemoglobin A1c, fasting plasma triglycerides, total cholesterol, and low-density lipoprotein (LDL) cholesterol fell significantly. There were large positive changes (statistically insignificant) in LDL subclass distribution and a similar shift in high-density lipoprotein subclass distribution. Medication was discontinued in all four subjects taking OHA for 2 weeks prior to the intervention and throughout the whole 8-week intervention period.

CONCLUSION

LCD is effective in improving glycemic control and blood lipids through weight loss in overweight type 2 DM patients.

Metabolic and cardiovascular effects of very-low-calorie diet therapy in obese patients with Type 2 diabetes in secondary failure: outcomes after 1 year

AIMS

To evaluate the short-term and 1-year outcomes of an intensive very-low-calorie diet (VLCD) on metabolic and cardiovascular variables in obese patients with Type 2 diabetes (T2DM) and symptomatic hyperglycaemia despite combination oral anti-diabetic therapy +/- insulin, and to assess patient acceptability and the feasibility of administering VLCD treatment to this subgroup of patients in a routine practice setting.

METHODS

Forty obese patients with T2DM (22 M, mean age 52 years, body mass index (BMI) 40 kg/m2, duration of T2DM 6.1 years) and symptomatic hyperglycaemia despite combination oral therapy (n = 26) or insulin + metformin (n = 14) received 8 weeks of VLCD therapy (750 kcal/day) followed by standard diet and exercise advice at 2-3-month intervals up to 1 year. Insulin was discontinued at the start of the VLCD, and anti-diabetic therapy was adjusted individually throughout the study, including (re)commencement of insulin as required.

RESULTS

Immediate improvements in symptoms and early weight loss reinforced good compliance and patient satisfaction. After 8 weeks of VLCD, body weight and BMI had fallen significantly: 119 +/- 19-107 +/- 18 kg and 40.6-36.6 kg/m2, respectively, with favourable reductions in serum total cholesterol (5.9-4.9 mm), blood pressure (10/6 mmHg) and fructosamine (386 +/- 73-346 +/- 49 microm) (equates to an HbA1c reduction of approximately 1%). Sustained improvements were evident after 1 year, with minimal weight regain, e.g. mean body weight 109 +/- 18 kg and BMI 37 +/- 4 kg/m2. Glycaemic control tended to deteriorate after 1 year.

CONCLUSIONS

The absence of a control group is a major limitation, but the results indicate that 8 weeks of VLCD treatment may be effective and well tolerated in symptomatic obese patients with T2DM in secondary failure, producing sustained cardiovascular and metabolic improvements after 1 year. VLCD therapy is a treatment option that deserves greater consideration in this difficult-to-treat patient population.

Incorporation of beta cell redifferentiation therapy into a lipoprivic strategy for reversing type 2 diabetes

Type 2 diabetes (non-insulin-dependent diabetes mellitus, NIDDM), at least in the majority of patients characterized by insulin resistance and increased visceral fat, appears to be precipitated by the exposure of tissues to excessive levels of free fatty acids; this can contribute to the muscle insulin resistance, excessive hepatic gluconeogenesis, and beta cell dysfunction that collaborate to impair glycemic control. The resultant hyperglycemia, in turn, exacerbates the insulin resistance and beta cells dysfunction. The failure of glucose-stimulated insulin secretion (GSIS) in beta cells helps to sustain the elevations of serum glucose and free fatty acids, which in turn reinforce the failure of GSIS, possibly by inhibiting expression of the transcription factor IDX-1; NIDDM thus represents a vicious cycle that is not easily broken. A new strategy for achieving rapid loss of body fat - hepatothermic therapy (HT), an integrated approach involving exercise training, low-fat, low-glycemic-index food choices, and a supplementation program that promotes hepatic fatty acid oxidation - shows promise for alleviating the excessive fat exposure at the root of the diabetic syndrome, as well as the underlying insulin resistance syndrome responsible for increased macrovascular risk. However, when HT proves incapable of breaking the vicious cycle sustaining beta cell dysfunction, a supplementary strategy, beta cell redifferentiation therapy (BRT), may be required. BRT consists of a protocol in which near-normoglycemia is maintained for several weeks through use of intensive insulin therapy (e.g. artificial pancreas) or other effective measures, during which time beta cell GSIS can be expected to substantially recover owing to relief from glucolipotoxicity. Clinical experience demonstrates that this improved beta cell function, in certain cases, can persist for months or years after temporary BRT. A portion of the improved glycemic control achieved with very low calorie diets in NIDDM is reflective of improved GSIS, presumably consequent to a sustained reduction in diurnal glycemia. Long-lived analogs of glucagon-like peptide-1 (GLP-1) may find a key role in BRT; this incretin hormone not only potentiates GSIS, but also appears to increase the expression and activity of IDX-1 in beta cells, thus promoting beta cell redifferentiation. If HT is instituted prior to and following BRT to alleviate the FFA overexposure that initially precipitated the diabetic syndrome, it seems likely that the benefits of BRT will be conserved in the long term, thus enabling a reversal of NIDDM - in other words, maintenance of normoglycemia without medication. Since NIDDM is inherently preventable, its reversal should be the fundamental goal of diabetes therapy.

Caloric restriction mimetics: metabolic interventions

Caloric restriction (CR) retards diseases and aging in laboratory rodents and is now being tested in nonhuman primates. One way to apply these findings to human health is to identify and test agents that may mimic critical actions of CR. Panel 2 focused on two outcomes of CR, reduction of oxidative stress and improved glucoregulation, for which candidate metabolic mimics exist. It was recommended that studies on oxidative stress should emphasize mitochondrial function and to test the efficacy of nitrone and other antioxidants in mimicking CR's effects. Studies should also focus on the long-term effects of compounds known to lower circulating glucose and insulin concentrations or to increase insulin sensitivity. Also, four other developing areas were identified: intermediary metabolism, response to infection, stress responses, and source of dietary fat. These areas are important because either they hold promise for the discovery of new mimetics or they need to be explored prior to initiation of CR trials in humans. Other recommendations were that transgenic approaches and adult-onset CR should be emphasized in future studies.

Diabetes disease stage predicts weight loss outcomes with long-term appetite suppressants

OBJECTIVES

Characterize degree of weight loss with stage of diabetes and describe its effect on cardiovascular disease risk factors in obese patients with and without diabetes.

RESEARCH METHODS AND PROCEDURES

Retrospective cohort analysis from patients participating in a long-term weight management protocol using diet, exercise, behavioral modification, and appetite-suppressant therapy. Patient groups, with (n = 19) and without diabetes (n = 19) were matched for age, gender, and weight before weight loss therapy. The effect of 12 months of therapy on weight, blood pressure, glycemic control, lipid profile, and medication requirements were tested. Additionally, patients were grouped or staged based upon therapy required for control of diabetes at the beginning of weight loss intervention. Analysis of covariance described relationships between diabetes disease stage and weight loss at 12 months.

RESULTS

Nondiabetic patients had greater mean reduction in BMI than the diabetic group (7.98 kg/m2 vs. 4.77 kg/m2, p<0.01). A significant linear trend (p<0.001) for decreasing weight loss with stage of diabetes was observed. Blood pressure, lipid profile, and glycemia improved significantly. The average daily glyburide-equivalent dose decreased from 9.4 to 3.0 mg (p<0.01).

DISCUSSION

Patients with diabetes lost less weight than similarly obese patients without diabetes. Regardless of differential weight loss between groups, cardiovascular disease risk factors improved. Hypoglycemic medication requirements decreased with weight loss therapy. A predictive relationship may exist between diabetes disease stage before weight loss therapy and future weight loss potential.