A critical review of low-carbohydrate diets in people with Type 2 diabetes

Structural Concepts, Definition, Classification, and Macronutrient and Food Composition of Carbohydrate-Restricted Diets for Individuals with Type 2 Diabetes Mellitus: A Scoping Review

Objective: This study aimed to review the structural concepts, definition, classification, and macronutrient and food composition of carbohydrate-restricted diets (CRDs) for individuals with type 2 diabetes mellitus (T2DM). Methods: A scoping review was conducted following Joanna Briggs Institute guidelines. Searches were performed in Scopus, PubMed, Web of Science, and Embase, including texts published in Portuguese, English, and Spanish. Official documents from governments, regulatory agencies, and international diabetes organizations were also consulted. Results: In total, 79 articles and 17 official documents were analyzed. The following structural concept was identified: restricted carbohydrate intake decreases the need for endogenous and exogenous insulin, contributing to the maintenance of glycemic control, and justifies its consideration among the nutritional therapy options for individuals with T2DM. CRDs varied in definition, classification, and macronutrient composition. Studies failed to provide detailed information on the food composition of diets, precluding an in-depth understanding of metabolic effects. The existence of several approaches with varying recommendations makes it difficult to generalize the results. International CRD guidelines for T2DM adopt divergent definitions, compromising interpretation, recommendation, and even adherence. Conclusions: Although the concept of CRDs justifies their adoption within the nutritional therapy choices for T2DM, the multiple denominations can hinder understanding and comparison between studies. The lack of information on food composition and carbohydrate types compromises the assessment of the effects and adherence to CRD-based nutritional interventions. We emphasize the need for methodologically consistent studies that evaluate CRDs based on fresh and minimally processed foods with a low glycemic index to support official diabetes guidelines and organizations.

Efficacy of long-term low carbohydrate diets for patients with type 2 diabetes: A systematic review and meta-analysis

AIMS/INTRODUCTION

Efficacy of long-term low-carbohydrate diets (LCD) to improve glycemic management for type 2 diabetes remains controversial. Thus, we investigated the association between long-term LCD and glycemic control in individuals with type 2 diabetes.

MATERIALS AND METHODS

We searched PubMed, Embase and the Cochrane Database for articles published up to June 2023, and included randomized controlled trials conducted on LCD interventions for >12 months in adults with type 2 diabetes. Primary outcome was the difference in glycated hemoglobin between long-term LCD and control groups. Additionally, we evaluated the differences in changes in systolic and diastolic blood pressure, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, and weight between long-term LCD and control groups.

RESULTS

Six studies were identified and met the inclusion criteria. This study did not show significant differences in changes in glycated hemoglobin between long-term LCD and control diets (standardized mean difference -0.11, 95% confidence interval -0.33 to 0.11, P = 0.32). As with glycemic control, there were no significant differences in the changes in weight loss, blood pressure, and low-density lipoprotein cholesterol between long-term LCD and control diets. However, long-term LCD were associated with greater elevation in high-density lipoprotein cholesterol (standardized mean difference 0.22, 95% confidence interval 0.04-0.41; P = 0.02) and decrease in triglyceride (standardized mean difference -0.19; 95% confidence interval -0.37 to 0.02; P = 0.03) than that in control diets.

CONCLUSIONS

Our findings suggest efficacy of long-term LCD in treating dyslipidemia in individuals with type 2 diabetes, but do not recommend long-term LCD for glycemic control in the individuals.

Very low-carbohydrate diet with higher protein ratio improves lipid metabolism and inflammation in rats with diet-induced nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is commonly associated with obesity, and it is mainly treated through lifestyle modifications. The very low-carbohydrate diet (VLCD) can help lose weight rapidly but the possible effects of extreme dietary patterns on lipid metabolism and inflammatory responses in individuals with NAFLD remain debatable. Moreover, VLCD protein content may affect its effectiveness in weight loss, steatosis, and inflammatory responses. Therefore, we investigated the effects of VLCDs with different protein contents in NAFLD rats and the mechanisms underlying these effects. After a 16-week inducing period, the rats received an isocaloric normal diet (NC group) or a VLCD with high or low protein content (NVLH vs. NVLL group, energy ratio:protein/carbohydrate/lipid=20/1/79 vs. 6/1/93) for the next 8 weeks experimental period. We noted that the body weight decreased in both the NVLH and NVLL groups; nevertheless, the NVLH group demonstrated improvements in ketosis. The NVLL group led to hepatic lipid accumulation, possibly by increasing very-low-density lipoprotein receptor (VLDLR) expression and elevating liver oxidative stress, subsequently activating the expression of Nrf2, and inflammation through the TLR4/TRIF/NLRP3 and TLR4/MyD88/NF-κB pathway. The NVLH was noted to prevent the changes in VLDLR and the TLR4-inflammasome pathway partially. The VLCD also reduced the diversity of gut microbiota and changed their composition. In conclusion, although low-protein VLCD consumption reduces BW, it may also lead to metabolic disorders and changes in microbiota composition; nevertheless, a VLCD with high protein content may partially alleviate these limitations.

The association between body weight indices, behavioral factors, and type 2 diabetes mellitus in Africa: A systematic review and meta-analysis of population-based epidemiological studies

BACKGROUND AND AIM

Type 2 diabetes mellitus (T2DM) is a significant public health concern in Africa. While the associations between modifiable risk factors and T2DM are likely to be Africa-specific, their overall estimations have not been published. This study aimed to use systematic and meta-analytic methods to examine the strength of associations between modifiable risk factors and T2DM in Africa.

METHODS AND RESULTS

A systematic search of literature published between January 2000 to March 2022 was conducted. The review included only population-based studies and data extracted from 57 studies. Of these, unadjusted data from 50 studies were included in meta-analysis. With considerable heterogeneity between studies, random-effect models were calculated to ascertain the odds ratios (OR) and 95% confidence intervals (CI) for the associations between obesity (OB) and overweight (OV), defined by BMI; central obesity (waist circumference (OB-WC), waist-to-hip-ratio (OB-WHR)), alcohol, fruit and vegetable consumption, smoking, physical activity (PA) and T2DM. Moderator effects of age, African regions, and urban/rural location were assessed. Risk factors associated with T2DM include BMI-OB [OR = 3.05, 95% CI: (2.58, 3.61)], BMI-OV [OR = 2.38, 95% CI: (1.51, 3.75)], and BMI-OV/OB [OR = 2.07, 95% CI: (1.82, 2.34)]; OB-WC [OR = 2.58, 95% CI: (2.09, 3.18)] and OB-WHR [OR = 2.22, 95% CI: (1.69, 2.92)]; PA [OR = 1.85, 95% CI: (1.50, 2.30)]. Significant moderator effects were not observed.

CONCLUSION

Obesity defined by BMI and central obesity, but not behavioral risk factors were most strongly associated with T2DM in African populations, emphasizing the need for obesity prevention to limit the rise of T2DM.

REGISTRATION

The PROSPERO registration number is CRD42016043027.

Behavioral approaches to nutrition and eating patterns for managing type 2 diabetes: A review

Nutritional interventions are a key component of type 2 diabetes management; making health-supporting changes in eating patterns can improve postprandial glycemic excursions and lower HbA1c to reduce diabetes-related morbidity and mortality. Research around implementing calorie-restricted and/or low-carbohydrate diets is plentiful, though the ability to sustain physiologic and behavioral changes for longer than 12 months is a concern. An understanding of intervention goals and adherence is needed to apply this research to patient care and translate expectations to real-world living contexts. Diverse dietary patterns including a Mediterranean eating pattern, vegetarian or plant-based eating pattern, or others that emphasize high-quality carbohydrates (e.g., whole grains), vegetables, whole fruits, legumes, and fish can support achievement of glycemic targets. Counseling strategies like motivational interviewing can be used to build eating competence. These approaches prioritize collaborative decision-making with the goal of increasing patient empowerment and self-efficacy. Strategies for incorporating these tools and frameworks in a clinical setting are highlighted. Providing ongoing diabetes and nutrition education, paired with appropriate support to address the challenges in implementing and sustaining behavior changes, is warranted. Further, social determinants of health including environmental context, education, socioeconomic status, access to healthcare, and experiences of systemic stigma (e.g., racism or weight bias) can interfere with individuals' diabetes self-care and nutrition behaviors. Providing medical nutrition therapy and tailoring nutrition interventions to individual needs and circumstances can be an important way physicians, dietitians, and diabetes providers can support individuals with type 2 diabetes.

Effect of aerobic exercise and low-carbohydrate high-fat diet on glucose tolerance and android/gynoid fat in overweight/obese women: A randomized controlled trial

The study was designed to compare the effects of weight loss induced by a low-carbohydrate-high-fat diet or a normal diet, with and without exercise, on glucose tolerance measured as area under the curve (AUC), and android (A) and gynoid (G) fat distribution. The study was registered at clinicaltrials.gov; NCT04100356. In total, 57 women classified as overweight or obese (age 40 ± 3.5 years, body mass index 31.1 ± 2.6 kg/m²) were randomly assigned and completed a 10-week intervention using a low-carbohydrate high-fat diet or a normal diet, with or without aerobic interval exercise. An equal deficit of 700 kcal/day was prescribed, either restricting the diet only, or moderately restricting diet and including three 50-min high-intensity bicycle sessions per week. There were thus four groups: normal diet (NORM); low-carbohydrate-high-fat diet (LCHF); normal diet with exercise (NORM-EX); and low-carbohydrate-high-fat diet with exercise (LCHF-EX). Linear mixed models was used to assess differences between groups. With all groups pooled, the intervention resulted in a weight loss of 6.7 ± 2.5% (p < 0.001). The intervention did not result in differences between groups in AUC glucose, nor in fasting glucose or indicis for insulin resistance such as Homeostatic Model Assessment, Matsuda Insulin Sensitivity Index, insulinogenic index and disposition index. Post-intervention android fat was lower in LCHF than NORM (3,223 ± 727 vs. 2,533 ± 535 g, p = 0.041). LCHF reached a lower A/G ratio than NORM (0.94 ± 0.12 vs. 1.04 ± 0.09, p = 0.011) and LCHF-EX (0.94 ± 0.12 vs. 1.09 ± 0.09, p < 0.001) after the intervention. LCHF resulted in lower android fat mass compared to NORM and the lowest A/G ratio compared to the other matched groups, but with no accompanying improvement in AUC glucose. In conclusion, although all groups achieved improvements in glucose tolerance, no superior effect was observed with the LCHF diet, neither with nor without exercise.

[Nutrition for diabetic patients (Update 2023)]

All patients with diabetes require individual and personalized nutritional consultation with professionals. The patient's needs should be the primary focus of the dietary therapy, taking their lifestyle and the type of diabetes into consideration. With the recommendations to the patient's diet, there need to be specific metabolic goals to reduce the disease's progression and to avoid long term health effects. Therefore, practical guidelines such as portion size and meal planning tips should be the main focus.According to the latest national and international standards, patients suffering from diabetes should have access to nutrition consulting and nutritional training. During consultation they can be supported on- how to manage their health condition and choosing food and beverage to improve their health.These practical recommendations sum up the latest literature on nutritional aspects of diabetes treatment.

Relationships Among Perception of Cognitive Function, Diabetes Self-Management, and Glucose Variability in Older Adults: A Mixed Methods Study

The aim of the current study was to explore relationships among perceived cognitive function, glucose variability, and self-management in older adults with type 2 diabetes mellitus (T2DM). A mixed methods design was used with data from: (a) questionnaires on perceived cognitive function and diabetes self-management; (b) continuous glucose monitoring (CGM) reports; and (c) semi-structured interviews. Thirty adults with T2DM (47% female; mean age = 68.5 [SD = 5.2] years) participated. Those who exercised more days per week had more stable glucose. Those who reported fewer days of diet adherence had more hypoglycemia. Participants who reported higher levels of memory dissatisfaction exhibited higher levels of glucose variability. Findings point to the potential of glucose variability as a target to reduce the effect of diabetes on cognitive function. Instruction in recognition of glucose patterns found via CGM can be integrated into self-management education to improve self-management and subsequent glucose control and cognitive function. [Research in Gerontological Nursing, xx(x), xx-xx.].

Behavioral Characteristics and Self-Reported Health Status among 2029 Adults Consuming a "Carnivore Diet"

BACKGROUND

The "carnivore diet," based on animal foods and excluding most or all plant foods, has attracted recent popular attention. However, little is known about the health effects and tolerability of this diet, and concerns for nutrient deficiencies and cardiovascular disease risk have been raised.

OBJECTIVES

We obtained descriptive data on the nutritional practices and health status of a large group of carnivore diet consumers.

METHODS

A social media survey was conducted 30 March-24 June, 2020 among adults self-identifying as consuming a carnivore diet for ≥6 mo. Survey questions interrogated motivation, dietary intake patterns, symptoms suggestive of nutritional deficiencies or other adverse effects, satisfaction, prior and current health conditions, anthropometrics, and laboratory data.

RESULTS

A total of 2029 respondents (median age: 44 y, 67% male) reported consuming a carnivore diet for 14 mo (IQR: 9-20 mo), motivated primarily by health reasons (93%). Red meat consumption was reported as daily or more often by 85%. Under 10% reported consuming vegetables, fruits, or grains more often than monthly, and 37% denied vitamin supplement use. Prevalence of adverse symptoms was low (<1% to 5.5%). Symptoms included gastrointestinal (3.1%-5.5%), muscular (0.3%-4.0%), and dermatologic (0.1%-1.9%). Participants reported high levels of satisfaction and improvements in overall health (95%), well-being (66%-91%), various medical conditions (48%-98%), and median [IQR] BMI (in kg/m2) (from 27.2 [23.5-31.9] to 24.3 [22.1-27.0]). Among a subset reporting current lipids, LDL-cholesterol was markedly elevated (172 mg/dL), whereas HDL-cholesterol (68 mg/dL) and triglycerides (68 mg/dL) were optimal. Participants with diabetes reported benefits including reductions in median [IQR] BMI (4.3 [1.4-7.2]), glycated hemoglobin (0.4% [0%-1.7%]), and diabetes medication use (84%-100%).

CONCLUSIONS

Contrary to common expectations, adults consuming a carnivore diet experienced few adverse effects and instead reported health benefits and high satisfaction. Cardiovascular disease risk factors were variably affected. The generalizability of these findings and the long-term effects of this dietary pattern require further study.

[The ketogenic diet: history, mechanism of action, indications and contraindications]

Low-carb diets have been successfully used to alleviate a number of severe neurological diseases for about 100 years. The publication of the results of new studies suggesting that this type of diet may play a therapeutic role in other pathologies such as diabetes, obesity, polycystic ovary syndrome, and oncology is of particular interest for both doctors and the public. However, the long-term safety of using a low-carb or ketogenic diet, as well as its impact, primarily on the risks of developing cardiovascular diseases, remains poorly studied. This article presents the results of observation of patients against the background of a low-carbohydrate diet, both in the short-term perspective as well as provides an assessment of its long-term consequences.

Association between low carbohydrate diet (LCD) and sleep quality by mediating role of inflammatory factors in women with overweight and obesity: A cross-sectional study

Poor sleep quality can lead to increased obesity. Low carbohydrate diet (LCD) is considered as an approach for sleep quality and obesity improvement. The aim of this investigation is to evaluate the relationship between LCD and sleep quality with the mediatory effect of inflammatory markers including transforming growth factor-β (TGF-β), high-sensitivity C-reactive protein (hs-CRP), total antioxidant capacity: In our cross-sectional study, 304 obese women aged from 19 to 50 years were enrolled. Body mass index (BMI) in these women ranged from 25.2 to 48.3 kg/m2. LCD score was assessed by a 147- item semi-quantitative food frequency questionnaire (FFQ). The Pittsburgh Sleep Quality Index (PSQI) was used to assess the sleep quality. FFQ and PSQI questionnaires are completed simultaneously by the participants. Biochemical indicators (inflammatory markers) were measured and anthropometric components were evaluated. The relationship between sleep quality and LCD with quantitative variables was assessed by independent sample t-test and with qualitative variables by chi-square test. Binary logistic regression was used to estimate confounding variables including age, job, stress, weight to investigate the relationship between LCD and sleep. Following of LCD had a significant negative relationship with PSQI score. It can be said that with increasing LCD adherence, the possibility of poor sleep quality decrease (OR = 0.43, 95% CI = 0.19-0.94,p = .03). It was also showed, hs-CRP (OR = 0.61, 95% CI = 0.3-1.21, p = .16) and TAC (OR = 0.6, 95% CI = 0.25-1.4, p = 0.24), eliminated the significance of the association and it is possible that they play a mediating role in this relationship Following the LCD can have a positive effect on improving PSQI scores by reduction in inflammatory markers levels.

Glycemic Control and Metabolic Adaptation in Response to High-Fat versus High-Carbohydrate Diets-Data from a Randomized Cross-Over Study in Healthy Subjects

Granular study of metabolic responses to alterations in the ratio of dietary macro-nutrients can enhance our understanding of how dietary modifications influence patients with impaired glycemic control. In order to study the effect of diets enriched in fat or carbohydrates, fifteen healthy, normal-weight volunteers received, in a cross-over design, and in a randomized unblinded order, two weeks of an iso-caloric high-fat diet (HFD: 60E% from fat) and a high-carbohydrate diet (HCD: 60E% from carbohydrates). A mixed meal test (MMT) was performed at the end of each dietary period to examine glucose clearance kinetics and insulin and incretin hormone levels, as well as plasma metabolomic profiles. The MMT induced almost identical glycemia and insulinemia following the HFD or HCD. GLP-1 levels were higher after the HFD vs. HCD, whereas GIP did not differ. The HFD, compared to the HCD, increased the levels of several metabolomic markers of risk for the development of insulin resistance, e.g., branched-chain amino acid (valine and leucine), creatine and α-hydroxybutyric acid levels. In normal-weight, healthy volunteers, two weeks of the HFD vs. HCD showed similar profiles of meal-induced glycemia and insulinemia. Despite this, the HFD showed a metabolomic pattern implying a risk for a metabolic shift towards impaired insulin sensitivity in the long run.

Carbohydrate restriction for diabetes: rediscovering centuries-old wisdom

Carbohydrate restriction, used since the 1700s to prolong survival in people with diabetes, fell out of favor after the discovery of insulin. Despite costly pharmacological and technological developments in the last few decades, current therapies do not achieve optimal outcomes, and most people with diabetes remain at high risk for micro- and macrovascular complications. Recently, low-carbohydrate diets have regained popularity, with preliminary evidence of benefit for body weight, postprandial hyperglycemia, hyperinsulinemia, and other cardiometabolic risk factors in type 2 diabetes and, with more limited data, in type 1 diabetes. High-quality, long-term trials are needed to assess safety concerns and determine whether this old dietary approach might help people with diabetes attain clinical targets more effectively, and at a lower cost, than conventional treatment.

Benefits of Low Carbohydrate Diets: a Settled Question or Still Controversial?

PURPOSE OF REVIEW

The purpose of this review was to provide an update on the available data on the benefits of low-carbohydrate (low-carb) diets for weight management and type 2 diabetes (T2DM) and determine if low-carb diets were a settled question or still controversial.

RECENT FINDINGS

Most of the recent published literature in this area consists of reviews of past trials, with a relatively smaller number of recent trials. Low-carb is most commonly compared to low-fat, with problematically inconsistent definitions of both. There are numerous challenges in trying to draw clear conclusions about efficacy and effectiveness. Short-term vs. long-term effects can differ, which is likely impacted by adherence. Adherence is very different between metabolic chamber or feeding studies vs. free-living. Body weight alone is a crude measure that fails to capture potentially important differences in lean-mass, fat-mass, and body water. Benefits for glycemic control need to be balanced with impacts on non-glycemic outcomes such as LDL-cholesterol, the microbiome, and inflammation. It is important to differentiate between low-carb and very-low carbohydrate diets (VLCD). To date no large-scale long-term clinical trials have been conducted testing whether low-carb diets can prevent T2DM. Many issues regarding benefits and risks of low-carb diets remain controversial or unresolved, particularly for VLCD. Some of the recent, better studies highlighted in this review suggest strategies for resolving these controversies.

Effects of Quality and Quantity of Protein Intake for Type 2 Diabetes Mellitus Prevention and Metabolic Control

PURPOSE OF REVIEW

The aim of this review is to evaluate the ideal protein quality and quantity and the dietary composition for the prevention and metabolic control of type 2 diabetes mellitus (T2DM).

INTRODUCTION

Although some reviews demonstrate the advantages of a diet with a higher protein intake, other reviews have observed that a diet high in carbohydrates, with low-glycaemic index carbohydrates and good fibre intake, is equally effective in improving insulin sensitivity.

METHODS

Over 2831 articles were screened, and 24 from the last 5 years were analysed and summarised for this review, using the protein, diabetes and insulin glucose metabolic keywords in Pubmed in June 2019.

RESULTS

Eleven studies demonstrate that a higher consumption of proteins has a positive effect on insulin sensitivity. A higher intake of animal protein seems to be related to an increased risk of T2DM. Four studies show that consumption of meat has a deleterious effect. Higher intake of plant protein and dairy products is associated with a modestly reduced risk.

DISCUSSION

Based on the results obtained, for the prevention of T2DM and all disorders related to metabolic syndrome, no ideal dietary composition has yet been found. The advantage of plant protein sources may be related to the foods' low-glycaemic index due to the high fibre content. However, the right protein quality (animal and plant) and the quantity for T2DM prevention and metabolic control are unclear and need to be investigated with further long-term studies.

Low Carbohydrate Dietary Approaches for People With Type 2 Diabetes-A Narrative Review

Although carbohydrate restriction is not a new approach for the management of Type 2 diabetes, interest in its safety and efficacy has increased significantly in recent years. The purpose of the current narrative review is to summarise the key relevant research and practical considerations in this area, as well as to explore some of the common concerns expressed in relation to the use of such approaches. There is a strong physiological rationale supporting the role of carbohydrate restriction for the management of Type 2 diabetes, and available evidence suggests that low carbohydrate dietary approaches (LCDs) are as effective as, or superior to, other dietary approaches for its management. Importantly, LCDs appear to be more effective than other dietary approaches for facilitating a reduction in the requirement for certain medications, which leads to their effects on other health markers being underestimated. LCDs have also been demonstrated to be an effective method for achieving remission of Type 2 diabetes for some people. The available evidence does not support concerns that LCDs increase the risk of cardiovascular disease, that such approaches increase the risk of nutrient deficiencies, or that they are more difficult to adhere to than other dietary approaches. A growing number of organisations support the use of LCDs as a suitable choice for individuals with Type 2 diabetes.

Type 2 diabetes and remission: practical management guided by pathophysiology

The twin cycle hypothesis postulated that type 2 diabetes was a result of excess liver fat causing excess supply of fat to the pancreas with resulting dysfunction of both organs. If this was so, the condition should be able to be returned to normal by calorie restriction. The Counterpoint study tested this prediction in short-duration type 2 diabetes and showed that liver glucose handling returned to normal within 7 days and that beta-cell function returned close to normal over 8 weeks. Subsequent studies have demonstrated the durability of remission from type 2 diabetes. Remarkably, during the first 12 months of remission, the maximum functional beta-cell mass returns completely to normal and remains so for at least 24 months, consistent with regain of insulin secretory function of beta cells which had dedifferentiated in the face of chronic nutrient oversupply. The likelihood of achieving remission after 15% weight loss has been shown to be mainly determined by the duration of diabetes, with responders having better beta-cell function at baseline. Remission is independent of BMI, underscoring the personal fat threshold concept that type 2 diabetes develops when an individual acquires more fat than can be individually tolerated even at a BMI which in the nonobese range. Observations on people of South Asian or Afro-American ethnicity confirm that substantial weight loss achieves remission in the same way as in the largely White Europeans studied in detail. Diagnosis of type 2 diabetes can now be regarded as an urgent signal that weight loss must be achieved to avoid a progressive decline of health.

The Low-Carbohydrate Diet: Short-Term Metabolic Efficacy Versus Longer-Term Limitations

Background: Diets have been a central component of lifestyle modification for decades. The Low-Carbohydrate Diet (LCD), originally conceived as a treatment strategy for intractable epilepsy (due to its association with ketogenesis), became popular in the 1970s and since then has risen to prominence as a weight loss strategy. Objective: To explore the efficacy, limitations and potential safety concerns of the LCD. Data Sources: We performed a narrative review, based on relevant articles written in English from a Pubmed search, using the terms ‘low carbohydrate diet and metabolic health’. Results: Evidence supports the efficacy of the LCD in the short-term (up to 6-months) for reduction in fat mass and remission of Type 2 Diabetes Mellitus (T2D). However, the longer-term efficacy of the LCD is disappointing, with diminishment of weight loss potential and metabolic benefits of the LCD beyond 6-months of its adoption. Furthermore, practical limitations of the LCD include the associated restriction of food choices that restrict the acceptability of the LCD for the individual, particularly over the longer term. There are also safety concerns of the LCD that stem from nutritional imbalances (with a relative excess of dietary fat and protein intake with associated dyslipidaemia and increased risk of insulin resistance and T2D development) and ketotic effects. Finally, the LCD often results in a reduction in dietary fibre intake, with potentially serious adverse consequences for overall health and the gut microbiota. Conclusions: Although widely adopted, the LCD usually has short-lived metabolic benefits, with limited efficacy and practicality over the longer term. Dietary modification needs tailoring to the individual, with careful a priori assessments of food preferences to ensure acceptability and adherence over the longer term, with avoidance of dietary imbalances and optimization of dietary fibre intake (primarily from plant-based fruit and vegetables), and with a posteriori assessments of the highly individual responses to the LCD. Finally, we need to change our view of diets from simply an excipient for weight loss to an essential component of a healthy lifestyle.

Impact of dietary counseling on the perception of diet in patients with gestational diabetes mellitus

AIMS/INTRODUCTION

Medical nutrition therapy is the cornerstone of gestational diabetes mellitus (GDM) treatment. Patients with GDM should receive dietary counseling regarding diet and exercise.

MATERIALS AND METHODS

To study patients' perception level of diet and their level of understanding after dietary counseling, we analyzed 225 reports of dietary counseling of patients with GDM prepared by dieticians. We also assessed the patients' level of understanding after dietary counseling by asking questions regarding the counseling content. The answers to the questions were aggregated, and substantially similar answers were grouped and categorized.

RESULTS

The dieticians' suggestions were well understood by the patients. Moreover, the patients also identified their previous incorrect eating habits, such as excessive carbohydrate restriction or inappropriate fruit intake. Although distributed frequent meals were recommended by the dieticians, few patients actually practiced this for various reasons. Some patients were apparently influenced by dietary information from the mass media.

CONCLUSION

Dietary counseling was regarded as helpful and acceptable to most patients with GDM in our hospital, and many suggestions were recognized as informative for modification of previous dietary habits. By providing the results of the questionnaire survey to the dieticians, they can improve the quality of their counseling, which is expected to result in better individual care of the patients.

Dietary Management of Type 2 Diabetes in the MENA Region: A Review of the Evidence

The alarmingly rising trend of type 2 diabetes constitutes a major global public health challenge particularly in the Middle Eastern and North African (MENA) region where the prevalence is among the highest in the world with a projection to increase by 96% by 2045. The economic boom in the MENA region over the past decades has brought exceptionally rapid shifts in eating habits characterized by divergence from the traditional Mediterranean diet towards a more westernized unhealthy dietary pattern, thought to be leading to the dramatic rises in obesity and non-communicable diseases. Research efforts have brought a greater understanding of the different pathways through which diet and obesity may affect diabetes clinical outcomes, emphasizing the crucial role of dietary interventions and weight loss in the prevention and management of diabetes. The purpose of this review is to explore the mechanistic pathways linking obesity with diabetes and to summarize the most recent evidence on the association of the intake of different macronutrients and food groups with the risk of type 2 diabetes. We also summarize the most recent evidence on the effectiveness of different macronutrient manipulations in the prevention and management of diabetes while highlighting the possible underlying mechanisms of action and latest evidence-based recommendations. We finally discuss the need to adequately integrate dietetic services in diabetes care specific to the MENA region and conclude with recommendations to improve dietetic care for diabetes in the region.

Circulating inflammatory markers may mediate the relationship between low carbohydrate diet and circadian rhythm in overweight and obese women

Background

Low carbohydrate diet (LCD) can improve inflammation and obesity and also circadian rhythm disorders can lead to increased inflammation in obese individuals. The purpose of this study is to evaluate the association between adherence of LCD and circadian rhythm mediated by inflammatory markers including transforming growth factor-β (TGF-β), interleukin-1β (IL-1β) and Galectin-3 in overweight and obese women.

Methods

304 women affected by overweight and obesity were enrolled. We evaluated LCD scores by Semi-quantitative food frequency questionnaire (FFQ) of 147 items. The morning-evening questionnaire (MEQ) was applied to evaluate the circadian rhythm. Biochemical parameters such as inflammatory markers and anthropometric components were assessed.

Results

There was a negative significant correlation between adherence of LCD and circadian rhythm status. In other words, as the LCD scores increased, the odds of circadian rhythm disturbance in intermediate group and morning type persons decreased compared to evening type. It was showed that, IL-1β and Galectin-3 in intermediate and morning type groups, destroyed the significance of this relationship and may be considered as mediating markers.

Conclusion

Adherence of LCD can improve the circadian rhythm by reducing levels of inflammatory markers and may be considered as a treatment for obesity.

Current Evidence Regarding Low-carb Diets for The Metabolic Control of Type-2 Diabetes

The management of diabetes requires a medical nutrition therapy as an essential part of this treatment. There should be no "one-size-fits-all" eating pattern for different patient´s profiles with diabetes. It is clinically complex to suggest an ideal percentage of calories from carbohydrates, protein and lipids recommended for all patients with diabetes. Among the eating patterns that have shown beneficial effects on metabolic control of patients with type 2 diabetes is the lowcarb diet, since the carbohydrate ingestion is viewed as the most important determinant of postprandial glucose and insulin response. In this context, theoretically, it could make sense to reduce the daily amount of carbohydrates ingested, to achieve lower levels of HbA1c. There could be risks associated to this approach. The adherence to a low-carb diet is here also discussed. This narrative review shows on the current evidence for answering these questions regarding low-carb diet as a possible alternative eating pattern for type 2 diabetes.

Effect of a 90 g/day low-carbohydrate diet on glycaemic control, small, dense low-density lipoprotein and carotid intima-media thickness in type 2 diabetic patients: An 18-month randomised controlled trial

Aim

This study explored the effect of a moderate (90 g/d) low-carbohydrate diet (LCD) in type 2 diabetes patients over 18 months.

Methods

Ninety-two poorly controlled type 2 diabetes patients aged 20–80 years with HbA1c ≥7.5% (58 mmol/mol) in the previous three months were randomly assigned to a 90 g/d LCD r traditional diabetic diet (TDD). The primary outcomes were glycaemic control status and change in medication effect score (MES). The secondary outcomes were lipid profiles, small, dense low-density lipoprotein (sdLDL), serum creatinine, microalbuminuria and carotid intima-media thickness (IMT).

Results

A total of 85 (92.4%) patients completed 18 months of the trial. At the end of the study, the LCD and TDD group consumed 88.0±29.9 g and 151.1±29.8 g of carbohydrates, respectively (p < 0.05). The 18-month mean change from baseline was statistically significant for the HbA1c (-1.6±0.3 vs. -1.0±0.3%), 2-h glucose (-94.4±20.8 vs. -18.7±25.7 mg/dl), MES (-0.42±0.32 vs. -0.05±0.24), weight (-2.8±1.8 vs. -0.7±0.7 kg), waist circumference (-5.7±2.7 vs. -1.9±1.4 cm), hip circumference (-6.1±1.8 vs. -2.9±1.7 cm) and blood pressure (-8.3±4.6/-5.0±3 vs. 1.6±0.5/2.5±1.6 mmHg) between the LCD and TDD groups (p<0.05). The 18-month mean change from baseline was not significantly different in lipid profiles, sdLDL, serum creatinine, microalbuminuria, alanine aminotransferase (ALT) and carotid IMT between the groups.

Conclusions

A moderate (90 g/d) LCD showed better glycaemic control with decreasing MES, lowering blood pressure, decreasing weight, waist and hip circumference without adverse effects on lipid profiles, sdLDL, serum creatinine, microalbuminuria, ALT and carotid IMT than TDD for type 2 diabetic patients.

Diet and exercise in the prevention and treatment of type 2 diabetes mellitus

Evidence from observational studies and randomized trials suggests that prediabetes and type 2 diabetes mellitus (T2DM) can develop in genetically susceptible individuals in parallel with weight (that is, fat) gain. Accordingly, studies show that weight loss can produce remission of T2DM in a dose-dependent manner. A weight loss of ~15 kg, achieved by calorie restriction as part of an intensive management programme, can lead to remission of T2DM in ~80% of patients with obesity and T2DM. However, long-term weight loss maintenance is challenging. Obesity and T2DM are associated with diminished glucose uptake in the brain that impairs the satiating effect of dietary carbohydrate; therefore, carbohydrate restriction might help maintain weight loss and maximize metabolic benefits. Likewise, increases in physical activity and fitness are an important contributor to T2DM remission when combined with calorie restriction and weight loss. Preliminary studies suggest that a precision dietary management approach that uses pretreatment glycaemic status to stratify patients can help optimize dietary recommendations with respect to carbohydrate, fat and dietary fibre. This approach might lead to improved weight loss maintenance and glycaemic control. Future research should focus on better understanding the individual response to dietary treatment and translating these findings into clinical practice.

Effect of a Moderate Carbohydrate-Restricted Diet on DPP-4 Inhibitor Action among Individuals with Type 2 Diabetes Mellitus: A 6-Month Intervention Study

To decrease body weight and insulin resistance, a calorie-restricted diet-with minimal caloric intake required for daily activities-is the primary treatment strategy for patients with type 2 diabetes (T2D) in Japan. However, many patients cannot continue with this diet for long, because calorie restriction is difficult and nutritional balance is hard to understand. Carbohydrate-restricted diets are easier for patients than conventional calorie-restricted diet. In this study we aimed to elucidate the effects of a moderate carbohydrate-restricted diet on glucose metabolism and renal function in patients with T2D on dipeptidyl peptidase-4 (DPP-4) inhibitors. Nineteen outpatients with T2D continued on a moderate carbohydrate-restricted diet (targeting 50% of calories) for 6 mo. Meanwhile, 10 other outpatients with T2D on DPP-4 inhibitors had the conventional calorie-restricted diet using the food exchange table. No change in prescription drugs occurred for both groups during the study period. After the intervention, the carbohydrate content in dietary intake was lowered significantly from 56.8±8.3 to 46.8±10.1%, while the lipid concentration, primarily n-6 polyunsaturated fatty acids, was significantly increased. There was no significant change in protein intake. Hemoglobin A1c (HbA1c) fell from 7.22±0.74% to 6.95±0.72% (mean±SD). Furthermore, salt intake decreased significantly from 6.8±2.5 g prior to the intervention, to 5.7±1.9 g after the intervention. The estimated glomerular filtration rates (eGFR) decreased slightly, while serum creatinine levels did not change. These findings suggest that a moderate carbohydrate-restricted diet (50%) is effective in patients with T2D, without affecting kidney function.

5. Facilitating Behavior Change and Well-being to Improve Health Outcomes: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc20-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Two Stories about Diet and Diabetes in Europe

Unhealthy weight gain and diabetes are global challenges that threaten not only the well-beings of hundreds of millions of persons but also the global economy. The authors in this article describe two overlapping stories, one is about a 150-year-old diet, known as the Banting Diet, which is similar to the Atkins or Keto Diet, and the other is about a provider-patient relationship story that helped the patient make lifestyle modifications that were effective in significant weight loss, improved quality of life, and reduced need for exogenous insulin for Type 2 diabetes. Both of the stories are from England but might be useful worldwide.

Optimal Dietary Strategies for Prevention of Atherosclerotic Cardiovascular Disease in Diabetes: Evidence and Recommendations

PURPOSE OF REVIEW

This review presents the current available evidence of the effects of several dietary patterns on atherosclerotic cardiovascular disease (ASCVD) risk in patients with type 2 diabetes (T2D).

RECENT FINDINGS

Evidence demonstrates improvements in cardiovascular risk factors with some dietary patterns in the general population. However, evidence is limited for glycemic control and cardiovascular benefit in patients with T2D for Dietary Approaches to Stop Hypertension and plant-based dietary patterns. Evidence suggests that carbohydrate-restricted dietary patterns improve glycemic control and decrease the use of anti-hyperglycemic medications. The Mediterranean dietary pattern has the most evidence for glycemic control and decreased ASCVD risk in patients with T2D. There is no evidence on ASCVD outcomes in patients with T2D for any other dietary pattern. The Mediterranean dietary pattern has the most evidence for cardiovascular benefit in patients with T2D. Future research should examine the effect of dietary patterns on ASCVD outcomes.

Review of current evidence and clinical recommendations on the effects of low-carbohydrate and very-low-carbohydrate (including ketogenic) diets for the management of body weight and other cardiometabolic risk factors: A scientific statement from the National Lipid Association Nutrition and Lifestyle Task Force

Historically, low-carbohydrate (CHO) and very-low-CHO diets have been used for weight loss. Recently, these diets have been promoted for type 2 diabetes (T2D) management. This scientific statement provides a comprehensive review of the current evidence base available from recent systematic reviews and meta-analyses on the effects of low-CHO and very-low-CHO diets on body weight, lipoprotein lipids, glycemic control, and other cardiometabolic risk factors. In addition, evidence on emerging risk factors and potential safety concerns of low-CHO and very-low-CHO diets, especially for high-risk individuals, such as those with genetic lipid disorders, was reviewed. Based on the evidence reviewed, low-CHO and very-low-CHO diets are not superior to other dietary approaches for weight loss. These diets may have advantages related to appetite control, triglyceride reduction, and reduction in the use of medication in T2D management. The evidence reviewed showed mixed effects on low-density lipoprotein cholesterol levels with some studies showing an increase. There was no clear evidence for advantages regarding effects on other cardiometabolic risk markers. Minimal data are available regarding long-term (>2 years) efficacy and safety. Clinicians are encouraged to consider the evidence discussed in this scientific statement when counseling patients on the use of low-CHO and very-low-CHO diets.

Evidenced-Based Nutrition for Gestational Diabetes Mellitus

PURPOSE OF REVIEW

To review the latest evidence for dietary interventions for treatment of gestational diabetes (GDM).

RECENT FINDINGS

High-quality systematic reviews demonstrate no major advantages between the low-carbohydrate or calorie-restricted diets. However, the low glycemic index (GI) diet, characterized by intake of high-quality, complex carbohydrates, demonstrated lower insulin use and reduced risk of macrosomia in multiple reviews. Recent evidence suggests the Mediterranean diet is safe in pregnancy, though trials are needed to determine its efficacy over conventional dietary advice. Currently, there are insufficient data to support the safety of the ketogenic diet for the treatment of GDM. The low GI diet may improve maternal and neonatal outcomes in GDM. The liberalized carbohydrate intake is less restrictive, culturally adaptable, and may improve long-term maternal adherence. Further research is needed to establish the optimal, most sustainable, and most acceptable medical nutrition therapy for management of women with GDM.

Improving the scientific rigour of nutritional recommendations for adults with type 2 diabetes: A comprehensive review of the American Diabetes Association guideline-recommended eating patterns

AIMS

The global rate of type 2 diabetes (T2D) continues to rise. Guidelines that influence the worldwide treatment of this disease are central to changing this trajectory. We sought in this review to evaluate the appropriateness of sources cited in the American Diabetes Association's (ADA) guidelines on eating patterns for T2D management, identify additional relevant sources, and evaluate the evidence.

MATERIALS AND METHODS

We reviewed the evidence behind the ADA's recommendations on eating patterns in the 2018 and 2019 ADA Standards of Care and the 2014 ADA Nutrition Therapy Recommendations for Adults with Diabetes. Additionally, we conducted a comprehensive search to identify any additional studies not included in the cited evidence. To determine appropriateness of inclusion in the guidelines, the following criteria were applied: 1) it was a clinical trial or systematic review/meta-analysis of clinical trials; 2) it involved persons with T2D; 3) one of the study arms followed one of the eating patterns currently recommended; 4) its reported outcomes included glycaemic control; 5) outcomes were reported separately for persons with T2D.

RESULTS

We found a wide variation in the evidence for each eating pattern. Issues that have hampered the guideline process include: lack of a rigorous literature review, resulting in the omission of pertinent studies; an overreliance on prospective cohort studies; inconsistent standards for evidence; inclusion of studies not on persons with T2D; and bias.

CONCLUSIONS

The ADA Guidelines recommended eating patterns fall short of rigorous standards of scientific review according to state-of-the-art systematic review and guideline creation practices.

The effect of a low-carbohydrate high-fat diet and ethnicity on daily glucose profile in type 2 diabetes determined by continuous glucose monitoring

BACKGROUND AND AIMS

Nutrition is an integral part of type 2 diabetes (T2DM) treatment, but the optimal macronutrient composition is still debated and previous studies have not addressed the role of ethnicity in dietary response. The current study aims were to compare the effect of short-term glycemic response to low-carbohydrate high-fat (LC-HF) diet vs. high-carbohydrate low-fat (HC-LF) diet using continuous glucose monitoring (CGM) and to evaluate the response of individuals with T2DM of Yemenite (Y-DM) and non-Yemenite origin (NY-DM).

METHODS

Twenty T2DM males, ten Y-DM and ten NY-DM underwent meal tolerance test and indexes of insulin resistance and secretion were calculated. Subsequently, patients were connected to CGM to assess daily glycemic control and glucose variability in response to isocaloric HC-LF or LC-HF diet, receiving each diet for 2 days by providing prepared meals. Daily glucose levels, area under the glucose curve (G-AUC) and parameters of glucose variability [standard deviation (SD), mean amplitude of glycemic excursions (MAGE) and mean absolute glucose (MAG)] were evaluated.

RESULTS

The LC-HF resulted in a significantly lower G-AUC (p < 0.001) and in lower variability parameters (p < 0.001) vs. the HC-LF diet. However, Y-DM showed less reduction in glucose variability indices upon diet-switching vs. NY-DM; MAGE decreased, respectively, by 69% vs. 89%, p = 0.043 and MAG by 34% vs. 45%, p = 0.007 in Y-DM compared to NY-DM.

CONCLUSIONS

These results suggest that LC-HF diet is effective in reducing glycemic fluctuation in T2DM and that ethnicity may have a role in the response to dietary regime.

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.

Are excess carbohydrates the main link to diabetes & its complications in Asians?

Dietary carbohydrates form the major source of energy in Asian diets. The carbohydrate quantity and quality play a vital function in the prevention and management of diabetes. High glycaemic index foods elicit higher glycaemic and insulinaemic responses and promote insulin resistance and type 2 diabetes (T2D) through beta-cell exhaustion. This article reviews the evidence associating dietary carbohydrates to the prevalence and incidence of T2D and metabolic syndrome (MS) in control of diabetes and their role in the complications of diabetes. Cross-sectional and longitudinal studies show that higher carbohydrate diets are linked to higher prevalence and incidence of T2D. However, the association seems to be stronger in Asian-Indians consuming diets high in carbohydrates and more marked on a background of obesity. There is also evidence for high carbohydrate diets and risk for MS and cardiovascular disease (CVD). However, the quality of carbohydrates is also equally important. Complex carbohydrates such as brown rice, whole wheat bread, legumes, pulses and green leafy vegetables are good carbs. Conversely, highly polished rice or refined wheat, sugar, glucose, highly processed foods such as cookies and pastries, fruit juice and sweetened beverages and fried potatoes or French fries are obviously ‘bad’ carbs. Ultimately, it is all a matter of balance and moderation in diet. For Indians who currently consume about 65-75 per cent of calories from carbohydrates, reducing this to 50-55 per cent and adding enough protein (20-25%) especially from vegetable sources and the rest from fat (20-30%) by including monounsaturated fats (e.g. groundnut or mustard oil, nuts and seeds) along with a plenty of green leafy vegetables, would be the best diet prescription for the prevention and management of non-communicable diseases such as T2D and CVD.

Carbohydrate-Rich Diet Is Associated with Increased Risk of Incident Chronic Kidney Disease in Non-Diabetic Subjects

Despite the potential relationship with metabolic derangements, the association between dietary carbohydrate intake and renal function remains unknown. The present study investigated the impact of dietary carbohydrate intake on the development of incident chronic kidney disease (CKD) in a large-scale prospective cohort with normal renal function. A total of 6746 and 1058 subjects without and with diabetes mellitus (DM) were analyzed, respectively. Carbohydrate intake was assessed by a 24-h dietary recall food frequency questionnaire. The primary endpoint was CKD development, defined as a composite of estimated glomerular filtration rate (eGFR) of ≤60 mL/min/1.73 m2 and the development of proteinuria. CKD newly developed in 20.1% and 36.0% of subjects during median follow-ups of 140 and 119 months in the non-DM and DM subjects, respectively. Categorization of non-DM subjects into dietary carbohydrate density quartiles revealed a significantly higher risk of CKD development in the third and fourth quartiles than in the first quartile (P = 0.037 for first vs. third; P = 0.001 for first vs. fourth). A significant risk elevation was also found with increased carbohydrate density when carbohydrate density was treated as a continuous variable (P = 0.008). However, there was no significant difference in the incident CKD risk among those with DM according to dietary carbohydrate density quartiles. Carbohydrate-rich diets may increase the risk of CKD development in non-DM subjects.

[Nutrition for diabetic patients (Update 2019)]

Evidence demonstrates that medical diabetes treatment has to be accompanied by lifestyle modifications. Structured nutrition interventions and increased physical activity will help patients to normalise, respectively maintain their body weight.The main target of a medical nutrition therapy aims at achieving normal or nearly normal blood glucose levels, prevention of delay of diabetes associated complications.

Effect of an alcohol-free beer enriched with isomaltulose and a resistant dextrin on insulin resistance in diabetic patients with overweight or obesity

BACKGROUND & AIMS

The quality of carbohydrates has an essential role in nutritional management of type 2 diabetes mellitus (T2DM) because of its substantial impact on glucose homeostasis. Alcohol-free beer has beneficial bioactive components but it has a relatively high glycemic-index so its consumption is restricted in diabetic subjects. We aimed to explore the effect of an alcohol-free beer with modified carbohydrate composition almost completely eliminating maltose and adding isomaltulose (16.5 g/day) and a resistant maltodextrin (5.28 g/day) in comparison to a regular alcohol-free beer on glycemic control of diabetic subjects with overweight or obesity.

DESIGN

We randomized 41 subjects into two groups: a) consumption of 66 cL/day of; regular alcohol-free beer for the first 10 weeks and 66 cL/day of alcohol-free beer with modified carbohydrate composition for the next 10 weeks; b) the same described intervention in opposite order. There was a washout period for 6-8 weeks between the two interventions. Participants were counseled to adhere to a healthy diet for cardiovascular health and to increase physical activity. Clinical, biochemical, anthropometric, lifestyle and satiety assessments were performed at the beginning and at the end of each period.

RESULTS

Subjects showed significantly weight loss after the two ten weeks periods (-1.69 ± 3.21% and -1.77 ± 3.70% after experimental and regular alcohol-free beers, respectively, P = 0.881). Glucose and glycated hemoglobin did not significantly change after any period. Insulin concentrations and HOMA-IR significantly decreased (-11.1 [-21.3-4.64]% and -1.92 ± 32.8% respectively) after the intake of experimental alcohol-free beer but not after regular alcohol-free beer. Reductions remained statistically significant after adjusting for weight loss, energy intake, physical activity and intervention order. Subjects reported higher satiety scores after consuming experimental alcohol-free beer.

CONCLUSIONS

An alcohol-free beer including the substitution of regular carbohydrates for low doses of isomaltulose and the addition of a resistant maltodextrin within meals led to an improvement in insulin resistance in subjects with T2DM and overweight or obesity.

CLINICAL TRIAL REGISTRATION

The clinical trial has been registered in ClinicalTrials.gov (Identifier: NCT03337828).

The ups and downs of low-carbohydrate diets in the management of Type 1 diabetes: a review of clinical outcomes

Dietary management has been a mainstay of care in Type 1 diabetes since before the discovery of insulin when severe carbohydrate restriction was advocated. The use of insulin facilitated re-introduction of carbohydrate into the diet. Current management guidelines focus on a healthy and varied diet with consideration of glycaemic load, protein and fat. As a result of frustration with glycaemic outcomes, low-carbohydrate diets have seen a resurgence in popularity. To date, low-carbohydrate diets have not been well studied in the management of Type 1 diabetes. Studies looking at glycaemic outcomes from low-carbohydrate diets have largely been cross-sectional, without validated dietary data and with a lack of control groups. The participants have been highly motivated self-selected individuals who follow intensive insulin management practices, including frequent blood glucose monitoring and additional insulin corrections with tight glycaemic targets. These confounders limit the ability to determine the extent of the impact of dietary carbohydrate restriction on glycaemic outcomes. Carbohydrate-containing foods including grains, fruit and milk are important sources of nutrients. Hence, low-carbohydrate diets require attention to vitamin and energy intake to avoid micronutrient deficiencies and growth issues. Adherence to restricted diets is challenging and can have an impact on social normalcy. In individuals with Type 1 diabetes, adverse health risks such as diabetic ketoacidosis, hypoglycaemia, dyslipidaemia and glycogen depletion remain clinical concerns. In the present paper, we review studies published to date and provide clinical recommendations for ongoing monitoring and support for individuals who choose to adopt a low-carbohydrate diet. Strategies to optimize postprandial glycaemia without carbohydrate restriction are presented.

James Lind Alliance research priorities: what role do carbohydrates, fats and proteins have in the management of Type 2 diabetes, and are there risks and benefits associated with particular approaches?

AIMS

To assess the role played by carbohydrates, fat and proteins in the management of Type 2 diabetes.

BACKGROUND

Diabetes research tends to reflect the interests of academics or the pharmaceutical industry, rather than those of people living with Type 2 diabetes. The James Lind Alliance and Diabetes UK addressed this issue by defining the research priorities of people living with Type 2 diabetes. Three of the top 10 research priority questions focused on lifestyle.

METHODS

A narrative review was undertaken with a structured search strategy using three databases. Search terms included the three macronutrients and Type 2 diabetes. No restrictions were placed on macronutrient quantity or length of study follow-up. Outcomes included changes in HbA_1c , body weight, insulin sensitivity and cardiovascular risk.

RESULTS

There is no strong evidence that there is an optimal ratio of macronutrients for improving glycaemic control or reducing cardiovascular risk. Challenges included defining the independent effect of macronutrient manipulation and identifying the effects of macronutrients, independent of foods and dietary patterns. Extreme intakes of macronutrients may be associated with health risks.

CONCLUSIONS

It is challenging to formulate food-based guidelines from studies based on macronutrient manipulation. Structured education should be offered to support individuals in discovering their optimal, individual dietary approach. Recommendations for dietary guidelines should be expressed in terms of foods and not macronutrients.

Carbohydrate restriction for glycaemic control in Type 2 diabetes: a systematic review and meta-analysis

AIM

To conduct a systematic review and meta-analysis to evaluate the effect of carbohydrate restriction on glycaemic control in Type 2 diabetes.

METHODS

We searched Medline, EMBASE and CINAHL for the period between 1976 and April 2018. We included randomized controlled trials comparing carbohydrate restriction with a control diet which aimed to maintain or increase carbohydrate intake, and that reported HbA_1c as an outcome and reported the amount of carbohydrate consumed during or at the end of the study, with outcomes reported at ≥3 months.

RESULTS

We identified 1402 randomized controlled trials, 25 of which met the inclusion criteria, incorporating 2132 participants for the main outcome. Definitions of low carbohydrate varied among the studies. The pooled effect estimate from meta-analysis was a weighted mean difference of -0.09% [95% CI -0.27, 0.08 (P = 0.30); I² 72% (P <0.001)], suggesting no effect on HbA_1c of restricting the quantity of carbohydrate. A subgroup analysis of diets containing 50-130 g carbohydrate resulted in a pooled effect estimate of -0.49% [95% CI -0.75, -0.23 (P <0.001); I² 0% (P = 0.56)], suggesting a clinically and statistically significant effect on HbA_1c in favour of low-carbohydrate diets in studies of ≤6 months' duration.

CONCLUSIONS

There was no overall pooled effect on HbA_1c in favour of restricting carbohydrate; however, restriction of carbohydrate to 50-130 g per day had beneficial effects on HbA_1c in trials up to 6 months. Future randomized controlled trials should be of >12 months' duration, assess pre-study carbohydrate intake, use recognized definitions of low-carbohydrate diets and examine reasons for non-adherence to prescribed diets in greater detail.

Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: A randomised clinical trial

BACKGROUND

Low-carbohydrate, high-fat (LCHF) diets are useful for treating a range of health conditions, but there is little research evaluating the degree of carbohydrate restriction on outcome measures. This study compares anthropometric and cardiometabolic outcomes between differing carbohydrate-restricted diets.

OBJECTIVE

Our hypothesis was that moderate carbohydrate restriction is easier to maintain and more effective for improving cardiometabolic health markers than greater restriction.

DESIGN

A total of 77 healthy participants were randomised to a very low-carbohydrate ketogenic diet (VLCKD), low-carbohydrate diet (LCD), or moderate-low carbohydrate diet (MCD), containing 5%, 15% and 25% total energy from carbohydrate, respectively, for 12-weeks. Anthropometric and metabolic health measures were taken at baseline and at 12 weeks. Using ANOVA, both within and between-group outcomes were analysed.

RESULTS

Of 77 participants, 39 (51%) completed the study. In these completers overall, significant reductions in weight and body mass index occurred ((mean change) 3.7 kg/m2; 95% confidence limits (CL): 3.8, 1.8), along with increases in high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, (0.49 mmol/L; 95% CL; 0.06, 0.92; p = 0.03), and total cholesterol concentrations (0.11 mmol/L; 95% CL; 0.00, 0.23; p = 0.05). Triglyceride (TG) levels were reduced by 0.12 mmol/L (95% CL; -0.20, 0.02; p = 0.02). No significant changes occurred between groups. The largest improvements in high density lipoprotein cholesterol (HDL-c) and TG and anthropometric changes occurred for the VLCKD group.

CONCLUSIONS

Low-carbohydrate, high-fat diets have a positive effect on markers of health. Adherence to the allocation of carbohydrate was more easily achieved in MCD, and LCD groups compared to VLCKD and there were comparable improvements in weight loss and waist circumference and greater improvements in HDL-c and TG with greater carbohydrate restriction.

Dietary Approaches to the Management Of type 2 Diabetes (DIAMOND): protocol for a randomised feasibility trial

INTRODUCTION

Some clinicians have observed that low-carbohydrate, low-energy diets can improve blood glucose control, with reports of remission from type 2 diabetes in some patients. In clinical trials, support for low-carbohydrate, low-energy diets has been provided by specialist staff and these programmes are unsuitable for widespread deployment in routine primary care. The aim of this trial is to test whether a newly developed behavioural support programme can effectively deliver a low-energy, low-carbohydrate diet in a primary care setting.

METHODS AND ANALYSIS

This is a feasibility randomised controlled trial (RCT) with embedded qualitative study. Thirty adult patients with type 2 diabetes and body mass index ≥30 kg/m² in 2-4 general practices will be randomised 2:1 intervention or control and followed up over 12 weeks. The intervention diet comprises 8 weeks of a low-carbohydrate food-based diet providing around 800 kcal/day, followed by 4 weeks of weight maintenance. This programme will be delivered by practice nurses, who will also support patients through goal-setting, motivation and self-monitoring across four appointments, and provide a self-help booklet with recipes, shopping lists and other behavioural support. Primary outcome measures of feasibility will be met if CIs do not cross the following proportions: that 60% of intervention group participants attempt the dietary intervention, healthcare professionals conduct the intervention delivery session with at least 60% of essential elements present and 60% of participants attend the final follow-up session. Secondary outcome measures will assess process and qualitative measures, as well as exploratory outcomes including change in haemoglobin A1c and change in weight.

ETHICS AND DISSEMINATION

This study has been granted ethical approval by the National Research Ethics Service, South Central Oxford B Research Ethics Committee (ref: 18/SC/0071). The study results will inform whether to progress to a full-scale RCT to test the efficacy of offering this programme for patients with type 2 diabetes in primary care.

TRIAL REGISTRATION NUMBER

ISRCTN62452621; Pre-results.

Carbohydrate quantity in the dietary management of type 2 diabetes: A systematic review and meta-analysis

AIMS

This systematic review and meta-analysis (registration number: CRD42013005825) compares the effects of low carbohydrate diets (LCDs) on body weight, glycaemic control, lipid profile and blood pressure with the effects of higher carbohydrate diets (HCDs) in adults with type 2 diabetes.

METHODS

MEDLINE, EMBASE, CENTRAL, CINAHL, Food Science Source and SweMed+ databases were systematically searched to identify randomized controlled trials (duration ≥3 months) investigating the effects of an LCD compared to an HCD in the management of type 2 diabetes. Data were extracted and pooled using a random effects model and were expressed as mean differences and risk ratio. Subgroup analyses were undertaken to examine the effects of duration of intervention, extent of carbohydrate restriction and risk of bias. The certainty of evidence was assessed using GRADE.

RESULTS

Of the 1589 studies identified, 23, including 2178 participants, met inclusion criteria. Reductions were slightly greater with LCDs than with HCDs for HbA1c (-1.0 mmol/mol; CI, -1.9, -0.1 [-0.09%; CI, -0.17, -0.01]) and for triglycerides (-0.13 mmol/L; CI, -0.24, -0.02). Changes in weight, HDL- and LDL-cholesterol, total cholesterol and blood pressure did not differ significantly between groups. Subgroup analyses suggested that the difference in HbA1c was evident only in studies with a duration of ≤6 months and with a high risk of bias.

CONCLUSIONS

The proportion of daily energy provided by carbohydrate intake is not an important determinant of response to dietary management, especially when considering longer term trials. A range of dietary patterns, including those traditional in Mediterranean countries, seems suitable for translating nutritional recommendations for individuals with diabetes into practical advice.

5. Lifestyle Management: Standards of Medical Care in Diabetes-2019

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Fat Versus Carbohydrate-Based Energy-Restricted Diets for Weight Loss in Patients With Type 2 Diabetes

PURPOSE OF REVIEW

The prevalence of combined obesity and diabetes has increased dramatically in the last few decades. Although medical and surgical weight management are variably effective in addressing this epidemic, it is essential to parallel these strategies with a hypocaloric diet comprising the appropriate macronutrient composition to induce weight loss, enhance glycemic control, and improve cardiovascular risk factors. This review reports the current evidence of the role of carbohydrates and fat-based diets for weight management in patients with combined type 2 diabetes (T2D) and obesity.

RECENT FINDINGS

Low-carbohydrate diets were shown to decrease postprandial glucose levels whereas high-carbohydrate, low-fat diets are considered cardio-protective. A diet with an optimal macronutrient composition remains uncertain for patients with combined T2D and obesity. Further research is still needed to define the best dietary composition that achieves the maximum benefits on weight management, glycemic control, and cardiovascular risk factors.