Mixed methods pilot study of a low-carbohydrate diabetes prevention programme among adults with pre-diabetes in the USA

A systematic review of the mechanisms influencing engagement in diabetes prevention programmes for people with pre-diabetes

AIMS

To identify barriers and enablers that influence engagement in and acceptability of diabetes prevention programmes for people with pre-diabetes. The results will provide insights for developing strategies and recommendations to improve design and delivery of diabetes prevention programmes with enhanced engagement and acceptability for people with pre-diabetes.

METHODS

This review used a critical realist approach to examine context and mechanisms of diabetes prevention programmes. Medline, Embase, PsycInfo, Cinahl, Web of Science, Scopus and Pre-Medline were searched for English language studies published between 2000 and 2023. A quality assessment was conducted using Joanna Briggs Institute critical appraisal tools.

RESULTS

A total of 90 papers met inclusion criteria. The included studies used a variety of quantitative and qualitative methodologies. Data extracted focused on barriers and enablers to engagement in and acceptability of diabetes prevention programmes, with seven key mechanisms identified. These included financial, environmental, personal, healthcare, social and cultural, demographic and programme mechanisms. Findings highlighted diverse factors that influenced engagement in preventive programmes and the importance of considering these factors when planning, developing and implementing future diabetes prevention programmes.

CONCLUSIONS

Mechanisms identified in this review can inform design and development of diabetes prevention programmes for people with pre-diabetes and provide guidance for healthcare professionals and policymakers. This will facilitate increased participation and engagement in preventive programmes, potentially reducing progression and/or incidence of pre-diabetes to type 2 diabetes and improving health outcomes.

A very low-carbohydrate diabetes prevention program for veterans with prediabetes: a single-arm mixed methods pilot study

Introduction

All Veterans Affairs (VA) Medical Centers offer the MOVE! Weight Management Program to help patients achieve and maintain a healthy weight through a calorie-restricted, low-fat diet and increased physical activity. Yet, most MOVE! participants do not achieve clinically significant weight loss of ≥5%. A carbohydrate-restricted diet may help more Veterans to achieve ≥5% weight loss.

Methods

This was a single-arm explanatory sequential mixed methods pilot study conducted in one VA health care system. Veterans with prediabetes and body mass index ≥25 kg/m2 were invited to participate in a group-based, virtual, very low-carbohydrate Diabetes Prevention Program (VLC-DPP) consisting of 23 sessions over 12 months. Participants were taught to follow a very low-carbohydrate eating pattern, defined as 20-35 grams of net carbohydrates per day. The primary outcomes were measures of feasibility and acceptability, including program uptake and session attendance. Secondary outcomes included change in weight, hemoglobin A1c, lipids, and patient-reported measures of food cravings, stress eating, perceived health status, and motivation. Interviews were conducted at 6 months to identify factors that facilitated or hindered participants' achievement of ≥5% weight loss.

Results

Among 108 screened Veterans, 21 enrolled in the study (19%), and 18 were included in the analytic cohort. On average, participants attended 12.4/16 weekly sessions and 3.6/8 bimonthly or monthly sessions. At 12 months, mean percent weight loss was 9.4% (SD = 10.7) with 9 participants (50%) achieving ≥5% weight loss. Three factors facilitated achievement of ≥5% weight loss among 10/16 interviewees: (1) enjoyment of low-carbohydrate foods; (2) careful monitoring of carbohydrate intake; and (3) reduced hunger and food cravings. Three factors hindered achievement of ≥5% weight loss among 6/16 interviewees: (1) food cravings, particularly for sweets; (2) challenges with maintaining a food log; and (3) difficulty with meal planning.

Conclusion

A VLC-DPP is feasible and acceptable and shows preliminary efficacy among Veterans with prediabetes. The program's weight loss effectiveness compared to standard MOVE! should be evaluated in a larger-scale trial. Such a program may be offered in addition to the standard MOVE! program to expand the menu of evidence-based lifestyle counseling options for Veterans.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT04881890, identifier NCT04881890.

Two decades of diabetes prevention efforts: A call to innovate and revitalize our approach to lifestyle change

The impact of global diabetes prevention efforts has been modest despite the promise of landmark diabetes prevention trials nearly twenty years ago. While national and regional initiatives show potential, challenges remain to adapt large-scale strategies in the real-world that fits individuals and their communities. Additionally, the sedentary lifestyle changes during the COVID-19 pandemic and guidelines that now call for earlier screening (e.g., US Preventative Task Force) will increase the pool of eligible adults worldwide. Thus, a more adaptable, person-centered approach that expands the current toolkit is urgently needed to innovate and revitalize our approach to diabetes prevention. This review identifies key priorities to optimize the population-level delivery of diabetes prevention based on a consensus-based evaluation of the current evidence among experts in global translational programs; key priorities identified include (1) participant eligibility, (2) intervention intensity, (3) delivery components, (4) behavioral economics, (5) technology, and (6) the role of pharmacotherapy. We offer a conceptual framework for a broader, person-centered approach to better address an individual's risk, readiness, barriers, and digital competency.

Testing a very low-carbohydrate adaption of the Diabetes Prevention Program among adults with prediabetes: study protocol for the Lifestyle Education about prediabetes (LEAP) trial

BACKGROUND

The Center for Disease Control and Prevention's National Diabetes Prevention Program (NDPP) aims to help individuals with prediabetes avoid progression to type 2 diabetes mellitus (T2DM) through weight loss. Specifically, the NDPP teaches individuals to follow a low-fat, calorie-restricted diet and to engage in regular physical activity to achieve ≥ 5% body weight loss. Most NDPP participants, however, do not achieve this weight loss goal, and glycemic control remains largely unchanged. One promising opportunity to augment the NDPP's weight loss and glycemic effectiveness may be to teach participants to follow a very low-carbohydrate diet (VLCD), which can directly reduce post-prandial glycemia and facilitate weight loss by reducing circulating insulin and enabling lipolysis. To date, there have been no high-quality, randomized controlled trials to test whether a VLCD can prevent progression to T2DM among individuals with prediabetes. The aim of this study is to test the effectiveness of a VLCD version the NDPP (VLC-NDPP) versus the standard NDPP. We hypothesize the VLC-NDPP will demonstrate greater improvements in weight loss and glycemic control.

METHODS

We propose to conduct a 12-month, 1:1, randomized controlled trial that will assign 300 adults with overweight or obesity and prediabetes to either the NDPP or VLC-NDPP. The primary outcome will be glycemic control as measured by change in hemoglobin A1c (HbA1c) from baseline to 12 months. Secondary outcomes will include percent body weight change and changes in glycemic variability, inflammatory markers, lipids, and interim HbA1c. We will evaluate progression to T2DM and initiation of anti-hyperglycemic agents. We will conduct qualitative interviews among a purposive sample of participants to explore barriers to and facilitators of dietary adherence. The principal quantitative analysis will be intent-to-treat using hierarchical linear mixed effects models to assess differences over time.

DISCUSSION

The NDPP is the dominant public health strategy for T2DM prevention. Changing the program's dietary advice to include a carbohydrate-restricted eating pattern as an alternative option may enhance the program's effectiveness. If the VLC-NDPP shows promise, this trial would be a precursor to a multi-site trial with incident T2DM as the primary outcome.

TRIAL REGISTRATION

NCT05235425. Registered February 11, 2022.

Facilitators and barriers for lifestyle change in people with prediabetes: a meta-synthesis of qualitative studies

BACKGROUND

The increasing prevalence of type 2 diabetes worldwide is a major global public health concern. Prediabetes is a reversible condition and is seen as the critical phase for the prevention of type 2 diabetes. The aim of this study is to identify and synthesize current evidence on the perceived barriers and facilitators of lifestyle change among people with prediabetes in terms of both initial change and lifestyle change maintenance.

METHODS

A systematic literature search in six bibliographic databases was conducted in April 2021. Potential studies were assessed for eligibility based on pre-set criteria. Quality appraisal was done on the included studies, and the thematic synthesis approach was applied to synthesize and analyse the data from the included studies.

RESULTS

Twenty primary studies were included, containing the experiences of 552 individuals. Thirteen studies reported participants perceived facilitators and barriers of lifestyle change when taking part in community-based lifestyle intervention programs, while seven studies reported on perceived facilitators and barriers of lifestyle change through consultations with health care professionals (no intervention involved). Three analytical themes illuminating perceived barriers and facilitators for lifestyle change were identified: 1) the individual's evaluation of the importance of initiating lifestyle change, 2) the second theme was strategies and coping mechanisms for maintaining lifestyle changes and 3) the last theme was the significance of supportive relations and environments in initiating and maintaining lifestyle change.

CONCLUSION

Awareness of prediabetes and the perception of its related risks affects the motivation for lifestyle change in people at risk of type 2 diabetes; but this does not necessarily lead to lifestyle changes. Facilitators and barriers of lifestyle change are found to be in a complex interplay within multiple ecological levels, including the interpersonal, intrapersonal, environmental and policy level. An integrated understanding and analysis of the perceived barriers and facilitators of lifestyle change might inform people with prediabetes, healthcare professionals, and policy makers in terms of the need for psychological, social, and environmental support for this population.

Prediabetes: Challenges, Novel Solutions, and Future Directions

Prediabetes: Prediabetes is a salient state of hyperglycaemia and/or hyperinsulinaemia that often precedes a diagnosis of Type 2 diabetes (T2D). It is projected that by 2040, almost 8% of the global population will have prediabetes, with approximately 70% progressing to T2D within their lifetime. Abnormal glucose tolerance increases the risk of associated complications, including cardiovascular disease, stroke, and microvascular diseases, all of which are major contributors to the global healthcare burden. T2D alone is predicted to cost the healthcare system upwards of 490 billion USD by 2030, thus addressing this growing burden is vital. Challenge One. Diagnosis and classification: Diagnosis poses a challenge and there is debate between leading world expert panels regarding thresholds, notably between the World Health Organization (WHO) and American Diabetes Association (ADA) for impaired fasting glucose. Hyperinsulinaemia may also go undetected as this is not currently routinely tested or used as diagnostic criteria. This has been largely due to cost and lack of consensus data for appropriate diagnostic threshold; however, with disease burden costs estimated to be close to half a billion USD by the end of the decade, an in-depth cost analysis for benefits-costs of early detection and treatment or prevention is warranted. Challenge Two. Health messaging and public perception: Prediabetes can revert to normoglycaemia with diet and lifestyle interventions. This, however, is not conveyed well in public health messaging. In addition to public perception about the likelihood of disease progression to T2D, prediabetes is not considered a disease state, which may also influence public perception regarding perceived urgency of treatment and necessity for intervention. Challenge Three. Intervention and treatment: Diet and lifestyle interventions are heralded as best practice when it comes to prediabetes management, and metformin for those at greatest risk of future T2D. Synergistic use of the available novel and promising interventions including low carbohydrate diets, higher protein diets, time restricted feeding, and high intensity interval training may help time-poor individuals achieve improvements in risk-factors including weight loss and glycaemic control (HbA1c and fasting plasma glucose). As large-scale feasibility and adherence are major obstacles to contend with in the rollout of diet and lifestyle interventions, personalised approaches, coupled with counselling based on social cognitive theory, may be increasingly utilised to target specific groups and individuals as programmes can be tailored to meet specific needs and preferences.

A Pragmatic Approach to Translating Low- and Very Low-Carbohydrate Diets Into Clinical Practice for Patients With Obesity and Type 2 Diabetes

Across all eating patterns, individuals demonstrate marked differences in treatment response; some individuals gain weight and others lose weight with the same approach. Policy makers and research institutions now call for the development and use of personalized nutrition counseling strategies rather than one-size-fits-all dietary recommendations. However, challenges persist in translating some evidence-based eating patterns into the clinical practice due to the persistent notion that certain dietary approaches-regardless of individuals' preferences and health outcomes-are less healthy than others. For example, low- and very low-carbohydrate ketogenic diets (VLCKDs)-commonly defined as 10-26% and <10% total daily energy from carbohydrate, respectively-are recognized as viable lifestyle change options to support weight loss, glycemic control, and reduced medication use. Yet, critics contend that such eating patterns are less healthy and encourage general avoidance rather than patient-centered use. As with all medical treatments, the potential benefits and risks must be considered in the context of patient-centered, outcome-driven care; this is the cornerstone of evidence-based medicine. Thus, the critical challenge is to identify and safely support patients who may prefer and benefit from dietary carbohydrate restriction. In this Perspective, we propose a pragmatic, 4-stepped, outcome-driven approach to help health professionals use carbohydrate-restricted diets as one potential tool for supporting individual patients' weight loss and metabolic health.

Ketogenic diets and appetite regulation

PURPOSE OF REVIEW

The popularity of ketogenic diets in the treatment of obesity has increased dramatically over the last years, namely due to their potential appetite suppressant effect. The purpose of this review was to examine the latest evidence regarding the impact of ketogenic diets on appetite.

RECENT FINDINGS

The majority of the studies published over the last 2 years adds to previous evidence and shows that ketogenic diets suppress the increase in the secretion of the hunger hormone ghrelin and in feelings of hunger, otherwise see when weight loss is induced by non-ketogenic diets. Research done using exogenous ketones point out in the same direction. Even though the exact mechanisms by which ketogenic diets suppress appetite remain to be fully determined, studies show that the more ketotic participants are (measured as β-hydroxybutyrate plasma concentration), the smaller is the increase in ghrelin and hunger and the larger is the increase in the release of satiety peptides. Further evidence for a direct effect of ketones on appetite comes from studies using exogenous ketones.

SUMMARY

The appetite suppressant effect of ketogenic diets may be an important asset for improving adherence to energy restricted diets and weight loss outcomes.

Effect of Sea Buckthorn on Plasma Glucose in Individuals with Impaired Glucose Regulation: A Two-Stage Randomized Crossover Intervention Study

Sea buckthorn (SB) has been indicated to have hypoglycemic potential, but its effects on glucose in people with impaired glucose regulation (IGR) are still unclear. This work presents a randomized, double-blinded, two-way crossover study. A total of 38 subjects with IGR completed the intervention of consuming sea buckthorn fruit puree (SBFP, 90 mL/day, five weeks), washing out (four weeks), and then consuming placebo (90 mL/day, five weeks) or in reverse order. In our methodology, a unified questionnaire was used to gather information on physical activity and dietary intakes, and physical examinations were performed to measure blood pressure, height, and weight. Fasting blood samples were collected to detect the fasting plasma glucose (FPG) and glycated serum protein (GSP). To calculate the area under the curve of 2 h postprandial plasma glucose (2 h PG-AUC), blood samples at t = 30, 60, and 120 min were also collected and analyzed. Effects of the intervention were evaluated by paired-sample Wilcoxon test and mixed model analyses. Our results show that the FPG in subjects with IGR decreased by a median reduction of 0.14 mmol/L after five weeks' consumption of SBFP, but increased by a median of 0.07 mmol/L after placebo intervention, and the comparison of these two interventions was statistically significant (p = 0.045). During the wash-out period, a similar difference was observed as the FPG decreased in the group that received SBFP intervention first, but increased in another group (p = 0.043). Both SBFP and placebo significantly raised GSP during the intervention period, but lowered it in the wash-out period (p < 0.05), while no significant difference was found between the two interventions. The 2 h PG-AUC remained relatively stable throughout the study. Our results indicated that consumption of SBFP for five weeks showed a slight downward trend on FPG in subjects with IGR.

Low-carbohydrate dietary pattern on glycemic outcomes trial (ADEPT) among individuals with elevated hemoglobin A1c: study protocol for a randomized controlled trial

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality globally. Strong evidence supports the importance of diet and other lifestyle factors in preventing T2DM. Among individuals with T2DM, low-carbohydrate diets lead to decreases in hemoglobin A1c (HbA1c). However, research on the effects of low-carbohydrate diets on glycemic outcomes among individuals not currently on glucose-lowering medications who have elevated HbA1c is limited.

METHODS

The objective of this randomized controlled trial is to study the effect of a healthy low-carbohydrate diet achieved through behavioral intervention and key food supplementation compared with usual diet on HbA1c and other metabolic risk factors among individuals with HbA1c from 6.0 to 6.9% who are not on glucose-lowering medications. In this parallel trial, 150 participants will be randomized to the intervention or control group for 6 months. The healthy low-carbohydrate diet target is < 40 g of net carbohydrates during the first 3 months and < 40 to 60 net grams for months 3 to 6. This diet is characterized by abundant unsaturated fat and protein, high-fiber foods such as non-starchy vegetables and nuts, and minimal refined carbohydrates. The primary outcome is the difference in HbA1c change from baseline to 6 months in the intervention compared with usual diet group. Secondary outcomes include differences between groups in 6-month changes in fasting glucose, systolic blood pressure, total-to-high-density lipoprotein (HDL) cholesterol ratio, and body weight. Exploratory outcomes include differences in 6-month changes in fasting insulin, homeostasis model assessment of insulin resistance, diastolic blood pressure, waist circumference, and 10-year cardiovascular disease risk. An intention-to-treat analysis will be used.

DISCUSSION

We expect that the results from this study will lead to new approaches for developing and implementing dietary approaches (other than the most commonly used reduced fat diet) that will substantially reduce risk of cardiometabolic disease among adults with or at high risk of T2DM. The study intervention involves behavioral counseling and promotes consumption of dietary components thought to reduce risk of cardiometabolic disease and has expected applicability in clinical practice.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03675360 . Registered on September 18, 2018 (prior to enrolment of the first participant).

Associations of low-carbohydrate and low-fat intakes with all-cause mortality in subjects with prediabetes with and without insulin resistance

BACKGROUND & AIMS

We investigated the associations of low-carbohydrate and low-fat diets with all-cause mortality in people with prediabetes according to insulin resistance status using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

We analyzed the NHANES participants with prediabetes from 2005 to 2008, and their vital status was linked to the National Death Index through the end of 2011. Low-carbohydrate and low-fat diets were defined as ≦40% and ≦30% of calories from carbohydrate and fat, respectively. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to determine insulin resistance. Weighted Cox proportional hazards regression models were used to compare the hazard ratios for the associations of low-carbohydrate and low-fat diets with all-cause mortality.

RESULTS

Among the 1687 participants with prediabetes, 96 of them had died after a median follow-up of 4.5 years. Participants with a HOMA-IR >3.0 had an increase in all-cause mortality compared with those who had a HOMA-IR ≦3.0 (HR 1.797, 95% CI 1.110 to 2.909, p = 0.019). Participants with ≦40% of calories from carbohydrate and >30% from fat (3.75 per 1000 person-years) had a lower all-cause mortality rate compared with those who had >40% from carbohydrate and >30% from fat (10.20 per 1000 person-years) or >40% from carbohydrate and ≦30% from fat (8.09 per 1000 person-years), with statistical significance observed in those who had a HOMA-IR ≦3.0.

CONCLUSIONS

A low-carbohydrate intake (≦40%) was associated with a lower all-cause mortality rate in people with prediabetes.

Continuous Glucose Monitoring With Low-Carbohydrate Diet Coaching in Adults With Prediabetes: Mixed Methods Pilot Study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is preventable; however, few patients with prediabetes participate in prevention programs. The use of user-friendly continuous glucose monitors (CGMs) with low-carbohydrate diet coaching is a novel strategy to prevent T2DM.

OBJECTIVE

This study aims to determine the patient satisfaction and feasibility of an intervention combining CGM use and low-carbohydrate diet coaching in patients with prediabetes to drive dietary behavior change.

METHODS

We conducted a mixed methods, single-arm pilot and feasibility study at a suburban family medicine clinic. A total of 15 adults with prediabetes with hemoglobin A_1c (HbA_1c) levels between 5.7% and 6.4% and a BMI >30 kg/m² were recruited to participate. The intervention and assessments took place during 3 in-person study visits and 2 qualitative phone interviews (3 weeks and 6 months after the intervention). During visit 1, participants were asked to wear a CGM and complete a food intake and craving log for 10 days. During visit 2, the food intake and craving log along with the CGM results of the participants were reviewed and the participants received low-carbohydrate diet coaching, including learning about carbohydrates and personalized feedback. A second CGM sensor, with the ability to scan and record glucose trends, was placed, and the participants logged their food intake and cravings as they attempted to reduce their total carbohydrate intake (<100 g/day). During visit 3, the participants reviewed their CGM and log data. The primary outcome was satisfaction with the use of CGM and low-carbohydrate diet. The secondary outcomes included feasibility, weight, and HbA_1c change, and percentage of time spent in hyperglycemia. Changes in attitudes and risk perception of developing diabetes were also assessed.

RESULTS

The overall satisfaction rate of our intervention was 93%. The intervention induced a weight reduction of 1.4 lb (P=.02) and a reduction of HbA_1c levels by 0.71% (P<.001) since enrollment. Although not significantly, the percentage of time above glucose goal and average daily glucose levels decreased slightly during the study period. Qualitative interview themes indicated no major barriers to CGM use; the acceptance of a low-carbohydrate diet; and that CGMs helped to visualize the impact of carbohydrates on the body, driving dietary changes.

CONCLUSIONS

The use of CGMs and low-carbohydrate diet coaching to drive dietary changes in patients with prediabetes is feasible and acceptable to patients. This novel method merits further exploration, as the preliminary data indicate that combining CGM use with low-carbohydrate diet coaching drives dietary changes, which may ultimately prevent T2DM.