Carbohydrate-last meal pattern lowers postprandial glucose and insulin excursions in type 2 diabetes

One minute of stair climbing and descending reduces postprandial insulin and glucose with 3-min improving insulin resistance following a mixed meal in young adults: A Randomized Controlled Crossover Trial

Background

Glycemic markers, including postprandial glucose, insulin, and insulin resistance, are strong predictors of morbidity and mortality in individuals with and without diabetes. Stair-climbing and -descending (SCD) at a comfortable pace for 3 minutes after a sugary beverage (300 kilocalories; 100% carbohydrate) lowers insulin, with insulin sensitivity improving in 10 minutes. If similar benefits are seen following consumption of a mixed meal is unknown. We hypothesize SCD will improve these markers in a dose-response manner following a mixed meal.

Methods

In a randomized, controlled, crossover trial, young adults (N = 31) performed SCD for 0 (seated control), 1, 3, and 10 minutes after a mixed meal (650 kilocalories; 53% carbohydrates, 33% fat, and 14% protein). Differences in glucose, insulin, and insulin sensitivity (ISI) from baseline to 30 min were analyzed using a mixed-effects ANOVA.

Results

A significant fixed-effect was found for change in glucose [F(2.551,67.17) = 4.724,p = 0.007)], insulin [F(2.692,74.49) = 11.28,p < 0.001)], and ISI [F(2.127,56.00) = 5.848,p = 0.004)]. Compared to the seated control (0 minutes), changes in glucose were lower after 1 minute (-14.0 (-7.2)mg/dL,p < 0.001), 3 minutes (-18.4 (-7.0)mg/dL,p = 0.0007), and 10 minutes (-10.0 (-8.1)mg/dL,p = 0.039); changes in insulin were lower after 1 minute (-1.8 (-0.9)μIU/mL,p = 0.0011), 3 minutes (-2.8 (-0.9)μIU/mL,p < 0.001), and 10 minutes (-1.1 (-0.9)μIU/mL,p = 0.033); and changes in ISI were significantly higher after 3 minutes (2.4 (1.5),p < 0.001) and 10 minutes (1.3 (1.6),p = 0.014) but not 1 minute (1.2 (1.5),p = 0.059).

Conclusion

Postprandial glucose and insulin improved with 1 minute, and insulin resistance improved with 3 minutes, of SCD at a self-selected, comfortable pace, after consumption of a mixed meal in apparently healthy young adults.

Protocol

Trial registration: ClinicalTrials.gov Identifier: NCT04232475.

The Impact of a Nutritional Intervention on Glycemic Control and Cardiovascular Risk Markers in Type 2 Diabetes

INTRODUCTION

Nutritional management plays a crucial role in treating patients with type 2 diabetes (T2D), working to prevent and control the progression of chronic non-communicable diseases.

OBJECTIVES

To evaluate the effects of individualized nutritional interventions on weight, body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting blood glucose (FBG), hemoglobin A1c (HbA1c), total cholesterol (TC), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), triglycerides (TGs), systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR)} over 12 months and subsequently at follow-up (15 months).

METHODS

This longitudinal experimental study (without randomization and blinding) enrolled 84 sedentary participants with T2D (both sexes, aged 18-80 years). They were divided into a control group of 40 participants who received only medical consultations, and an intervention group of 44 participants who received the same medical care along with a nutritional assessment. Consultations occurred quarterly from August 2020 to November 2022 (first-twelfth month), with six to nine patients per session. Subsequently, a follow-up was conducted from December 2022 to November 2023, during which the intervention group had only medical care (during the 12th-15th months). Personalized dietary planning was inspired by the Mediterranean/DASH diets adapted to Brazilian foods and socioeconomic cultures.

STATISTICAL ANALYSIS

Normal variables were compared between groups for each time point and also within each group across different time points using a two-way ANOVA (repeated measures for intragroup) followed by the Šídák post hoc test. Non-normal variables were compared between groups for each time point using Kruskal-Wallis followed by the Dunn post hoc test, and within each group across different time points using Friedman followed by the Dunn post hoc test. Data with a Gaussian distribution were presented as mean ± standard deviation (SD), and data with a non-Gaussian distribution were presented as median ± interquartile range (IQR). For all cases, α < 0.05 and p < 0.05 were adopted.

RESULTS

In the intervention group, significant reductions were observed between the first and twelfth month for all parameters (p < 0.05), (except for TC), along with an increase in HDL-C (p = 0.0105). Conversely, in the control group, there was a significant increase in HbA1c, weight, BMI, FBG, and WHR (p < 0.05) between the first and twelfth months. Regarding the comparison between groups, there was a significant difference for all analyzed parameters (p < 0.05) from the first to the twelfth month. In the follow-up, differences were also observed (p < 0.05), except for BMI (p > 0.05).

CONCLUSION

The individualized nutritional intervention improved eating habits, anthropometric, biochemical, and cardiovascular markers in T2D over 12 months, with sustained results during follow-up. The dietary plan inspired by the Mediterranean and DASH diets demonstrated good adaptation to the Brazilian food culture and the patients' socioeconomic contexts. Consistent monitoring and personalized nutritional management are essential for optimizing long-term outcomes. However, more clinical trials are necessary in order to optimize the level of evidence for longitudinal interventions.

Early time-restricted eating improves markers of cardiometabolic health but has no impact on intestinal nutrient absorption in healthy adults

Early time-restricted eating (eTRE) improves aspects of cardiometabolic health. Although the circadian system appears to regulate nutrient absorption, little is known about the effects of eTRE on intestinal absorption. In this randomized crossover trial, 16 healthy adults follow a controlled, weight maintenance diet for 9 days, consuming all calories between 0800 and 1400 (eTRE schedule) or 0800 and 2000 (control schedule). We measure the energy content of the diet, stool, and urine with bomb calorimetry and calculate intestinal energy absorption. The eTRE schedule is more effective than the control eating schedule for improving markers of cardiometabolic health, including 24-h mean glucose concentrations and glycemic variability, assessed as the mean amplitude of glycemic excursions. However, eTRE has no effect on intestinal energy and macronutrient absorption, gastrointestinal transit time, colonic hydrogen gas production, or stool microbial composition, suggesting eTRE does not impact gastrointestinal function. This trial is registered (ClinicalTrials.gov: NCT04877262).

Imprecision nutrition? Duplicate meals result in unreliable individual glycemic responses measured by continuous glucose monitors across four dietary patterns in adults without diabetes

Background

Continuous glucose monitors (CGMs) are being used to characterize postprandial glycemic responses and thereby provide personalized dietary advice to minimize glycemic excursions. However, the efficacy of such advice depends on reliable CGM responses.

Objective

To explore within-subject variability of CGM responses to duplicate meals in an inpatient setting.

Methods

CGM data were collected in two controlled feeding studies (NCT03407053 and NCT03878108) in 30 participants without diabetes capturing 1056 meal responses in duplicate ~1 week apart from four dietary patterns. One study used two different CGMs (Abbott Freestyle Libre Pro and Dexcom G4 Platinum) whereas the other study used only Dexcom. We calculated the incremental area under the curve (iAUC) for each 2-h post-meal period and compared within-subject iAUCs using the same CGM for the duplicate meals using linear correlations, intra-class correlation coefficients (ICC), Bland-Altman analyses, and compared individual variability of glycemic responses to duplicate meals versus different meals using standard deviations (SDs).

Results

There were weak to moderate positive linear correlations between within- subject iAUCs for duplicate meals (Abbott r=0.47, p<0.0001, Dexcom r=0.43, p<0.0001), with low within-participant reliability indicated by ICC (Abbott 0.31, Dexcom 0.14). Bland-Altman analyses indicated wide limits of agreement (Abbott -31.3 to 31.5 mg/dL, Dexcom -30.8 to 30.4 mg/dL) but no significant bias of mean iAUCs for duplicate meals (Abbott 0.1 mg/dL, Dexcom -0.2 mg/dL). Individual variability of glycemic responses to duplicate meals was similar to that of different meals evaluated each diet week for both Abbott (SDduplicate = 10.7 mg/dL , SDweek 1 =12.4 mg/dL, SDweek 2 =11.6 mg/dL, p=0.38) and Dexcom (SDduplicate = 11.1 mg/dL, SDweek 1 = 11.5 mg/dL, SDweek 2 =11.9 mg/dL, p=0.60).

Conclusions

Individual postprandial CGM responses to duplicate meals were unreliable in adults without diabetes. Personalized diet advice based on CGM measurements in adults without diabetes requires more reliable methods involving aggregated repeated measurements.

Ordered Eating and Its Effects on Various Postprandial Health Markers: A Systematic Review

OBJECTIVE

Aberrations in glucose, insulin, and other postprandial (PP) markers are common in obesity and cardiometabolic disorders. One potentially simple lifestyle/dietary modification to manage these issues is to change the order in which foods are consumed within meals. Carbohydrate exerts the largest effect on PP glucose, and there is some evidence that ingesting dietary fat or protein before carbohydrate delays gastric emptying of carbohydrate and reduces PP glucose. Additionally, certain dietary proteins may augment insulin release if ingested with carbohydrate, thereby improving blood glucose clearance. This review aimed to systematically evaluate evidence from acute experiments that modified the order in which foods were consumed in isocaloric meals.

METHODS

Outcomes of interest were PP glucose and insulin (including area under the curve for both), C-peptide, gut hormones, and perceptual responses. Three databases were searched (PubMed, Cochrane CENTRAL, Web of Science) in February 2022. Additionally, reference lists of identified reports were searched, and an author of several studies was consulted to verify that relevant literature was included. The review included acute interventions that administered isocaloric meals of the same foods but with foods eaten in different orders. Studies were not excluded based on participant characteristics.

RESULTS

Eleven reports were identified. All reports that assessed glucose and insulin showed a tendency toward lower levels, at least over parts of the PP period, by consuming carbohydrates last. GLP-1 tended to be higher in carbohydrate-last conditions, though this was only measured in a few studies. Perceptual responses (hunger, fullness, etc.) were not consistently different between conditions in two studies, but the certainty of evidence was very low.

CONCLUSIONS

Findings indicate that, at least acutely, there may be benefits to eating carbohydrate after vegetable and/or protein-rich foods. The most consistent effect (judged as moderate certainty) is that carbohydrate-last meal orders tend to lower blood glucose and insulin excursions.

A Randomized Controlled Pilot Study of the Food Order Behavioral Intervention in Prediabetes

(1) Background: Prior research in individuals with overweight/obesity and prediabetes or type 2 diabetes has shown that the ingestion of protein-rich food and non-starchy vegetables before concentrated carbohydrates (a carbohydrate-last food order) led to lower postprandial glucose excursions over 180 min, compared to eating the same foods in the reverse order. To expand upon this research, we sought to examine the feasibility and impact of carbohydrate-last food order behavioral intervention on glucose tolerance (GT), HbA1c, weight, and nutrient intake in adults with prediabetes in the real world over a 16-week span. (2) Methods: A total of 45 adults with overweight/obesity and prediabetes were randomized to receive 4-monthly standard nutritional counseling (C) or standard nutritional counseling plus carbohydrate-last food order counseling (FO) sessions (NCT# NCT03896360). (3) Results: The FO group decreased in body weight (-3.6 ± 5.7 lbs, p = 0.017), and trended toward lower HbA1c (-0.1 ± 0.2, p = 0.054). The C group weight trended lower (-2.6 ± 6.8 lbs, p = 0.102) without altering HbA1c (-0.03 ± 0.3, p = 0.605). GT was unchanged in both groups after 16 weeks. Changes in weight, HbA1c, and GT were similar between groups. Sensitivity analysis of pre-COVID participants showed significant weight loss in the FO group (-5.9 ± 5.3 lbs, p = 0.003) but not in C group (-1.0 ± 6.8 lbs, p = 0.608). After 16 weeks, the C group significantly reduced its daily intake of calories, fat, protein, and grains whereas the FO group increased its daily intake of vegetables and protein. There were 17 (94%) FO participants that reported high intervention adherence and 13 (72%) reported it was easy to eat protein/vegetables before carbohydrates. (4) Conclusions: A carbohydrate-last food order is a feasible behavioral strategy in individuals with prediabetes that improves diet quality, notably increasing protein and vegetable intake.

Influence of Meal Sequence and Number of Teeth Present on Nutrient Intake Status: A Cross-Sectional Study

Intake of fiber, as well as protein, and lipid preloading help to control postprandial glycemic elevation in people with type 2 diabetes and in healthy individuals. However, there are few studies on the awareness of meal sequence and nutrient intake status that consider oral conditions. This cross-sectional study aimed to determine the effects of meal sequences on nutrient intake status and whether these relationships were related to the number of teeth present. The subjects were recruited from the Medical and Dental Collaboration Center of Kanagawa Dental University Hospital between 2018 and 2021. Medical and dental examinations were performed, and a questionnaire was used to determine whether the diet consisted of vegetables, meat or fish, and carbohydrates in that order. Nutrient intake status was assessed using the brief-type self-administered diet history questionnaire. Data were collected from 238 participants. The group with awareness of meal sequence ingested increased nutrients such as n-3 fatty acids, total dietary fiber, calcium, and vitamin C. Saturated fatty acid intake increased in those with fewer teeth, while it was not significantly related to meal sequence. In conclusion, our results showed that meal sequence was associated with nutrient intake status. In addition, the intake of saturated fatty acids increased when many teeth were lost, regardless of meal sequence.

Sex differences in the acute effect of stair-climbing on postprandial blood glucose levels: A randomized controlled trial

Single, short stair climbing and descending (SCD) bouts of low to moderate intensity effectively lower postprandial blood glucose but previous reports have found conflicting results on interactions by sex during exercise. We hypothesize that SCD at a self-selected intensity will be equally effective at lowering postprandial blood glucose in males and females. Methods and Results: Thirty subjects (age: 23.8 (3.0) years) performed 0, 1, 3, and 10 min of SCD following consumption of a mixed meal. SCD was performed at a self-selected comfortable pace and all bouts ended at minute 28. Postprandial blood glucose was measured every 15 min for 1 h and analyzed as glucose over time, area under the curve (AUC), and incremental AUC (iAUC) using mixed-design ANOVAs with repeated measures. Although there was no interaction between sex and condition or time (p = .129 to .541) for glucose over time, AUC, or iAUC, there was a main effect for sex for glucose over time (p = .004) and AUC (p = .006), but not iAUC (p = .125). Females had higher blood glucose throughout each trial (22% (13 to 31%), p = .004) but both males' and females’ postprandial blood glucose was lowered following 10 min of SCD relative to the seated control condition. Conclusions: Males and females benefited equally from single, short SCD bouts of low to moderate intensity despite females having higher blood glucose at all time points. Previous findings of sex differences in the attenuating effect of exercise on postprandial blood glucose are likely due to the use of absolute workloads leading to varying relative intensities.

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SCD at a self-selected, comfortable pace for 3 min reduced postmeal blood glucose.

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Men and women benefit equally from SCD postprandial glucose attenuations.

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Previous sex differences were likely due to unequal relative intensity of exercise.

Rats learn to prefer the late-consumed flavor over the early-consumed flavor in a multi-flavored meal paired with oral glucose and corn oil

Conditioned flavor preference (CFP) is established by association: where a neutral flavor (conditioned stimulus, CS) is paired with orosensory and post-ingestive components of nutrients, including sugar and fat (unconditioned stimulus, US). A previous study reported that rats can learn to prefer flavors that they consumed earlier and later in a multi-flavored solution paired with an intragastric infusion of glucose, but they expressed only a preference for a late-consumed flavor when they were tested after feeding (Myers and Whitney, 2011). This paradigm can be a suitable rodent model to explain how humans acquire a selective preference for routinely late-served "dessert" foods and why these foods remain attractive even in the absence of hunger. Here, we examined whether oral glucose (Experiment 1) or fat (Experiment 2) acts as a US for flavor preference learning processes in this paradigm. In Experiment 1, adult female rats under food restriction were trained in 16 daily sessions with two distinct flavor CSs in succession per session; eight CS(+) sessions in which two distinct flavor CSs (early(+), late(+)) were sequentially presented for 8 min each with oral glucose (12%) as a US, and eight CS(-) sessions in which different CSs (early(-), late(-)) were unpaired with the US. In the 30-minute two-bottle choice test, rats preferred late(+) over late(-) only when tested 90 min after consumption of normal chow (fed test) but not after overnight deprivation (hungry test). Early(+) was not preferred over early(-) in both tests. Moreover, a significant preference for late(+) over early(+) was observed only in the fed test, which is a unique feature of oral glucose-CFP. These results indicate that taste sensations of oral glucose promote a rewarding effect of late-onset glucose nutrients. In Experiment 2, separate rats were trained with the same conditioning paradigm, but used a caloric matched fat solution (5.3% corn oil) for a US. The results showed that they expressed stronger preferences for early(+) and late(+) relative to their respective CS(-) flavors in both tests. Similar to Experiment 1, it was observed in the fed test that there was a preference for late(+) over early(+) in oral fat-CFP. Taken together, the present results suggest that routine timing arrangements can cause qualitative differences in conditioned preferences between multiple flavors within a sugar or fat-containing meal in rats, and that rats prefer the late-consumed flavor over the early-consumed flavor in the absence of hunger.

Illness perceptions as a mediator between emotional distress and management self-efficacy among Chinese Americans with type 2 diabetes

Objectives: Emotional distress and illness perceptions have been linked to patients' self-efficacy for diabetes management. This study, guided by Leventhal's Self-Regulatory Model, explores the direct effects of emotional distress (diabetes distress and depressive symptoms) on diabetes management self-efficacy, and the indirect effects through illness perceptions among Chinese Americans with type 2 diabetes (T2DM).Design: Data were obtained from a cross-sectional study of Chinese Americans with T2DM recruited from health fairs and other community settings (N = 155, 47.1% male, mean age 69.07 years). Data analyses including descriptive statistics, correlation, and PROCESS mediation models were used to examine the mediation effects of illness perceptions.Results: Diabetes distress and depressive symptoms had direct negative effects on self-efficacy. Perceived treatment control mediated the association between diabetes distress and self-efficacy, while none of the illness perceptions dimensions impacted the relationship between depressive symptoms and self-efficacy.Conclusion: Improved perceptions of treatment control can ameliorate diabetes distress and improve diabetes management self-efficacy among Chinese Americans. Health providers should elicit patients' illness perceptions as a first step in evaluating their diabetes management self-efficacy and provide appropriate culturally-tailored interventions.

Combination of Texture-Induced Oral Processing and Vegetable Preload Strategy Reduced Glycemic Excursion but Decreased Insulin Sensitivity

This study aimed to investigate the effect of the oral processing of vegetables induced by texture modification on acute postprandial glycemic response (GR) and insulin response (IR) when co-ingested and ingested prior to a rice meal. In a randomized crossover trial, 14 healthy female subjects consumed (1) co-ingestion of soft broccoli and rice (SR); (2) co-ingestion of hard broccoli and rice (HR); (3) soft broccoli prior to rice (S+R); (4) hard broccoli prior to rice (H+R); (5) rice (R). Postprandial GR and IR was compared between test meals over a period of 180-min, and the oral processing behaviors were measured for each test food samples. Hard broccoli was observed to have a higher mastication time and chews than soft broccoli. All the broccoli meals resulted in reduced incremental peak glucose (IPG) and an increased incremental area under the insulin curve in 180 min (iAUC_0–180) compared with R. The S+R curbed the IPG by 40% with comparable HOMA-IR AUC_0–180 compared with R, while the H+R elevated the HOMA-IR AUC_0–180 by 62% more than that of R. In conclusion, the soft broccoli intake prior to a rice meal effectively attenuated postprandial GR, without lowering insulin sensitivity as its hard counterpart did.

Efficacy of a meal sequence in patients with type 2 diabetes: a systematic review and meta-analysis

INTRODUCTION

This systematic review investigated the efficacy of a meal sequence, the carbohydrate-later meal pattern (CL), on type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, WHO International Clinical Trials Registry Platform, and ClinicalTrials.gov until April 2020 to perform meta-analyses using random-effects models. Primary outcomes were hemoglobin A1c (HbA1c) and quality of life. Secondary outcomes were plasma concentrations of glucose, insulin and incretin 120 min after a meal, and any adverse outcomes. The revised Cochrane risk-of-bias tool and Grading of Recommendations, Assessment, Development, and Evaluation approach were used to assess the quality of individual studies and the body of evidence, respectively. The present study was registered in the UMIN Clinical Trials Registry.

RESULTS

We included 230 participants in eight trials, including both trials that examined long-term changes (more than 2 months and less than 2 years) and short-term changes (in 2-hour postprandial values). CL resulted in a slight to no difference in HbA1c (mean difference (MD), -0.21% in the intervention group; 95% CI -0.44% to+0.03%), plasma glucose (MD,+4.94 mg/dL; 95% CI -8.34 mg/dL to +18.22 mg/dL), plasma insulin (MD, -3.63 μIU/mL; 95% CI -11.88 μIU/mL to +4.61 μIU/mL), plasma GLP-1 (MD, +0.43 pmol/L; 95% CI -0.69 pmol/L to +1.56 pmol/L), and plasma GIP (MD, -2.02 pmol/L; 95% CI -12.34 pmol/L to +8.31 pmol/L). All of these outcomes were of low-certainty evidence or very low-certainty evidence. None of the trials evaluated quality of life or adverse events.

CONCLUSIONS

There was no evidence for the potential efficacy of recommending CL beyond standard dietary advice on T2DM.

TRIAL REGISTRATION NUMBER

UMIN000039979.

Changing Meal Sequence Affects Glucose Excursions in Gestational Diabetes Mellitus

Studies on nutrient sequences during meals suggest that consuming carbohydrates last lowers postprandial glucose excursions more than consuming carbohydrates first. However, this phenomenon has not been studied in gestational diabetes mellitus (GDM). Ten women with GDM consumed the same caloric foods in different sequences over five successive days: (A) dish first, followed by carbohydrate and soup last; (B) carbohydrate first, followed by dish and soup last; (C) soup first, followed by dish and carbohydrate last; (D) three meals a day ad libitum; and (E) six meals a day as ad libitum. Continuous glucose monitoring (CGM) was used to assess diurnal glycemia. Decreases in mean glucose levels and the largest glucose levels in A were similar to group C. The peak glucose of breakfast and lunch in group B was more significant than in groups A and C. The B meal pattern showed more marked glycemic excursions than groups A and C. Increasing the number of meals reduced the peak glucose level and the glycemic excursions with the same total calories. Changing meal sequences or increasing the number of meals may reduce glycemic excursions in GDM. Our trial was registered retrospectively and the trial registration number is ChiCTR2200057044.

Acute Effects of Breakfast Fruits Meal Sequence and Postprandial Exercise on the Blood Glucose Level and DPP4 Activity among Type 2 Diabetes Mellitus Patients: A Pilot Study

OBJECTIVES

Type 2 diabetes mellitus (T2DM) is a major global public health issue. Diet and physical exercise are modifiable factors that influence the glycaemic status of patients with T2DM. We aimed to investigate the acute effects of breakfast fruits meal sequence and postprandial exercise on the blood glucose level and dipeptidyl peptidase 4 (DPP4) activity among type 2 diabetes mellitus patients.

METHODS

A randomized pilot study recruited patients with T2DM who attended two primary health care centres in Tasikmadu District, Karanganyar Regency, and Kartasura District, Sukoharjo Regency, Central Java, Indonesia, from July to October 2016. Eligible patients (4 men and 32 women) were randomly divided into four treatment groups. Venous blood samples were analyzed for fasting and one-hour postprandial blood glucose (FBG and 1 h PPG) levels and DPP4 activity. Blood glucose levels were measured using a routine hexokinase method, and serum DPP4 activity was determined spectrophotometrically after incubation with the Gly-Pro-p-nitroanilide substrate.

RESULTS

Fruits last meal decreased FBG level whilst fruits first meal did not significantly decrease 1 h PPG level. Both treatments had no acute effects on DPP4 activity but the addition of postprandial exercise helped lower DPP4 activity. Fruit last and first meals showed significant opposite effects on mean changes of FBG level (p < 0.05).

CONCLUSIONS

This preliminary report of fruits meal sequence is potentially involved in acute regulation of blood glucose levels and that it might be independent of DPP4 activity in Indonesian patients with T2DM. Moreover, postprandial exercise may be an important intervention for T2DM through the mediation of DPP4 but has no acute effects on the regulation of blood glucose levels. Further studies are required to investigate whether or not different types of fruits and longer treatment intervals can affect blood glucose levels and DPP4 activity differently. This study also gives an insight into the feasibility of conducting food order modification with or without the combination of postprandial exercise in a primary health setting for our next studies.

Novel trends and concepts in the nutritional management of glycemia in type 2 diabetes mellitus-beyond dietary patterns: a narrative review

A variety of eating patterns are recommended by international guidelines to help people with type 2 diabetes mellitus (T2DM) achieve general health and glycemia goals. Apart from eating patterns, there is evidence that other approaches related to the everyday application of dietary advice, such as meal frequency, breakfast consumption, daily carbohydrate distribution, and order of food consumption during meals, have significant effects on glycemia management. The aims of this review were to examine published diabetes nutrition guidelines concerning specific recommendations with regard to the above approaches, as well as to review evidence from studies that have investigated their effect on glycemia in T2DM. The data suggest that eating breakfast regularly, consuming most carbohydrates at lunch, avoiding large dinners late at night, and applying the carbohydrate-last meal pattern are effective practices towards better nutritional management of T2DM.

The Roles of Carbohydrate Response Element Binding Protein in the Relationship between Carbohydrate Intake and Diseases

Carbohydrates are macronutrients that serve as energy sources. Many studies have shown that carbohydrate intake is nonlinearly associated with mortality. Moreover, high-fructose corn syrup (HFCS) consumption is positively associated with obesity, cardiovascular disease, and type 2 diabetes mellitus (T2DM). Accordingly, products with equal amounts of glucose and fructose have the worst effects on caloric intake, body weight gain, and glucose intolerance, suggesting that carbohydrate amount, kind, and form determine mortality. Understanding the role of carbohydrate response element binding protein (ChREBP) in glucose and lipid metabolism will be beneficial for elucidating the harmful effects of high-fructose corn syrup (HFCS), as this glucose-activated transcription factor regulates glycolytic and lipogenic gene expression. Glucose and fructose coordinately supply the metabolites necessary for ChREBP activation and de novo lipogenesis. Chrebp overexpression causes fatty liver and lower plasma glucose levels, and ChREBP deletion prevents obesity and fatty liver. Intestinal ChREBP regulates fructose absorption and catabolism, and adipose-specific Chrebp-knockout mice show insulin resistance. ChREBP also regulates the appetite for sweets by controlling fibroblast growth factor 21, which promotes energy expenditure. Thus, ChREBP partly mimics the effects of carbohydrate, especially HFCS. The relationship between carbohydrate intake and diseases partly resembles those between ChREBP activity and diseases.

The Role of Protein and Fat Intake on Insulin Therapy in Glycaemic Control of Paediatric Type 1 Diabetes: A Systematic Review and Research Gaps

Carbohydrate counting (CHC) is the established form of calculating bolus insulin for meals in children with type 1 diabetes (T1DM). With the widespread use of continuous glucose monitoring (CGM) observation time has become gapless. Recently, the impact of fat, protein and not only carbohydrates on prolonged postprandial hyperglycaemia have become more evident to patients and health-care professionals alike. However, there is no unified recommendation on how to calculate and best administer additional bolus insulin for these two macronutrients. The aim of this review is to investigate: the scientific evidence of how dietary fat and protein influence postprandial glucose levels; current recommendations on the adjustment of bolus insulin; and algorithms for insulin application in children with T1DM. A PubMed search for all articles addressing the role of fat and protein in paediatric (sub-)populations (<18 years old) and a mixed age population (paediatric and adult) with T1DM published in the last 10 years was performed. Conclusion: Only a small number of studies with a very low number of participants and high degree of heterogeneity was identified. While all studies concluded that additional bolus insulin for (high) fat and (high) protein is necessary, no consensus on when dietary fat and/or protein should be taken into calculation and no unified algorithm for insulin therapy in this context exists. A prolonged postprandial observation time is necessary to improve individual metabolic control. Further studies focusing on a stratified paediatric population to create a safe and effective algorithm, taking fat and protein into account, are necessary.

Dietary Control of Inflammation and Resolution

The healing of any injury requires a dynamic balance of initiation and resolution of inflammation. This hypothesis-generating review presents an overview of the various nutrients that can act as signaling agents to modify the metabolic responses essential for the optimal healing of injury-induced inflammation. In this hypothesis-generating review, we describe a defined nutritional program consisting of an integrated interaction of a calorie-restricted anti-inflammatory diet coupled with adequate levels of omega-3 fatty acids and sufficient levels of dietary polyphenols that can be used in clinical trials to treat conditions associated with insulin resistance. Each dietary intervention works in an orchestrated systems-based approach to reduce, resolve, and repair the tissue damage caused by any inflammation-inducing injury. The orchestration of these specific nutrients and their signaling metabolites to facilitate healing is termed the Resolution Response. The final stage of the Resolution Response is the activation of intracellular 5' adenosine monophosphate-activated protein kinase (AMPK), which is necessary to repair tissue damaged by the initial injury-induced inflammation. The dietary optimization of the Resolution Response can be personalized to the individual by using standard blood markers. Once each of those markers is in their appropriate ranges, activation of intracellular AMPK will be facilitated. Finally, we outline how the resulting activation of AMPK will affect a diverse number of other intercellular signaling systems leading to an extended healthspan.

Eating Speed and Incidence of Diabetes in a Japanese General Population: ISSA-CKD

Background: We investigated whether eating speed was associated with the incidence of diabetes in a Japanese general population. Methods: A total of 4853 Japanese individuals without diabetes at baseline were analyzed. Self-reported eating speed was categorized as slow, medium, and fast on the basis of questionnaire responses. The study outcome was the incidence of diabetes. Results: After an average follow-up period of 5.1 years, 234 individuals developed diabetes. The incidence of diabetes per 1000 person-years was 4.9 in the slow eating speed group, 8.8 in the medium eating speed group, and 12.5 in the fast eating speed group, respectively (*** p < 0.001 for trend). The HRs were 1.69 (95%CI 0.94–3.06) for the medium eating speed and 2.08 (95%CI 1.13–3.84) for the fast eating speed, compared to the slow eating speed (* p = 0.014 for trend) after adjustment for age, gender, smoking status, drinking, exercise, obesity, hypertension, and dyslipidemia. Conclusion: Faster eating speed increased a risk for the incidence of diabetes in a general Japanese population.

Dietary Aspects to Incorporate in the Creation of a Mobile Image-Based Dietary Assessment Tool to Manage and Improve Diabetes

Diabetes is the seventh leading cause of death in United States. Dietary intake and behaviors are essential components of diabetes management. Growing evidence suggests dietary components beyond carbohydrates may critically impact glycemic control. Assessment tools on mobile platforms have the ability to capture multiple aspects of dietary behavior in real-time throughout the day to inform and improve diabetes management and insulin dosing. The objective of this narrative review was to summarize evidence related to dietary behaviors and composition to inform a mobile image-based dietary assessment tool for managing glycemic control of both diabetes types (type 1 and type 2 diabetes). This review investigated the following topics amongst those with diabetes: (1) the role of time of eating occasion on indicators of glycemic control; and (2) the role of macronutrient composition of meals on indicators of glycemic control. A search for articles published after 2000 was completed in PubMed with the following sets of keywords “diabetes/diabetes management/diabetes prevention/diabetes risk”, “dietary behavior/eating patterns/temporal/meal timing/meal frequency”, and “macronutrient composition/glycemic index”. Results showed eating behaviors and meal macronutrient composition may affect glycemic control. Specifically, breakfast skipping, late eating and frequent meal consumption might be associated with poor glycemic control while macronutrient composition and order of the meal could also affect glycemic control. These factors should be considered in designing a dietary assessment tool, which may optimize diabetes management to reduce the burden of this disease.

Gut-Based Strategies to Reduce Postprandial Glycaemia in Type 2 Diabetes

Postprandial glycemic control is an important target for optimal type 2 diabetes management, but is often difficult to achieve. The gastrointestinal tract plays a major role in modulating postprandial glycaemia in both health and diabetes. The various strategies that have been proposed to modulate gastrointestinal function, particularly by slowing gastric emptying and/or stimulating incretin hormone GLP-1, are summarized in this review.

Toxic AGEs (TAGE) theory: a new concept for preventing the development of diseases related to lifestyle

BACKGROUND

The habitual excessive intake of sugar (i.e., sucrose and high-fructose corn syrup), which has been implicated in the onset of diabetes mellitus, induces excessive production of glyceraldehyde, a metabolite produced during glucose and fructose metabolism, in hepatocytes, neuronal cells, and cardiomyocytes.

MAIN TEXT

Toxic advanced glycation end-products (toxic AGEs, TAGE) are formed from reactions between glyceraldehyde and intracellular proteins, and their accumulation contributes to various cellular disorders. TAGE leakage from cells affects the surrounding cells and increases serum TAGE levels, promoting the onset and/or development of lifestyle-related diseases (LSRD). Therefore, serum TAGE levels have potential as a novel biomarker for predicting the onset and/or progression of LSRD, and minimizing the effects of TAGE might help to prevent the onset and/or progression of LSRD. Serum TAGE levels are closely related to LSRD associated with the excessive ingestion of sugar and/or dietary AGEs.

CONCLUSIONS

The TAGE theory is also expected to open new perspectives for research into numerous other diseases.

The Future of Shift Work: Circadian Biology Meets Personalised Medicine and Behavioural Science

Shift work is commonplace in modern societies, and shift workers are predisposed to the development of numerous chronic diseases. Disruptions to the circadian systems of shift workers are considered important contributors to the biological dysfunction these people frequently experience. Because of this, understanding how to alter shift work and zeitgeber (time cue) schedules to enhance circadian system function is likely to be key to improving the health of shift workers. While light exposure is the most important zeitgeber for the central clock in the circadian system, diet and exercise are plausible zeitgebers for circadian clocks in many tissues. We know little about how different zeitgebers interact and how to tailor zeitgeber schedules to the needs of individuals; however, in this review we share some guidelines to help shift workers adapt to their work schedules based on our current understanding of circadian biology. We focus in particular on the importance of diet timing and composition. Going forward, developments in phenotyping and "envirotyping" methods may be important to understanding how to optimise shift work. Non-invasive, multimodal, comprehensive phenotyping using multiple sources of time-stamped data may yield insights that are critical to the care of shift workers. Finally, the impact of these advances will be reduced without modifications to work environments to make it easier for shift workers to engage in behaviours conducive to their health. Integrating findings from behavioural science and ergonomics may help shift workers make healthier choices, thereby amplifying the beneficial effects of improved lifestyle prescriptions for these people.

Dietary instructions focusing on meal-sequence and nutritional balance for prediabetes subjects: An exploratory, cluster-randomized, prospective, open-label, clinical trial

BACKGROUND

Although lifestyle modifications are known to be effective in type 2 diabetes (T2D) as well as in prediabetes, adherence to a healthy diet is difficult for some, and interventions of lifestyle modifications need to be revised occasionally. Meal sequence has been gaining attention as a part of a healthy diet among T2D individuals to improve glycemia and body weight. In addition, a dietary instruction program, SMART Washoku®, which can help individuals to consume a more nutritionally balanced diet, has been developed.

METHODS

The current exploratory trial was designed to examine the effects of dietary instructions focusing on meal sequence and nutritional balance in individuals with prediabetes in the Japanese national health check-up and guidance program. Participants were cluster-randomized into three groups: Group A, receiving a conventional health guidance program (n = 11); Group B, receiving health guidance with dietary instructions focusing on meal sequence (n = 18); and Group C, receiving health guidance with dietary instructions focusing on nutritional balance (n = 13). Participants received health guidance education and various measurements before and 6 months after the instructions.

RESULTS

Body weight in Group B was significantly reduced compared to that in Group A, with similar adherence, while the effects on glycemia were similar between the two Groups. Body weight reduction was greater in Group C compared to that in Group A, although adherence in Group C was significantly lower than that in Group A.

CONCLUSION

The group receiving health guidance with dietary instructions focusing on meal sequence exhibited similar adherence and greater reduction in body weight than the group receiving conventional health guidance.

Optimizing Postprandial Glucose Management in Adults With Insulin-Requiring Diabetes: Report and Recommendations

Faster-acting insulins, new noninsulin drug classes, more flexible insulin-delivery systems, and improved continuous glucose monitoring devices offer unprecedented opportunities to improve postprandial glucose (PPG) management and overall care for adults with insulin-treated diabetes. These developments led the Endocrine Society to convene a working panel of diabetes experts in December 2018 to assess the current state of PPG management, identify innovative ways to improve self-management and quality of life, and align best practices to current and emerging treatment and monitoring options. Drawing on current research and collective clinical experience, we considered the following issues for the ∼200 million adults worldwide with type 1 and insulin-requiring type 2 diabetes: (i) the role of PPG management in reducing the risk of diabetes complications; (ii) barriers preventing effective PPG management; (iii) strategies to reduce PPG excursions and improve patient quality of life; and (iv) education and clinical tools to support endocrinologists in improving PPG management. We concluded that managing PPG to minimize or prevent diabetes-related complications will require elucidating fundamental questions about optimal ways to quantify and clinically assess the metabolic dysregulation and consequences of the abnormal postprandial state in diabetes and recommend research strategies to address these questions. We also identified practical strategies and tools that are already available to reduce barriers to effective PPG management, optimize use of new and emerging clinical tools, and improve patient self-management and quality of life.

Nutritional strategies in managing postmeal glucose for type 2 diabetes: A narrative review

Medical Nutrition Therapy (MNT) plays an essential role in overall glycemic management. Less focus is given on managing postmeal hyperglycemia despite the facts that, it is a common feature of Type 2 Diabetes (T2D). The purpose of this narrative review is to provide a comprehensive understanding of the existing literature on the nutritional approaches to improve postmeal hyperglycemia in patients with T2D. We searched multiple databases for the studies examining the nutritional approaches to manage postmeal glucose in patients with T2D. We included studies that involve human trials that were published in English for the past 10 years. Our review of the current literature indicates that the postmeal hyperglycemia can be improved with four nutritional approaches. These approaches include (i) utilizing the appropriate amount and selecting the right type of carbohydrates, (ii) using specific types of dietary protein, (iii) manipulating the meal timing and orders and (iv) others (promoting postmeal physical activity, incorporating diabetes-specific formula and certain functional foods). The potential mechanisms underlying these approaches are discussed and the identified gaps warranted further research. This array of nutritional strategies provide a set of options for healthcare professionals to facilitate patients with T2D in achieving the optimal level of postmeal glucose.

Postprandial glucose, insulin and incretin responses differ by test meal macronutrient ingestion sequence (PATTERN study)

BACKGROUND

Previous studies have shown that the sequential order of consuming different food components significantly impacts postprandial glucose and insulin excursions in prediabetes and type 2 diabetes, but the causative mechanisms in healthy humans remain ill-defined.

OBJECTIVE

Using a typical Asian meal comprising vegetables, protein (chicken breast), and carbohydrate (white rice), the aim of this study was to examine the effect of food intake sequence on postprandial glucose, insulin and incretin secretions in healthy adults.

DESIGN

Sixteen healthy Chinese adults participated in a randomized, controlled, crossover meal trial. Subjects consumed in random order 5 experimental isocaloric meals that differed in the food intake sequence of vegetables, protein and carbohydrate. Glucose, insulin, incretins and satiety markers were measured over 3 h.

RESULTS

There were significant food intake sequence × time interaction effects on plasma glucose, insulin, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) concentrations (P < 0.001). In comparison with rice consumed first followed by vegetable and meat (R-VM), the overall postprandial glucose response was significantly attenuated after the food intake sequence of vegetable first, followed by meat and rice (V-MR) or meat first, followed by vegetable and rice (M-VR) or vegetable first followed by meat and rice (V-M-R) or vegetable, meat and rice consumed together (VMR). The insulin iAUC (0-60) was significant lower after V-M-R than M-VR, VMR and R-VM. V-M-R food intake sequence stimulated higher GLP-1 release than other meal sequences. However, GIP response was lower after V-MR and V-M-R than M-VR and R-MR food intake sequences.

CONCLUSIONS

Food macronutrient intake sequence can considerably influence its glycemic, insulinemic and incretin responses. V-M-R food intake sequence attenuates the glycemic response to a greater degree with accentuated GLP-1 stimulation without any increased demand for insulin. The sequence of food intake has great potential as a novel and simple behavioral strategy to modulate glycemic response in healthy adults. The trial was registered at clinicaltrials.gov as NCT03533738.

Insulin in Type 1 and Type 2 Diabetes-Should the Dose of Insulin Before a Meal be Based on Glycemia or Meal Content?

The aim of this review was to investigate existing guidelines and scientific evidence on determining insulin dosage in people with type 1 and type 2 diabetes, and in particular to check whether the prandial insulin dose should be calculated based on glycemia or the meal composition, including the carbohydrates, protein and fat content in a meal. By exploring the effect of the meal composition on postprandial glycemia we demonstrated that several factors may influence the increase in glycemia after the meal, which creates significant practical difficulties in determining the appropriate prandial insulin dose. Then we reviewed effects of the existing insulin therapy regimens on glycemic control. We demonstrated that in most existing algorithms aimed at calculating prandial insulin doses in type 1 diabetes only carbohydrates are counted, whereas in type 2 diabetes the meal content is often not taken into consideration. We conclude that prandial insulin doses in treatment of people with diabetes should take into account the pre-meal glycemia as well as the size and composition of meals. However, there are still open questions regarding the optimal way to adjust a prandial insulin dose to a meal and the possible benefits for people with type 1 and type 2 diabetes if particular parameters of the meal are taken into account while calculating the prandial insulin dose. The answers to these questions may vary depending on the type of diabetes.

The impact of food order on postprandial glycaemic excursions in prediabetes

Data suggest that nutrient order during a meal significantly impacts postprandial glucose and insulin excursions in type 2 diabetes, while its effects in prediabetes have not been reported. Fifteen participants with prediabetes consumed the same meal on 3 days in random order: carbohydrate first, followed 10 minutes later by protein and vegetables (CF); protein and vegetables first, followed 10 minutes later by carbohydrate (PVF); or vegetables first followed by protein and carbohydrate (VF). Blood was sampled for glucose and insulin measurements at 0, 30, 60, 90, 120, 150 and 180 minutes. Incremental glucose peaks were similarly attenuated by >40% in the PVF and VF meal conditions compared with CF. The incremental area under the curve for glucose was 38.8% lower following the PVF meal order, compared with CF, and postprandial insulin excursions were significantly lower in the VF meal condition compared with CF. The CF meal pattern showed marked glycaemic variability whereas glucose levels were stable in the PVF and VF meal conditions. Food order presents a novel, simple behavioural strategy to reduce glycaemic excursions in prediabetes.

Impact of Nutrient Type and Sequence on Glucose Tolerance: Physiological Insights and Therapeutic Implications

Pharmacological and dietary interventions targeting postprandial glycemia have proved effective in reducing the risk for type 2 diabetes and its cardiovascular complications. Besides meal composition and size, the timing of macronutrient consumption during a meal has been recently recognized as a key regulator of postprandial glycemia. Emerging evidence suggests that premeal consumption of non-carbohydrate macronutrients (i.e., protein and fat "preloads") can markedly reduce postprandial glycemia by delaying gastric emptying, enhancing glucose-stimulated insulin release, and decreasing insulin clearance. The same improvement in glucose tolerance is achievable by optimal timing of carbohydrate ingestion during a meal (i.e., carbohydrate-last meal patterns), which minimizes the risk of body weight gain when compared with nutrient preloads. The magnitude of the glucose-lowering effect of preload-based nutritional strategies is greater in type 2 diabetes than healthy subjects, being comparable and additive to current glucose-lowering drugs, and appears sustained over time. This dietary approach has also shown promising results in pathological conditions characterized by postprandial hyperglycemia in which available pharmacological options are limited or not cost-effective, such as type 1 diabetes, gestational diabetes, and impaired glucose tolerance. Therefore, preload-based nutritional strategies, either alone or in combination with pharmacological treatments, may offer a simple, effective, safe, and inexpensive tool for the prevention and management of postprandial hyperglycemia. Here, we survey these novel physiological insights and their therapeutic implications for patients with diabetes mellitus and altered glucose tolerance.