The Efficacy of Exercise Training for Cutaneous Microvascular Reactivity in the Foot in People with Diabetes and Obesity: Secondary Analyses from a Randomized Controlled Trial.

It is unclear if cutaneous microvascular dysfunction associated with diabetes and obesity can be ameliorated with exercise. We investigated the effect of 12-weeks of exercise training on cutaneous microvascular reactivity in the foot. Thirty-three inactive adults with type 2 diabetes and obesity (55% male, 56.1 ± 7.9 years, BMI: 35.8 ± 5, diabetes duration: 7.9 ± 6.3 years) were randomly allocated to 12-weeks of either (i) moderate-intensity continuous training [50−60% peak oxygen consumption (VO2peak), 30−45 min, 3 d/week], (ii) low-volume high-intensity interval training (90% VO2peak, 1−4 min, 3 d/week) or (iii) sham exercise placebo. Post-occlusive reactive hyperaemia at the hallux was determined by laser-Doppler fluxmetry. Though time to peak flux post-occlusion almost halved following moderate intensity exercise, no outcome measure reached statistical significance (p > 0.05). These secondary findings from a randomised controlled trial are the first data reporting the effect of exercise interventions on cutaneous microvascular reactivity in the foot in people with diabetes. A period of 12 weeks of moderate-intensity or low-volume high-intensity exercise may not be enough to elicit functional improvements in foot microvascular reactivity in adults with type 2 diabetes and obesity. Larger, sufficiently powered, prospective studies are necessary to determine if additional weight loss and/or higher exercise volume is required.

Degree of adiposity and obesity severity is associated with cutaneous microvascular dysfunction in type 2 diabetes.

BACKGROUNDS AND AIMS: Obesity and diabetes independently contribute to cutaneous microvascular dysfunction via pathological processes that are not fully understood. We sought to determine if obesity severity is associated with cutaneous microvascular dysfunction and measures of peripheral arterial disease in adults with type 2 diabetes in cross-sectional observational study design. METHODS AND RESULTS: Primary outcomes were post-occlusive reactive hyperaemia as determined by laser-Doppler fluxmetry (peak flux post-occlusion, time to peak flux post-occlusion, peak as a percentage of baseline, and area under the curve [AuC] index post-occlusion to pre-occlusion). Secondary outcomes were ankle- and toe-brachial indices (ABI and TBI) and systolic toe pressure. Thirty-six participants (20 men, 16 women) with mean age 55 ± 8 years, BMI of 36 ± 5 kg/m2 and duration of diabetes 8 ± 6 years underwent measurements. After adjusting for age and duration of diabetes, SAT and total percentage body fat were able to explain 29% (p = 0.001) and 20% (p = 0.01) of variance of AuC index models, as well as 29% (p = 0.02) and 18% (p = 0.02) of peak as a percentage of baseline models, respectively. Though TBI demonstrated moderate, significant correlations with SAT (r:0.37, p = 0.04) and total percentage body fat (r:0.39, p = 0.03), these were not upheld by regression analyses. Neither ABI nor systolic toe pressure significantly correlated with any measure of adiposity or obesity. CONCLUSION: These findings demonstrate impairment in cutaneous microvascular function related to adiposity and obesity severity in adults with type 2 diabetes, suggesting that obesity may pathologically effect cutaneous microvascular function in the absence of overt macrovascular disease, warranting further investigation.

The Effect of a Novel Low-Volume Aerobic Exercise Intervention on Liver Fat in Type 2 Diabetes: A Randomized Controlled Trial.

OBJECTIVE: The aim of this study was to examine the effect of a novel low-volume high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), or placebo (PLA) intervention on liver fat, glycemia, and cardiorespiratory fitness using a randomized placebo-controlled design. RESEARCH DESIGN AND METHODS: Thirty-five inactive adults (age 54.6 ± 1.4 years, 54% male; BMI 35.9 ± 0.9 kg/m2) with obesity and type 2 diabetes were randomized to 12 weeks of supervised MICT (n = 12) at 60% VO2peak for 45 min, 3 days/week; HIIT (n = 12) at 90% VO2peak for 4 min, 3 days/week; or PLA (n = 11). Liver fat percentage was quantified through proton MRS. RESULTS: Liver fat reduced in MICT (-0.9 ± 0.7%) and HIIT (-1.7 ± 1.1%) but increased in PLA (1.2 ± 0.5%) (P = 0.046). HbA1c improved in MICT (-0.3 ± 0.3%) and HIIT (-0.3 ± 0.3%) but not in PLA (0.5 ± 0.2%) (P = 0.014). Cardiorespiratory fitness improved in MICT (2.3 ± 1.2 mL/kg/min) and HIIT (1.1 ± 0.5 mL/kg/min) but not in PLA (-1.5 ± 0.9 mL/kg/min) (P = 0.006). CONCLUSIONS: MICT or a low-volume HIIT approach involving 12 min of weekly high-intensity aerobic exercise may improve liver fat, glycemia, and cardiorespiratory fitness in people with type 2 diabetes in the absence of weight loss. Further studies are required to elucidate the relationship between exercise-induced reductions in liver fat and improvements in glycemia.

The effect of low-volume high-intensity interval training on cardiovascular health outcomes in type 2 diabetes: A randomised controlled trial.

BACKGROUND: Low-volume high-intensity interval training (HIIT) may be a time-efficient strategy that leads to similar or superior improvements in cardiorespiratory fitness (CRF) and cardiovascular disease (CVD) risk factors when compared with moderate-intensity continuous training (MICT). Our study investigated the effect of low-volume HIIT or MICT versus sham placebo-control (PLA) on central arterial stiffness, hemodynamic responses, and CVD risk factors in adults with obesity and type 2 diabetes (T2D). METHODS: Eligible participants were previously inactive adults with obesity and T2D. Individuals were randomly allocated to: i) HIIT (1 × 4 min cycling at 90% peak oxygen consumption [V̇O2peak]); ii) MICT (45 min of cycling at 60% VO2peak); or PLA. Training groups exercised thrice weekly for 12 weeks. Central arterial stiffness, hemodynamics and CVD risk factors were assessed at baseline and post-intervention. Analysis of covariance (ANCOVA) was used to examine changes following HIIT, MICT and PLA. RESULTS: Thirty-five participants (age: 55.1 ± 1.4 years, BMI: 36.1 ± 0.8 kg/m2) completed the study. A significant intervention effect was found for changes in pulse wave velocity (PWV) (p = .03), which reduced with HIIT (-0.3 ± 0.9 m/s) and MICT (-0.1 ± 1.1 m/s) but increased with PLA (0.8 ± 1.6 m/s). There was a significant intervention effect for changes in V̇O2peak (p < .01), glycosylated hemoglobin (p = .03), systolic blood pressure (p < .01), and waist circumference (p = .03), which all improved following MICT or HIIT but not PLA; there was no difference between MICT and HIIT. CONCLUSIONS: Twelve minutes of low-volume HIIT per week leads to improvements in central arterial stiffness and cardiovascular health in inactive individuals with obesity and T2D.

Effect of a high-egg diet on cardiometabolic risk factors in people with type 2 diabetes: the Diabetes and Egg (DIABEGG) Study-randomized weight-loss and follow-up phase.

Background: Some country guidelines recommend that people with type 2 diabetes (T2D) limit their consumption of eggs and cholesterol. Our previously published 3-mo weight-maintenance study showed that a high-egg (≥12 eggs/wk) diet compared with a low-egg diet (<2 eggs/wk) did not have adverse effects on cardiometabolic risk factors in adults with T2D. Objective: The current study follows the previously published 3-mo weight-maintenance study and assessed the effects of the high-egg compared with the low-egg diets as part of a 3-mo weight-loss period, followed by a 6-mo follow-up period for a total duration of 12 mo. Design: Participants with prediabetes or T2D (n = 128) were prescribed a 3-mo daily energy restriction of 2.1 MJ and a macronutrient-matched diet and instructed on specific types and quantities of foods to be consumed, with an emphasis on replacing saturated fats with monounsaturated and polyunsaturated fats. Participants were followed up at the 9- and 12-mo visits. Results: From 3 to 12 mo, the weight loss was similar (high-egg compared with low-egg diets: -3.1 ± 6.3 compared with -3.1 ± 5.2 kg; P = 0.48). There were no differences between groups in glycemia (plasma glucose, glycated hemoglobin, 1,5-anhydroglucitol), traditional serum lipids, markers of inflammation (high-sensitivity C-reactive protein, interleukin 6, soluble E-selectin), oxidative stress (F2-isoprostanes), or adiponectin from 3 to 12 mo or from 0 to 12 mo. Conclusions: People with prediabetes or T2D who consumed a 3-mo high-egg weight-loss diet with a 6-mo follow-up exhibited no adverse changes in cardiometabolic markers compared with those who consumed a low-egg weight-loss diet. A healthy diet based on population guidelines and including more eggs than currently recommended by some countries may be safely consumed. This trial is registered at http://www.anzctr.org.au/ as ACTRN12612001266853.

Comparison of an electronic versus traditional food diary for assessing dietary intake-A validation study.

BACKGROUND: Paper-based estimated food diaries are often used in research to collect dietary data, despite this method being burdensome for both participants and researchers. Such food diaries are often time consuming, labour intensive, and rely on participant literacy and therefore may lead to greater rates of under-reporting. METHODS: This study assessed the validity of the 'Boden Food Plate', a novel web-based electronic application, compared to a paper-based three-day estimated food diary. Participants were also asked to rate their satisfaction with the new electronic diary. Sixty-seven participants with overweight or obesity completed both the electronic and paper-based diaries at two different time-points. RESULTS: Baseline BMI of participants (mean±standard deviation (SD)) was 30.4±2.9kg/m2, body weight was 87.6±13.4kg, and age was 42.3±7.7years. Fifty four percent (n=41) of the cohort were female. Bland Altman plots for total energy, and percentage of total energy intake from fat, carbohydrate, and protein, indicated wide limits of agreement between the two methods of dietary data collection, and in some analyses there were a few cases that did not lie within the 95% confidence intervals. Approximately 70% of participants rated the electronic food diary as easier to use and more fun when compared to the traditional paper-based estimated food diary. CONCLUSION: Innovative and visual dietary collection applications such as the 'Boden Food Plate' provide an enjoyable and interactive means of measuring nutritional intake in a time efficient manner. Further validation studies incorporating micronutrient analysis and to improve the applications validity are warranted.

Effect of aerobic exercise training dose on liver fat and visceral adiposity.

BACKGROUND & AIMS: Aerobic exercise reduces liver fat and visceral adipose tissue (VAT). However, there is limited data from randomized trials to inform exercise programming recommendations. This study examined the efficacy of commonly prescribed exercise doses for reducing liver fat and VAT using a randomized placebo-controlled design. METHODS: Inactive and overweight/obese adults received 8 weeks of either; i) low to moderate intensity, high volume aerobic exercise (LO:HI, 50% VO 2peak, 60 min, 4d/week); ii) high intensity, low volume aerobic exercise (HI:LO, 70% VO 2peak, 45 min, 3d/week); iii) low to moderate intensity, low volume aerobic exercise (LO:LO, 50% VO 2peak, 45 min, 3d/week); or iv) placebo (PLA). Liver fat (spectroscopy) and VAT (magnetic resonance imaging) were measured before and after intervention. RESULTS: Forty-seven of the 48 (n = 12 in each group) participants completed the trial. There were no serious adverse events. There was a significant change in group × time interaction in liver fat, which reduced in HI:LO by 2.38 ± 0.73%, in LO:HI by 2.62 ± 1.00%, and in LO:LO by 0.84 ± 0.47% but not in PLA (increase of 1.10 ± 0.62%) (p = 0.04). There was a significant reduction in VAT in HI:LO (-258.38 ± 87.78 cm(3)), in LO:HI (-386.80 ± 119.5 cm(3)), and in LO:LO (-212.96 ± 105.54 cm(3)), but not in PLA (92.64 ± 83.46 cm(3)) (p = 0.03). There were no significant differences between the dose or intensity of the exercise regimen and reductions in liver fat or VAT (p > 0.05). CONCLUSION: The study found no difference in efficacy of liver fat reduction by either aerobic exercise dose or intensity. All of the aerobic exercise regimens employed reduced liver fat and VAT by a small amount without clinically significant weight loss.

The effect of a high-egg diet on cardiovascular risk factors in people with type 2 diabetes: the Diabetes and Egg (DIABEGG) study-a 3-mo randomized controlled trial.

BACKGROUND: Previously published research that examined the effects of high egg consumption in people with type 2 diabetes (T2D) produced conflicting results leading to recommendations to limit egg intake. However, people with T2D may benefit from egg consumption because eggs are a nutritious and convenient way of improving protein and micronutrient contents of the diet, which have importance for satiety and weight management. OBJECTIVE: In this randomized controlled study, we aimed to determine whether a high-egg diet (2 eggs/d for 6 d/wk) compared with a low-egg diet (<2 eggs/wk) affected circulating lipid profiles, in particular high-density lipoprotein (HDL) cholesterol, in overweight or obese people with prediabetes or T2D. DESIGN: A total of 140 participants were randomly assigned to one of the 2 diets as part of a 3-mo weight maintenance study. Participants attended the clinic monthly and were instructed on the specific types of foods and quantities to be consumed. RESULTS: There was no significant difference in the change in HDL cholesterol from screening to 3 mo between groups; the mean difference (95% CI) between high- and low-egg groups was +0.02 mmol/L (-0.03, 0.08 mmol/L; P = 0.38). No between-group differences were shown for total cholesterol, low-density lipoprotein cholesterol, triglycerides, or glycemic control. Both groups were matched for protein intake, but the high-egg group reported less hunger and greater satiety postbreakfast. Polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) intakes significantly increased from baseline in both groups. CONCLUSIONS: High egg consumption did not have an adverse effect on the lipid profile of people with T2D in the context of increased MUFA and PUFA consumption. This study suggests that a high-egg diet can be included safely as part of the dietary management of T2D, and it may provide greater satiety. This trial was registered at the Australia New Zealand Clinical Trials Registry (http://www.anzctr.org.au/) as ACTRN12612001266853.

Continuous exercise but not high intensity interval training improves fat distribution in overweight adults.

OBJECTIVE: The purpose of this study was to assess the effect of high intensity interval training (HIIT) versus continuous aerobic exercise training (CONT) or placebo (PLA) on body composition by randomized controlled design. METHODS: Work capacity and body composition (dual-energy X-ray absorptiometry) were measured before and after 12 weeks of intervention in 38 previously inactive overweight adults. RESULTS: There was a significant group × time interaction for change in work capacity (P < 0.001), which increased significantly in CONT (23.8 ± 3.0%) and HIIT (22.3 ± 3.5%) but not PLA (3.1 ± 5.0%). There was a near-significant main effect for percentage trunk fat, with trunk fat reducing in CONT by 3.1 ± 1.6% and in PLA by 1.1 ± 0.4%, but not in HIIT (increase of 0.7 ± 1.0%) (P = 0.07). There was a significant reduction in android fat percentage in CONT (2.7 ± 1.3%) and PLA (1.4 ± 0.8%) but not HIIT (increase of 0.8 ± 0.7%) (P = 0.04). CONCLUSION: These data suggest that HIIT may be advocated as a time-efficient strategy for eliciting comparable fitness benefits to traditional continuous exercise in inactive, overweight adults. However, in this population HIIT does not confer the same benefit to body fat levels as continuous exercise training.

A 12-week, randomised, controlled trial to examine the acceptability of the Korean diet and its effectiveness on weight and metabolic parameters in an Australian overweight and obese population.

BACKGROUND: South Korea has a significantly lower prevalence of overweight and obesity compared to Western countries. This may be due to differences between the traditional Korean diet (KD) and western diet (WD). OBJECTIVE: Our study investigated whether a Western population would accept a KD, compared to a WD, in a weight loss oriented lifestyle program. DESIGN: 70 overweight or obese participants were randomised to a 12-week weight loss program. All participants followed a standardised lifestyle intervention incorporating diet, exercise and behavioural modification techniques. KD participants were provided with a traditional Korean lunch and dinner (Monday to Saturday). WD participants were provided with a weekly grocery food voucher. Weight and metabolic parameters were measured. RESULTS: 60 participants completed the study (KD = 25; WD = 35). No significant difference was found for percentage weight loss (KD: -5.8 ± 4.7%; WD: -5.7 ± 4.1%; p = 0.93). On the 10-item Food Acceptability Questionnaire, there was a decline in acceptance for the KD group over the 12-week intervention. CONCLUSIONS: When incorporated into a lifestyle intervention a traditional KD resulted in similar weight loss to a WD, despite a significantly higher energy intake. Food acceptability scores significantly favoured the WD for some of the measures at week 12, and the most common staple Korean foods were reported highest amongst the food returns, suggesting that the KD was not as well accepted and less enjoyable on a range of measures. More variability in the menu and flexibility in portion sizes of the KD may improve its acceptance and could further optimise its weight loss potential for Westerners.