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Time-restricted eating and exercise training improve HbA1c and body composition in women with overweight/obesity: A randomized controlled trial.
Haganes, KL, Silva, CP, Eyjólfsdóttir, SK, Steen, S, Grindberg, M, Lydersen, S, Hawley, JA, Moholdt, T
Cell metabolism. 2022;34(10):1457-1471.e4
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A healthy diet and regular physical activity are primary lifestyle strategies for the prevention and treatment of obesity and its associated conditions. However, poor adherence rates to these strategies limit their effectiveness. Time-restricted eating (TRE) is a popular dietary strategy that emphasises the timing of meals in alignment with diurnal circadian rhythms, permitting ad libitum energy intake during a restricted eating window (8–10 h between the first and last energy intake of the day). The aim of this study was to investigate the isolated and combined effects of TRE and high-intensity interval training (HIIT) on glycaemic control and cardiometabolic health outcomes in women with overweight/obesity. This study is a 7-week randomised controlled trial with four parallel groups: TRE (energy intake limited to a %10-h eating window every day), HIIT (three supervised treadmill exercise sessions per week), a combination (TREHIIT), and a control group (CON, no intervention). Participants (n=131) were randomly assigned to one of the four groups. . Results show that 7 weeks of TRE, HIIT, or a combination failed to improve glycaemic control in reproductive-aged women with overweight/obesity. However, the combination of TRE and HIIT significantly reduced glycated haemoglobin levels compared with CON and induced greater losses in body weight, fat mass, and visceral fat area compared with either intervention alone. Isolated TRE resulted in lower nocturnal glucose concentrations compared with CON. Authors conclude that combining TRE with HIIT can rapidly induce several health benefits and decrease metabolic disease risk in women with overweight/obesity. In fact, the high rates of compliance and adherence shown in their findings, highlight the potential of these diet-exercise (TRE and HIIT) protocols to be implemented in clinical practice for treatment and primary prevention of overweight/ obesity.
Abstract
Diet modification and exercise training are primary lifestyle strategies for obesity management, but poor adherence rates limit their effectiveness. Time-restricted eating (TRE) and high-intensity interval training (HIIT) improve cardiometabolic health in at-risk individuals, but whether these two interventions combined induce superior improvements in glycemic control than each individual intervention is not known. In this four-armed randomized controlled trial (ClinicalTrials.gov NCT04019860), we determined the isolated and combined effects of 7 weeks of TRE (≤10-h daily eating window, with ad libitum energy intake) and HIIT (three exercise sessions per week), compared with a non-intervention control group, on glycemic control and secondary cardiometabolic outcomes in 131 women (36.2 ± 6.2 years) with overweight/obesity. There were no statistically significant effects after isolated TRE, HIIT, or a combination (TREHIIT) on glucose area under the curve during an oral glucose tolerance test (the primary outcome) compared with the control group (TRE, -26.3 mmol/L; 95% confidence interval [CI], -82.3 to 29.7, p = 0.36; HIIT, -53.8 mmol/L; 95% CI, -109.2 to 1.6, p = 0.057; TREHIIT, -41.3 mmol/L; 95% CI, -96.4 to 13.8, p = 0.14). However, TREHIIT improved HbA1c and induced superior reductions in total and visceral fat mass compared with TRE and HIIT alone. High participant adherence rates suggest that TRE, HIIT, and a combination thereof may be realistic diet-exercise strategies for improving markers of metabolic health in women at risk of cardiometabolic disease.
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A Single Bout of Premeal Resistance Exercise Improves Postprandial Glucose Metabolism in Obese Men with Prediabetes.
Bittel, AJ, Bittel, DC, Mittendorfer, B, Patterson, BW, Okunade, AL, Abumrad, NA, Reeds, DN, Cade, WT
Medicine and science in sports and exercise. 2021;53(4):694-703
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Prediabetes is a metabolic condition defined by elevated fasting (impaired fasting glucose) and/or postprandial (impaired glucose tolerance) plasma glucose. The aim of this study was to determine the effects of a single bout of resistance exercise on postprandial glucose metabolism following a mixed meal in obese, sedentary men with prediabetes. This study is a randomised, cross-over study design which enrolled ten participants. Participants were aged 39-62 years, obese, and demonstrated insulin resistance with compensatory increases in beta cell function. Results show that a single bout of resistance exercise performed 4.5 hours before a mixed meal (as opposed to an oral glucose tolerance test) reduced total postprandial glucose appearance, increased insulin sensitivity, and reduced the glycaemic response to a mixed meal. However, it did not have effect on glucose oxidation in obese men with prediabetes. Improvements in insulin sensitivity were complemented by reduced postprandial insulin concentration. Authors conclude that further investigation is needed to elucidate how resistance exercise affects exogenous (meal) vs endogenous postprandial glucose metabolism, and if additional bouts of exercise (i.e. training) produce superior outcomes for this population.
Abstract
INTRODUCTION Prediabetes is a major risk factor for type 2 diabetes and cardiovascular diseases. Although resistance exercise (RE) is recommended for individuals with prediabetes, the effects of RE on postprandial glucose metabolism in this population are poorly understood. Therefore, the purpose of this study was to elucidate how RE affects postprandial glucose kinetics, insulin sensitivity, beta cell function, and glucose oxidation during the subsequent meal in sedentary men with obesity and prediabetes. METHODS We studied 10 sedentary men with obesity (body mass index, 33 ± 3 kg·m-2) and prediabetes by using a randomized, cross-over study design. After an overnight fast, participants completed either a single bout of whole-body RE (seven exercises, 3 sets of 10-12 repetitions at 80% one-repetition maximum each) or an equivalent period of rest. Participants subsequently completed a mixed meal test in conjunction with an intravenous [6,6-2H2]glucose infusion to determine basal and postprandial glucose rate of appearance (Ra) and disappearance (Rd) from plasma, insulin sensitivity, and the insulinogenic index (a measure of beta cell function). Skeletal muscle biopsies were obtained 90 min postmeal to evaluate pyruvate-supported and maximal mitochondrial respiration. Whole-body carbohydrate oxidation was assessed using indirect calorimetry. RESULTS RE significantly reduced the postprandial rise in glucose Ra and plasma glucose concentration. Postprandial insulin sensitivity was significantly greater after RE, whereas postprandial plasma insulin concentration was significantly reduced. RE had no effect on the insulinogenic index, postprandial pyruvate respiration, or carbohydrate oxidation. CONCLUSION/INTERPRETATION A single bout of RE has beneficial effects on postprandial glucose metabolism in men with obesity and prediabetes by increasing postprandial insulin sensitivity, reducing the postprandial rise in glucose Ra, and reducing postprandial plasma insulin concentration.
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Effects of A 12-Month Intensive Lifestyle Monitoring Program in Predominantly Overweight/Obese Arab Adults with Prediabetes.
Wani, K, Alfawaz, H, Alnaami, AM, Sabico, S, Khattak, MNK, Al-Attas, O, Alokail, MS, Alharbi, M, Chrousos, G, Kumar, S, et al
Nutrients. 2020;12(2)
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Key determinant factors associated with type 2 diabetes mellitus in the Arab world, aside from the genetic predisposition are obesity, rapid urbanization, and lack of physical activity. The aim of the study was to evaluate the effectiveness of a Diabetes Prevention Programme-based lifestyle modification program focused on overweight/obese Saudi adults with impaired fasting glucose. This study is a 12-month two-arm randomized controlled (1:1) lifestyle intervention. Participants were randomly assigned to receive either an intensive lifestyle modification program or general advice at the time of recruitment. Results showed that participants following the intensive lifestyle modification program had significant changes in body weight, body mass index and glycaemic indices post-intervention. Authors conclude that for Saudi adults with impaired fasting glucose, a self-monitoring-based lifestyle intervention may be a significant tool for weight loss and to reverse to normoglycemia [normal concentration of sugar in the blood].
Abstract
This 12-month, randomized, controlled lifestyle intervention study was aimed at assessing the effectiveness of a lifestyle intervention in terms of (1) the reduction of at least 5% of body weight compared to baseline and (2) the percentage of participants in which fasting blood glucose (FBG) normalizes (<5.6 mmol/L) post-intervention, in predominantly overweight/obese Saudi adults with impaired fasting glucose. A total of 300 Saudi adults with prediabetes at baseline (FBG 5.6-6.9 mmol/L) were enrolled to receive either general advice (GA) or a rigorous, self-monitored, lifestyle modification program (intervention group, IG) for 12 months, focused on food choices, physical activity, and weight loss. Anthropometric and biochemical estimations were analyzed at baseline, 6, and 12 months. At baseline, 136/150 in the GA group (90.7%) and 127/150 in the IG group (84.7%) were either overweight or obese. A total of 14% (n = 21) of the subjects in the IG arm discontinued, compared to 8% (n = 12) in the GA arm. Data from completers (92% (n = 138) and 86% (n= 129) participants in GA and IG arms, respectively) were considered for the final analysis. Post-intervention, 37.2% (n = 48) of participants in the IG group had ≥5% weight reduction, as compared to 12.3% (n = 17) in the GA group (p < 0.01). Similarly, the percentage of participants who normalized their FBG post-intervention was 46.5% (n = 60) in the IG group compared to 21.7% (n = 30) in the GA group (p < 0.01). A 12-month Diabetes Prevention Program (DPP)-styled intensive lifestyle program translated effectively in decreasing weight and improving fasting glucose compared to the GA group in predominantly overweight/obese Saudi adults with prediabetes, suggesting that in the case of guided intervention programs, people are willing to participate and possibly change a sedentary lifestyle.