Carbohydrate Restriction with or without Exercise Training Improves Blood Pressure and Insulin Sensitivity in Overweight Women

Effect of high-intensity interval training compared to moderate-intensity continuous training on body composition and insulin sensitivity in overweight and obese adults: A systematic review and meta-analysis

Objective

To compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on adults with overweight and obesity. Outcomes, including changes in insulin sensitivity, weight, body mass index (BMI), waist circumference, and body fat, were analyzed.

Methods

A systematic literature review was conducted. This review is registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42021281899. Clinical trials involving individuals who are overweight and obese and comparing HIIT with MICT effects on insulin sensitivity, weight, BMI, body fat percentage, and waist circumference were included. PubMed, Web of Science, Embase, and Scopus databases were searched using controlled vocabulary and free-text terms related to HIIT, obesity, and overweight. The search included studies published until September 2022. The Rob2 tool was used to assess the risk of bias. The results were presented through meta-analyses that provided summary estimators and confidence intervals. Subgroup analyses were conducted to assess the effect of the risk of bias on the outcomes. This research did not receive any specific funding.

Results

Of the 2534 articles, 30 met the eligibility criteria. The intervention duration ranged from 4 to 16 weeks. The observed effects for each outcome were as follows: insulin sensitivity (p = 0.02), weight (p = 0.58), BMI (p = 0.53), waist circumference (p = 0.87), body fat percentage (p = 0.07), body fat mass in kilograms (p = 0.39). The level of evidence obtained was moderate except for waist circumference, which was rated as low. Limitations included heterogeneity in training protocols, measurements, and study duration. Additionally, a risk of bias was identified in these studies.

Conclusion

HIIT and MICT did not significantly differ in their effects on weight, BMI, waist circumference, or body fat mass in adults with overweight and obesity. However, a moderate beneficial effect of HIIT was observed on insulin sensitivity. Therefore, further evidence is required to confirm these findings.

The impact of exercise and dietary interventions on circulating leptin and adiponectin in individuals who are overweight and those with obesity: A systematic review and meta-analysis

The effects of exercise training (Ex), dietary interventions (DIs), and a combination of Ex and DI (Ex + DI) on leptin and adiponectin have been established. However, less is known regarding the comparisons of Ex with DI and of Ex + DI with either Ex or DI alone. The aim of the present meta-analysis is to compare the effects of Ex with those of DI and those of Ex + DI with those of either Ex or DI alone on circulating leptin and adiponectin in individuals who are overweight and those with obesity. PubMed, Web of Science, and MEDLINE were searched to identify original articles, published through June 2022, that compared the effects of Ex with those of DI and/or the effects of Ex + DI with those of Ex and/or DI on leptin and adiponectin in individuals with BMIs (in kg/m²) of ≥25 and aged 7-70 y. Standardized mean differences (SMDs), weighted mean differences, and 95% CIs were calculated using random-effect models for outcomes. Forty-seven studies, comprising 3872 participants who were overweight and those with obesity, were included in the current meta-analysis. DI reduced the concentration of leptin (SMD: -0.30; P = 0.001) and increased the concentration of adiponectin (SMD: 0.23; P = 0.001) compared with Ex, as did Ex + DI (leptin: SMD: -0.34; P = 0.001; adiponectin: SMD: 0.37; P = 0.004) compared with Ex alone. However, Ex + DI did not affect the concentration of adiponectin (SMD: 0.10; P = 0.11) and led to inconsistent and nonsignificant changes in the concentration of leptin (SMD: -0.13; P = 0.06) compared with DI alone. Subgroup analyses showed that age, BMI, duration of intervention, type of supervision, quality of the study, and magnitude of energy restriction are sources of heterogeneity. Our results suggest that Ex alone was not as effective as DI or Ex + DI for decreasing leptin and increasing adiponectin in individuals with overweight and obesity. However, Ex + DI was not more effective than DI alone, suggesting that diet plays a critical role in beneficially altering the concentrations of leptin and adiponectin. This review was registered at PROSPERO as CRD42021283532.

Combined Physical Exercise and Diet: Regulation of Gut Microbiota to Prevent and Treat of Metabolic Disease: A Review

BACKGROUND

Unhealthy diet and sedentary lifestyle have contributed to the rising incidence of metabolic diseases, which is also accompanied by the shifts of gut microbiota architecture. The gut microbiota is a complicated and volatile ecosystem and can be regulated by diet and physical exercise. Extensive research suggests that diet alongside physical exercise interventions exert beneficial effects on metabolic diseases by regulating gut microbiota, involving in the changes of the energy metabolism, immune regulation, and the microbial-derived metabolites.

OBJECTIVE

In this review, we present the latest evidence in the modulating role of diet and physical exercise in the gut microbiota and its relevance to metabolic diseases. We also summarize the research from animal and human studies on improving metabolic diseases through diet-plus-exercise interventions, and new targeted therapies that might provide a better understanding of the potential mechanisms.

METHODS

A systematic and comprehensive literature search was performed in PubMed/Medline and Web of Science in October 2022. The key terms used in the searches included "combined physical exercise and diet", "physical exercise, diet and gut microbiota", "physical exercise, diet and metabolic diseases" and "physical exercise, diet, gut microbiota and metabolic diseases".

CONCLUSIONS

Combined physical exercise and diet offer a more efficient approach for preventing metabolic diseases via the modification of gut microbiota, abating the burden related to longevity.

Effect of a Low-Carbohydrate Diet With or Without Exercise on Anxiety and Eating Behavior and Associated Changes in Cardiometabolic Health in Overweight Young Women

Background

The effectiveness of low-carbohydrate diets (LCDs) on weight loss and exercise for improving cardiometabolic fitness have been well documented in the literature, but the effects of LCDs and whether adding exercise to a LCD regime could additionally benefit mental health (e. g., by lowering the level of anxiety) and associated changes in eating behavior are less clear in overweight and obese populations. Therefore, this study aimed to investigate the effects of a 4-week LCD with or without exercise on anxiety and eating behavior, and to explore the associations between changes in the psychological state and physiological parameters (i.e., body composition, aerobic fitness, blood pressure, lipid profile, and metabolic hormones).

Methods

Seventy-four overweight Chinese women [age: 20.8 ± 3.0 years, body mass index (BMI): 25.3 ± 3.3 kg·m⁻²] completed the 4-week randomized controlled trial, which included a LCD group (i.e., ~50 g daily carbohydrate intake) with exercise training 5 days/week (LC-EXE, n = 26), a LCD group without exercise training (LC-CON, n = 25) and a control group that did not modify their habitual diets and physical activity (CON, n = 23). Levels of anxiety, eating behavior scores and physiological parameters (i.e., body weight, V̇O_2peak, blood pressure, fasting glucose, blood lipids, and serum metabolic hormones including insulin, C-peptide, leptin, and ghrelin) were measured before and after the intervention.

Results

There were significant reductions in anxiety levels in the LC-EXE compared with the LC-CON group, while no statistical changes were found in eating behaviors in any conditions after the 4-week intervention. Significant reduction in weight (~3.0 kg or 4%, p < 0.01) and decreases in insulin (~30% p < 0.01), C-peptide (~20% p < 0.01), and leptin (~40%, p < 0.01) were found in both LC-CON and LC-EXE groups, but adding exercise to a LCD regime generated no additional effects. There were significant improvements in V̇O_2peak (~15% p < 0.01) and anxiety (~25% p < 0.01) in the LC-EXE compared with the LC-CON group, while no statistical differences were found between CON and LC-CON treatments. Further analysis revealed a negative association (r = −0.32, p < 0.01) between changes in levels of anxiety and changes in V̇O_2peak in all participates, no other correlations were found between changes in psychological and physiological parameters.

Conclusion

Although the combination of a LCD and exercise may not induce additional reductions in body weight in overweight young females, exercise could be a useful add-on treatment along with a LCD to improve cardiometabolic health and lower anxiety levels.

Very Low-Carbohydrate High-Fat Diet Improves Risk Markers for Cardiometabolic Health More Than Exercise in Men and Women With Overfat Constitution: Secondary Analysis of a Randomized Controlled Clinical Trial

Purpose

This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12-weeks on cardiometabolic risk factors in individuals with overfat constitution.

Methods

Ninety-one participants out of 109 completed the study. The participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Fasting plasma samples were collected before the intervention and after 4 and 12 weeks. The analyzed outcomes included complete blood count, glucose, insulin, glycated hemoglobin, triglycerides (TG), cholesterol, high- and low-density lipoprotein (HDL-C and LDL-C), lipoprotein(a), adiponectin (Adpn), leptin (Lep), tumor necrosis factor α (TNF-α), other interleukins (hs-IL-6, IL-1β, and IL-10), and IL-1RA. The homeostasis model assessment of insulin resistance (HOMA-IR), Adpn/Lep ratio, TG/HDL-C ratio, and TyG index were calculated and analyzed. Blood pressure was measured before the intervention, after 4, 8, and 12 weeks (ClinicalTrials.gov: NCT03934476).

Results

Absolute changes in HOMA-IR, Adpn/Lep ratio, LDL-C, and diastolic blood pressure after 12 weeks differed by study groups (p < 0.05). The most pronounced changes were revealed in the VLCHF (ΔM [95% CI]; HOMA-IR: −0.75 [−1.13; −0.55]; Adpn/Lep: 9.34 [6.33; 37.39]; LDL-C: 0.06 [−0.12; 0.50] mmol/l) and VLCHF+HIIT (HOMA-IR: −0.44 [−1.14; 0.12]; Adpn/Lep: 4.26 [2.24; 13.16]; LDL-C: 0.25 [−0.04; 0.50] mmol/l) groups.

Conclusions

A 12-week VLCHF diet intervention in individuals with overfat constitution is effective for favorable changes in HOMA-IR (compared to HIIT), Adpn/Lep ratio, and diastolic blood pressure. HIIT, or HIIT combined with the VLCHF diet, had no additional benefits for the analyzed variables. No adverse side effects were observed.

Effects of Low-Carbohydrate Diet and Exercise Training on Gut Microbiota

Objective

This study was aimed to evaluate the effects of low-carbohydrate diet (LC) and incorporated high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) on gut microbiota, and the associations between changes in gut microbiota and cardiometabolic health-related profiles.

Methods

Fifty overweight/obese Chinese females (age 22.2 ± 3.3 years, body mass index 25.1 ± 3.1 kg/m–2) were randomized to the groups of LC, LC and HIIT (LC-HIIT, 10 repetitions of 6-s sprints and 9-s rest), and LC and MICT group (LC-MICT, cycling at 50–60% V̇O2peak for 30 min). The LC-HIIT and LC-MICT experienced 20 training sessions over 4 weeks.

Results

The 4-week LC intervention with/without additional training failed to change the Shannon, Chao 1, and Simpson indexes (p &gt; 0.05), LC increased Phascolarctobacterium genus, and LC-HIIT reduced Bifidobacterium genus after intervention (p &lt; 0.05). Groups with extra exercise training increased short-chain fatty acid-producing Blautia genus (p &lt; 0.05) and reduced type 2 diabetes-related genus Alistipes (p &lt; 0.05) compared to LC. Sutterella (r = −0.335) and Enterobacter (r = 0.334) were associated with changes in body composition (p &lt; 0.05). Changes in Ruminococcus, Eubacterium, and Roseburia genera were positively associated with blood pressure (BP) changes (r = 0.392–0.445, p &lt; 0.05), whereas the changes in Bacteroides, Faecalibacterium, and Parabacteroides genera were negatively associated with BP changes (r = −0.567 to −0.362, p &lt; 0.05).

Conclusion

LC intervention did not change the α-diversity and overall structure of gut microbiota. Combining LC with exercise training may have additional benefits on gut physiology. Specific microbial genera were associated with LC- and exercise-induced regulation of cardiometabolic health.

Effects of a Low-Carbohydrate High-Fat Diet Combined with High-Intensity Interval Training on Body Composition and Maximal Oxygen Uptake: A Systematic Review and Meta-Analysis

The low-carbohydrate high-fat (LCHF) diet has recently been subject to attention on account of its reported influences on body composition and physical performance. However, the combined effect of LCHF with high-intensity interval training (HIIT) is unclear. A systematic review and meta-analysis were conducted to explore the effect of the LCHF diet combined with HIIT on human body composition (i.e., body weight (BM), body mass index (BMI), fat mass (FM), body fat percentage (BFP), fat-free mass (FFM)) and maximal oxygen uptake (VO_2max). Online libraries (PubMed, Web of Science, EMBASE, Cochrane Library, EBSCO, CNKI, Wan Fang) were used to search initial studies until July 2021, from which 10 out of 2440 studies were included. WMD served as the effect size with a confidence interval value of 95%. The results of meta-analysis showed a significant reduction in BM (WMD = −5.299; 95% CI: −7.223, −3.376, p = 0.000), BMI (WMD = −1.150; 95% CI: −2.225, −0.075, p = 0.036), BFP (WMD = −2.787; 95% CI: −4.738, −0.835, p = 0.005) and a significant increase in VO_2max (WMD = 3.311; 95% CI: 1.705, 4.918, p = 0.000), while FM (WMD = −2.221; 95% CI: −4.582, 0.139, p = 0.065) and FFM (WMD = 0.487; 95% CI: −3.512, 4.469, p = 0.814) remained unchanged. In conclusion, the LCHF diet combined with HIIT can reduce weight and fat effectively. This combination is sufficient to prevent muscle mass loss during LCHF, and further enhance VO_2max. Further research might be required to clarify the effect of other types of exercise on body composition and physical performance during LCHF.