Exercise training, dietary intervention, or combined interventions and their effects on lipid profiles in adults with overweight and obesity: A systematic review and meta-analysis of randomized clinical trials

Effects of intermittent fasting combined with exercise on serum leptin and adiponectin in adults with or without obesity: a systematic review and meta-analysis of randomized clinical trials

Context

Intermittent fasting (IF) and exercise training (Exe) have been evaluated in several studies for improving cardiometabolic biomarkers related to weight loss. However, further investigation is required to understand the potential effects on leptin and adiponectin concentrations. IF protocols have been shown to be efficient in improving adipokines, but further research is required to determine whether or not IF regimens combined with Exe are superior to Exe alone.

Objective

The aim of this study was to determine whether or not interventions combining IF plus Exe are more effective than Exe only for improving serum leptin and adiponectin in adults with and without obesity.

Data extraction

A systematic review and meta-analysis was performed by searching PubMed, Scopus, and Web of Science databases up to August 2023 for randomized clinical trials that determined the effects of IF plus Exe vs. Exe alone (control) on body weight, serum leptin, and serum adiponectin. Analyses were conducted for IF plus Exe vs. Exe alone to calculate weighted mean differences (WMD) and standardized mean differences (SMD).

Analysis

The current meta-analysis included 6 studies with a total sample of 153 participants, with intervention durations ranging from three days to 52 weeks. IF plus Exe elicited significantly larger decreases in leptin levels [SMD = -0.47, p = 0.03], which were accompanied by weight loss [WMD = -1.25 kg, p = 0.05], as compared with exercise-only interventions, but adiponectin did not differ between the two [SMD = 0.02, p = 0.9].

Conclusion

IF combined with Exe reduced leptin significantly, but did not change adiponectin levels, when compared to exercise only. Perhaps these reductions in leptin levels may have been associated with weight loss; however, due to the small number of included studies and the high heterogeneity in the weight loss outcomes, this result is uncertain.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023460735.

Combined versus independent effects of exercise training and intermittent fasting on body composition and cardiometabolic health in adults: a systematic review and meta-analysis

INTRODUCTION AND AIM

Exercise training (Ex) and intermittent fasting (IF) are effective for improving body composition and cardiometabolic health overweight and obese adults, but whether combining Ex and IF induces additive or synergistic effects is less well established. We therefore, performed a systematic review and meta-analysis to compare the combined versus independent effects of Ex and IF on body composition and cardiometabolic health in adults.

METHOD

An electronic search was conducted in three main online databases including PubMed, Web of Science, and Scopus, from inception to March 9, 2023 for studies involving Ex plus IF trials versus standalone Ex and/or IF interventions in adults. Interventions had a duration of ≥ 2 weeks. Standardized (SMD) or weighted mean differences (WMD) and 95% confidence intervals were calculated in order to compare effects on body weight, body mass index (BMI), body fat lean body mass (LBM), visceral fat, and waist circumference. For cardiometabolic health, outcomes included fasting glucose, insulin, total cholesterol (TC), low-density lipoprotein cholesterol (LDL), triglycerides (TG), high-density lipoprotein cholesterol (HDL), systolic (SBP) and diastolic (DBP) blood pressure, and VO2max/peak.

RESULTS

Ex plus IF decreased body weight [WMD: -3.03 kg (95% CI: -3.44 to -2.61), p = 0.001], BMI [WMD: -1.12 kg.m2 (95% CI: -1.28 to -0.95), p = 0.001], body fat [SMD: -0.72 (95% CI: -1.23 to -0.21), p = 0.005], visceral fat [SMD: -0.34 (95% CI: -0.63 to -0.05), p = 0.01], and waist circumference [WMD: -2.63 cm (95% CI: -4.16 to -1.11), p = 0.001] more than Ex alone. However, changes in body composition and cardiometabolic health markers were not significantly different for Ex plus IF when compared with IF alone, with the exception of VO2max/peak [SMD: 0.55 (95% CI: 0.14 to 0.97), p = 0.009].

CONCLUSION

We demonstrate that a combination of Ex and IF produces superior changes in body composition, but not in markers of cardiometabolic health when compared with Ex or IF alone. Ex plus IF could therefore be effective for weight and fat loss but has no additive or synergistic effects for other cardiometabolic health markers.

Effects of intermittent fasting combined with physical exercise on cardiometabolic outcomes: systematic review and meta-analysis of clinical studies

CONTEXT

Different intermittent fasting (IF) protocols have been proven to be efficient in improving cardiometabolic markers, but further research is needed to examine whether or not combining IF regimens plus physical exercise is superior to control diets (ie, nonfasting eating) plus physical exercise in this setting.

OBJECTIVE

The aim of this study was to determine whether or not combining IF plus exercise interventions is more favorable than a control diet plus exercise for improving cardiometabolic health outcomes.

DATA SOURCE

PubMed, Scopus, and Web of Science were comprehensively searched until April 2023.

DATA EXTRACTION

Electronic databases were searched for clinical trials that determined the effect of IF plus exercise vs a control diet plus exercise on body weight, lipid profile (high-density lipoprotein [HDL], low-density lipoprotein [LDL], triglycerides, and total cholesterol), and systolic and diastolic blood pressure (SBP and DBP, respectively). Analyses were conducted for IF plus exercise vs a nonfasting diet plus exercise to calculate weighted mean differences (WMDs).

DATA ANALYSIS

The meta-analysis included a total of 14 studies, with a total sample of 360 adults with or without obesity. The duration ranged from 4 to 52 weeks. IF plus exercise decreased body weight (WMD = -1.83 kg; P = 0.001), LDL (WMD = -5.35 mg/dL; P = 0.03), and SBP (WMD = -2.99 mm Hg; P = 0.003) significantly more than a control diet plus exercise. HDL (WMD = 1.57 mg/dL; P = 0.4) and total cholesterol (WMD = -2.24 mg/dL; P = 0.3) did not change significantly for IF plus exercise vs a control diet plus exercise, but there was a trend for reducing triglycerides (WMD = -13.13 mg/dL; P = 0.07) and DBP (WMD = 2.13 mm Hg; P = 0.05), which shows clinical magnitude.

CONCLUSION

IF plus exercise improved some cardiometabolic outcomes (body weight, blood pressure, and lipid profile) compared with a control diet plus exercise.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023423878.

Effects of Seven Weeks of Combined Physical Training on High-Density Lipoprotein Functionality in Overweight/Obese Subjects

Our study aimed to investigate the effects of exercise on HDL composition and functional properties in overweight/obese subjects. Eighteen overweight/obese subjects (nine F and nine M, BMI = 30.3 ± 3 kg/m2) attended supervised training for 7 weeks. The protocol included combined resistance and conditioning training four to five times each week. The activity of the antioxidant enzyme paraoxonase-1 (PON1) associated with HDL was evaluated in all subjects before and after the training intervention. Moreover, myeloperoxidase (MPO) levels and oxidative stress markers (ox-LDLs and total antioxidant capacity) were studied in the serums of the subjects. At the end of the intervention, the activity of PON1 was increased (p < 0.0001), and MPO levels and the MPO/PON1 ratio were decreased (p < 0.0001). In addition, a significant improvement in muscle strength and maximal oxygen uptake (VO2max) (p < 0.0001) and a significant reduction in total and visceral adipose tissue mass (p < 0.001) and waist circumference (p < 0.008), without any significant decrease in body weight, were observed. A significant correlation was established between serum MPO/PON ratios, HDL redox activity and ox-LDLs. In conclusion, our results demonstrate that exercise training, without modifications of dietary habits, improved HDL functionality in overweight/obese adults, without any significant reduction in BMI or modifications of glucose and lipid biochemical parameters.