Is breakfast consumption detrimental, unnecessary, or an opportunity for health promotion? A review of cardiometabolic outcomes and functional food choices

Effects of low-carbohydrate diets, with and without caloric restriction, on inflammatory markers in adults: a systematic review and meta-analysis of randomized clinical trials

Low-carbohydrate diets (LCDs) have gained interest due to their favorable effects on health outcomes, such as inflammation. However, further research is needed to ascertain the overall effects of LCDs on inflammatory parameters, but at the same time considering weight loss and calorie intake. Thus, a systematic review and meta-analysis of randomized clinical trials was performed to investigate the effects of LCDs compared with low-fat diets (LFDs), with and without caloric restriction, on inflammatory markers in adults. PubMed, Scopus, and Web of Science were searched through March 2022 to select intervention studies addressing LCDs vs. LFDs, in which the following circulating inflammatory markers were used: C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and interleukin (IL-6). Analyses were conducted comparing LCDs vs. LFDs through weighted mean differences (WMD) or standardized mean differences (SMD) and 95% confidence intervals (95% CIs) using random effects models. The systematic review and meta-analysis included a total of 51 studies with a total sample of 4,164 adults, with or without other chronic diseases. Intervention durations ranged from 2-144 weeks. LCDs, compared with LFDs, significantly decreased body weight [WMD = -1.35%, p = 0.001], CRP [SMD = -0.1, p = 0.03], and IL-6 [SMD = -0.15, p = 0.09]. However, LCDs did not significantly decrease TNF-α [SMD = -0.02, p = 0.7] compared to LFDs. In conclusion, LCDs have a beneficial effect on markers of inflammation by decreasing CRP and IL-6; this effect has an association with weight loss. However, LCDs were not more effective than LFDs in decreasing TNF-α.

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.

Chrononutrition in cardiometabolic diseases: Current evidence and future perspectives

Chrononutrition is the field of nutritional science that investigates the relationship between food intake, timing of food intake, and their effects and influence on circadian rhythms and overall health. By aligning eating patterns with body's internal clock, optimisation of metabolic processes, improvements of various aspects of health can be achieved. Cardiovascular (CV) and metabolic diseases remain the leading cause of morbidity and mortality worldwide. Notably, in the US alone, approximately half of all cardiometabolic deaths are attributed to modifiable dietary factors, suggesting that dietary changes could result in dramatic increases in lifespan and its related quality of life. Social media have also a great impact on chrononutrition and their role cannot be neglected. The impact of social media on chrononutrition can be multifaceted: information dissemination, influence on eating habits, digital detox challenges, cultural influence and social jet lag. This special issue will provide novel insights and clarifications on chrononutrition, but also on additional controversial topics. The articles we selected should promote future preclinical and clinical studies to ultimately identify the most appropriate approaches to reduce the unacceptable high burden of CV and metabolic diseases.

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.

Effect of skipping breakfast on cardiovascular risk factors: a grade-assessed systematic review and meta-analysis of randomized controlled trials and prospective cohort studies

Skipping breakfast is one of the most prevalent irregular eating habits. Several pieces of evidence have reported the association between breakfast omission and a higher risk of cardiovascular diseases. Numerous publications have focused on the impact of skipping breakfast on various cardiovascular risk factors. Therefore, the current systematic review and meta-analysis aimed to assess this impact, especially with regard to anthropometric measurements, serum lipid profiles, blood pressure, and glycemic control indicators. A comprehensive search was performed in PubMed, Web of Science, Embase, Scopus, and the Cochrane Central Register of Controlled Trials up to 1 April 2023. A total of 11 eligible trials were identified to evaluate the combined effects of skipping breakfast. Final integrated results demonstrated that breakfast omission significantly decreased the body weight (mean difference = -0.66, 95% CI: -1.09 to -0.24, p = 0.002, I2 = 0.0) and increased the level of serum low-density lipoprotein cholesterol (LDL-C) (mean difference = 9.89, 95% CI: 5.14 to 14.63, p = 0.000, I2 = 17.3). Subgroup analysis also revealed potential factors that may affect the outcomes, for example, the physiological condition of participants, duration, gender, and type of breakfast. In conclusion, skipping breakfast may reduce body weight while increasing the level of serum LDL-C at the same time. In view of the limited trials, further studies are needed to expound the role of breakfast omission in cardiovascular diseases.

Intermittent fasting in the management of diabetes: a review of glycemic control and safety

Intermittent fasting (IF) regimens have emerged as a dietary tool to improve the glycemic profile, but a critical appraisal of clinical studies assessing the effects of IF regimens in patients with diabetes is needed. Thus, this review encompasses clinical studies examining the impact of different IF regimens on markers of glycemic control in patients with diabetes. Furthermore, clinical nuances relative to pharmacological treatment are also addressed, mainly insulin therapy, to discuss the risk of hypoglycemic events. Only a handful of clinical studies have investigated the effects of IF on patients with diabetes. Overall, IF regimens may elicit modest benefits on glycemic parameters in patients with diabetes, but their effects are not necessarily greater than those of control diets. Last, although IF regimens may be considered safe for patients receiving insulin therapy within interventional and observational research, markers of glycemic control must be constantly monitored in clinical practice to reduce the risk of hypoglycemia and its related complications.