Impact of intermittent fasting on the lipid profile: Assessment associated with diet and weight loss

Intermittent Fasting and Metabolic Health

Given the ongoing strain that the obesity epidemic has placed on public health outcomes, new and effective approaches to weight control are needed. One approach to improving weight and metabolic outcomes is intermittent fasting, which consists of multiple different timing schedules for temporary food avoidance, including alternate-day fasting, other similar full-day fasting patterns, and time-restricted feeding (where the day’s food is consumed over a 6-h period, allowing for 18 h of fasting). These feeding schedules have favorable metabolic effects by intermittently inducing the metabolism of fatty acids to ketones. The regimens overall lead to a decrease in weight and have been linked to improvements in dyslipidemia and blood pressure. While more research is needed on longer-term outcomes and this approach should be avoided in particular health conditions, intermittent fasting should be considered as an option for individuals who have a pattern of unhealthy weight gain using standard eating patterns.

Walking Football During Ramadan Fasting for Cardiometabolic and Psychological Health Benefits to the Physically Challenged and Aged Populations

Concurrent exercise and intermittent fasting regimens for long periods have been shown to enhance cardiometabolic health in healthy individuals. As exercise and fasting confer health benefits independently, we propose that Muslims who are fasting, especially those experiencing health and clinical challenges, continually engage in physical activity during the Ramadan month. In this opinion piece, we recommend walking football (WF) as the exercise of choice among Muslims who are fasting. WF can be played by any individual regardless of the level of fitness, skills, and age. WF has been shown to elicit cardiovascular and metabolic stress responses, which are suitable for populations with low fitness levels. Most importantly, WF has the inherent characteristics of being a fun team activity requiring social interactions among participants and, hence, likely to encourage long-term consistent and sustainable participation.

Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis

The question of whether or not intermittent fasting diets improve the clinical indicators of glycolipid metabolism remains unclear. This study systematically reviewed the relevant clinical trials to evaluate the effects of intermittent fasting diet on glucose and lipid metabolism and insulin sensitivity in patients with metabolic syndrome. To evaluate the effect of intermittent fasting diet intervention on patients with disorders of glucose and lipid metabolism, random-effect or fixed-effect meta-analysis models were used to calculate the average difference before and after intermittent fasting diet intervention and the corresponding 95% confidence intervals (CIs). After intermittent fasting diet intervention, in terms of glucose metabolism, fasting blood glucose reduced by 0.15 mmol/L (95% CI: -0.23; -0.06), glycosylated hemoglobin reduced by 0.08 (95% CIs: -0.25; -0.10), insulin plasma levels reduced by 13.25 uUI (95% CIs: -16.69; -9.82), and HOMA-IR decreased by 0.31 on an average (95% CIs: -0.44; -0.19). In addition, BMI decreased by 0.8 kg/m² (95% CIs: -1.32; -0.28), body weight reduced by 1.87 kg (95% CIs: -2.67; -1.07), and the waist circumference decreased by 2.08 cm (95% CIs: -3.06; -1.10). Analysis of lipid metabolism showed that intermittent fasting diet intervention effectively reduced the total cholesterol level by 0.32 mmol/L (95% CIs: -0.60; -0.05), low-density lipoprotein level by 0.22 mmol/L (95% CIs: -0.37; -0.07), and triglyceride level by 0.04 mmol/L (95% CIs: -0.15; -0.07). Intermittent fasting diets have certain therapeutic effects on blood glucose and lipids in patients with metabolic syndrome and significantly improve insulin resistance. It may be considered as an auxiliary treatment to prevent the occurrence and development of chronic diseases.

Feeding frequency affects glucose and lipid metabolism through SIRT1/AMPK pathway in growing pigs with the same amount of daily feed

Eating patterns are associated with obesity and metabolic health. However, the regulating mechanism of different eating patterns on body metabolism are not fully cleare. In this study, a pig model was used to evaluate the effects of feeding frequency on glucose and lipid metabolism and reveal its regulating mechanism. Twenty-four growing barrows were randomly allocated to 1-meal (M1), 3-meal (M3), or 5-meal (M5) per day groups with the same amount of daily feed. GSEA was conducted on the liver to investigate the pathways of different feeding frequencies on the metabolism. The serum glucose, NEFA, VLDL-C levels were higher for M1 group than for M3 and M5 groups, however, the hepatic TRIG level was lower. Liver transcriptome showed that glycolysis/gluconeogenesis and fatty acid metabolism pathways were suppressed with the increase of feeding frequency. The increase of gluconeogenic substrates (glycerol and lactate) and enzymes (PEPCK1 and G6Pase) in liver indicated that hepatic gluconeogenesis was enhanced in the M1 group. AMPK/PPARα signaling associated genes were positively correlated with NEFA and β-HB levels in M1 group, which promoted fatty acid oxidation and ketogenesis in liver. Moreover, compared with M3 and M5 groups, the higher NAD⁺/NADH ratio in the liver of M1 group activated SIRT1, which stimulated the AMPK signaling associated pathways by up-regulating the LKB1 gene. These findings provide evidence for the regulating roles of feeding frequency on glucose and lipid metabolism through SIRT1/AMPK pathway, which greatly contributes to the regulation of energy metabolism through daily eating patterns in animals.

Does four-week consecutive, dawn-to-sunset intermittent fasting during Ramadan affect cardiometabolic risk factors in healthy adults? A systematic review, meta-analysis, and meta-regression

AIMS

This study aimed to evaluate the effects of Ramadan diurnal intermittent fasting (RDIF; 29-30 days) on cardiometabolic risk factors (CMRF) in healthy adults, and examine the effect of various cofactors on the outcomes using sub-group meta-regression.

DATA SYNTHESIS

We conducted a systematic review and meta-analysis to measure the effect sizes of changes in CMRF in healthy adult Muslims observing RDIF. Ten scientific databases (EBSCOhost, CINAHL, Cochrane, EMBASE, PubMed/MEDLINE, Scopus, Google Scholar, ProQuest Medical, ScienceDirect, and Web of Science) were searched from the date of inception (1950) to the end of November 2020. The CMRF searched and analyzed were total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), diastolic blood pressure (DBP), and heart rate (HR). We identified 91 studies (4431 adults aged 18-85 years) conducted between 1982 and 2020 in 23 countries distributed over four continents. RDIF-induced effect sizes for CMRF were: TC (no. of studies K = 77, number of subjects N = 3705, Hedge's g = -0.092, 95% confidence interval (CI): -0.168, 0.016); TG (K = 74, N = 3591, Hedge's g = -0.127, 95% CI: -0.203, 0.051); HDL-C (K = 68, N = 3528, Hedge's g = 0.138, 95% CI: 0.051, 0.224); LDL-C (K = 65, N = 3354, Hedge's g = -0.115, 95% CI: -0.197, -0.034); VLDL-C (K = 13, N = 648, Hedge's g = -0.252, 95% CI: -0.431, 0.073), DBP (K = 32, N = 1716, Hedge's g = -0.255, 95% CI: -0.363, 0.147), and HR (K = 12, N = 674, Hedge's g = -0.082, 95% CI: -0.300, 0.136). Meta-regression revealed that the age of fasting people was a significant moderator of changes in both HDL-C (P = 0.02) and VLDL-C (P = 0.01). Male sex was the only significant moderator of changes in LDL-C (P = 0.055). Fasting time duration was the only significant moderator of HDL-C (P = 0.001) at the end of Ramadan.

CONCLUSIONS

RDIF positively impacts CMRF, which may confer short-term transient protection against cardiovascular disease among healthy people.

A comparison of dietary quality and nutritional adequacy of popular energy-restricted diets against the Australian Guide to Healthy Eating and the Mediterranean Diet

There is limited information regarding the nutrition profile and diet quality of meal plans from currently popular weight loss (WL) diets in Australia. This includes the energy content (kilojoules), the macronutrient distribution and the micronutrient composition. Further, these diets have not been compared with current government guidelines and healthy eating principles (HEP) for nutritional adequacy. Popular diets were identified through grey literature, trending searches and relative popularity in Australia. Meal plans for each diet were analysed using Foodworks Dietary Software to determine food group intake, micronutrient and macronutrient distribution. The results indicated that all popular diets assessed deviated from government recommended HEP such as the Australian Guide to Healthy Eating and the Mediterranean diet. In most cases, both popular diets and the HEP had low intakes of multiple food groups, low intakes of essential micronutrients and a distorted macronutrient distribution. Popular diets may not provide adequate nutrition to meet needs, particularly in the long term and potentially resulting in micronutrient deficiency. When energy restricting for WL, meal plans should be highly individualised in conjunction with a qualified nutrition professional to ensure adequate dietary intake.

The influence of fasting and energy-restricted diets on leptin and adiponectin levels in humans: A systematic review and meta-analysis

BACKGROUND & AIMS

Fasting and energy-restricted diets have been evaluated in several studies as a means of improving cardiometabolic biomarkers related to body fat loss. However, further investigation is required to understand potential alterations of leptin and adiponectin concentrations. Thus, we performed a systematic review and meta-analysis to derive a more precise estimate of the influence of fasting and energy-restricted diets on leptin and adiponectin levels in humans, as well as to detect potential sources of heterogeneity in the available literature.

METHODS

A comprehensive systematic search was performed in Web of Science, PubMed/MEDLINE, Cochrane, SCOPUS and Embase from inception until June 2019. All clinical trials investigating the effects of fasting and energy-restricted diets on leptin and adiponectin in adults were included.

RESULTS

Twelve studies containing 17 arms and a total of 495 individuals (intervention = 249, control = 246) reported changes in serum leptin concentrations, and 10 studies containing 12 arms with a total of 438 individuals (intervention = 222, control = 216) reported changes in serum adiponectin concentrations. The combined effect sizes suggested a significant effect of fasting and energy-restricted diets on leptin concentrations (WMD: -3.690 ng/ml, 95% CI: -5.190, -2.190, p ≤ 0.001; I2 = 84.9%). However, no significant effect of fasting and energy-restricted diets on adiponectin concentrations was found (WMD: -159.520 ng/ml, 95% CI: -689.491, 370.451, p = 0.555; I2 = 74.2%). Stratified analyses showed that energy-restricted regimens significantly increased adiponectin (WMD: 554.129 ng/ml, 95% CI: 150.295, 957.964; I2 = 0.0%). In addition, subsequent subgroup analyses revealed that energy restriction, to ≤50% normal required daily energy intake, resulted in significantly reduced concentrations of leptin (WMD: -4.199 ng/ml, 95% CI: -7.279, -1.118; I2 = 83.9%) and significantly increased concentrations of adiponectin (WMD: 524.04 ng/ml, 95% CI: 115.618, 932.469: I2 = 0.0%).

CONCLUSION

Fasting and energy-restricted diets elicit significant reductions in serum leptin concentrations. Increases in adiponectin may also be observed when energy intake is ≤50% of normal requirements, although limited data preclude definitive conclusions on this point.

The association of skipping breakfast with cancer-related and all-cause mortality in a national cohort of United States adults

PURPOSE

Many lifestyle and dietary factors have been recognized as risk factors for cancer morbidity and mortality. However, investigations of the association of the frequency of breakfast consumption and cancer are limited. This study aimed to examine the association of skipping breakfast with all-cause and cancer-related mortality in a national cohort of United States men and women.

METHODS

Data were from 7,007 adults aged ≥ 40 years who participated in the third National Health and Nutrition Examination Survey (1988-1994) and had follow-up information on mortality up until 31 December 2015. Cox proportional hazards regression models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

The mean age of participants was 55.4 years, with 54.4% and 79% being women and non-Hispanic whites, respectively. Approximately, 16% of participants rarely consumed breakfast, 23.0% consumed breakfast some days, and 61% consumed breakfast every day. During a median follow-up of 22.2 years, 3,573 deaths occurred with 795 being related to cancer. In models adjusting for sociodemographic factors, smoking, physical activity, body mass index, hypertension, diabetes, cholesterol levels, total energy intake and diet quality, persons who rarely consumed breakfast had a higher risk of cancer-related mortality (HR = 1.52; CI:1.06-2.18) and all-cause (HR = 1.69; CI: 1.42-2.02) compared to those who took breakfast every day.

CONCLUSION

In this nationally representative sample, skipping breakfast was associated with elevated risks for all-cause and cancer-related mortality. This study provides evidence for the benefits of regular breakfast consumption in reducing the risk of all-cause and cancer mortality.

Impact of Intermittent Fasting on Lipid Profile-A Quasi-Randomized Clinical Trial

Background: Sub-optimal HDL is a prognostic marker of cardiovascular disease. South Asia has a high prevalence of sub-optimal HDL compared to other parts of the world. Intermittent fasting (IF) is a type of energy restriction which may improve serum HDL and other lipids thereby reducing the risk of cardiovascular diseases.

Objective: The aim of the study was to evaluate the effect of IF on lipid profile and HDL-cholesterol in a sample of South Asian adults.

Methods: A 6-week quasi-experimental (non-randomized) clinical trial was conducted on participants with low HDL (< 40 mg/dl for men and < 50 mg/dl for women). Participants of the control group were recommended not to change their diet. The intervention group was recommended to fast for ~12 h during day time, three times per week for 6 weeks. Pulse rate, blood pressure, body weight, waist circumference, serum lipid profile, and blood glucose levels were measured at baseline and after 6 weeks.

Result: A total of 40 participants were enrolled in the study (N = 20 in each group), while 35 (20 control and 15 intervention) completed the trial and were included in data analysis of the study. Body measurements, including body weight, BMI and waist circumference, showed significant interaction effects (p's < 0.001), indicating that there were larger reductions in the IF group than in the control group. Significant interaction effects were also observed for total (p = 0.033), HDL (p = 0.0001), and LDL cholesterol (p = 0.010) with larger improvements in the IF group.

Conclusion: This study suggests that intermittent fasting may protect cardiovascular health by improving the lipid profile and raising the sub-optimal HDL. Intermittent fasting may be adopted as a lifestyle intervention for the prevention, management and treatment of cardiovascular disorders.

Clinical Trial Registration: NCT03805776, registered on January 16, 2019, https://clinicaltrials.gov/ct2/show/NCT03805776

Intermittent fasting for the prevention of cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death worldwide. Lifestyle changes are at the forefront of preventing the disease. This includes advice such as increasing physical activity and having a healthy balanced diet to reduce risk factors. Intermittent fasting (IF) is a popular dietary plan involving restricting caloric intake to certain days in the week such as alternate day fasting and periodic fasting, and restricting intake to a number of hours in a given day, otherwise known as time-restricted feeding. IF is being researched for its benefits and many randomised controlled trials have looked at its benefits in preventing CVD.

OBJECTIVES

To determine the role of IF in preventing and reducing the risk of CVD in people with or without prior documented CVD.

SEARCH METHODS

We conducted our search on 12 December 2019; we searched CENTRAL, MEDLINE and Embase. We also searched three trials registers and searched the reference lists of included papers. Systematic reviews were also viewed for additional studies. There was no language restriction applied.

SELECTION CRITERIA

We included randomised controlled trials comparing IF to ad libitum feeding (eating at any time with no specific caloric restriction) or continuous energy restriction (CER). Participants had to be over the age of 18 and included those with and without cardiometabolic risk factors. Intermittent fasting was categorised into alternate-day fasting, modified alternate-day fasting, periodic fasting and time-restricted feeding.

DATA COLLECTION AND ANALYSIS

Five review authors independently selected studies for inclusion and extraction. Primary outcomes included all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure. Secondary outcomes include the absolute change in body weight, and glucose. Furthermore, side effects such as headaches and changes to the quality of life were also noted. For continuous data, pooled mean differences (MD) (with 95% confidence intervals (CIs)) were calculated. We contacted trial authors to obtain missing data. We used GRADE to assess the certainty of the evidence.  MAIN RESULTS: Our search yielded 39,165 records after the removal of duplicates. From this, 26 studies met our criteria, and 18 were included in the pooled analysis. The 18 studies included 1125 participants and observed outcomes ranging from four weeks to six months. No studies included data on all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure at any point during follow-up. Of quantitatively analysed data, seven studies compared IF with ab libitum feeding, eight studies compared IF with CER, and three studies compared IF with both ad libitum feeding and CER. Outcomes were reported at short term (≤ 3 months) and medium term (> 3 months to 12 months) follow-up. Body weight was reduced with IF compared to ad libitum feeding in the short term (MD -2.88 kg, 95% CI -3.96 to -1.80; 224 participants; 7 studies; low-certainty evidence). We are uncertain of the effect of IF when compared to CER in the short term (MD -0.88 kg, 95% CI -1.76 to 0.00; 719 participants; 10 studies; very low-certainty evidence) and there may be no effect in the medium term (MD -0.56 kg, 95% CI -1.68 to 0.56; 279 participants; 4 studies; low-certainty evidence). We are uncertain about the effect of IF on glucose when compared to ad libitum feeding in the short term (MD -0.03 mmol/L, 95% CI -0.26 to 0.19; 95 participants; 3 studies; very-low-certainty of evidence) and when compared to CER  in the short term: MD -0.02 mmol/L, 95% CI -0.16 to 0.12; 582 participants; 9 studies; very low-certainty; medium term: MD 0.01, 95% CI -0.10 to 0.11; 279 participants; 4 studies; low-certainty evidence). The changes in body weight and glucose were not deemed to be clinically significant. Four studies reported data on side effects, with some participants complaining of mild headaches. One study reported on the quality of life using the RAND SF-36 score. There was a modest increase in the physical component summary score.

AUTHORS' CONCLUSIONS

Intermittent fasting was seen to be superior to ad libitum feeding in reducing weight. However, this was not clinically significant. There was no significant clinical difference between IF and CER in improving cardiometabolic risk factors to reduce the risk of CVD. Further research is needed to understand the safety and risk-benefit analysis of IF in specific patient groups (e.g. patients with diabetes or eating disorders) as well as the effect on longer-term outcomes such as all-cause mortality and myocardial infarction.

Association between Breakfast Skipping and Body Weight-A Systematic Review and Meta-Analysis of Observational Longitudinal Studies

Globally, increasing rates of obesity are one of the most important health issues. The association between breakfast skipping and body weight is contradictory between cross-sectional and interventional studies. This systematic review and meta-analysis aims to summarize this association based on observational longitudinal studies. We included prospective studies on breakfast skipping and overweight/obesity or weight change in adults. The literature was searched until September 2020 in PubMed and Web of Science. Summary risk ratios (RRs) or β coefficients with a 95% confidence interval (CI), respectively, were estimated in pairwise meta-analyses by applying a random-effects model. In total, nine studies were included in the systematic review and three of them were included in the meta-analyses. The meta-analyses indicated an 11% increased RR for overweight/obesity when breakfast was skipped on ≥3 days per week compared to ≤2 days per week (95% CI: 1.04, 1.19, n = two studies). The meta-analysis on body mass index (BMI) change displayed no difference between breakfast skipping and eating (β = −0.02; 95% CI: −0.05, 0.01; n = two studies). This study provides minimal evidence that breakfast skipping might lead to weight gain and the onset of overweight and obesity.

A prospective controlled study on Ramadan fasting in the healthy young males in summer in Germany: effect on cytokines

SHORT COMMUNICATION

During the Ramadan fasting (RF) month, participants restrict some activities during day time, particularly consumption of food and beverages. In Germany, Muslims fast about 18-19 h a day when Ramadan falls in the summer. This longer period of restriction could lead to the changes of the body physiology, anthropometric parameters and biological mediators.

OBJECTIVES

This study aimed to determine the effect of Ramadan fasting on cytokines (Interleukin (IL)-1β. IL-6, IL-8, IL-10, IL-12, tumor necrosis factor (TNF)-α) during RF in Germany. Correlations of cytokines with anthropometric parameters were also determined.

METHODS

Fifty healthy adult males were recruited and divided into two equal groups: fasting group (FG) and non-fasting group (NFG). FG was evaluated at T1: one week before, T2: mid-, T3: last days of, and T4: one week after Ramadan. The NFG were evaluated only at T1 and T3.

RESULTS

In FG significant alterations of IL-1β was observed. Insignificant differences were found between the FG and NFG at T1 and T3 concerning the measured cytokines. Circulating IL-1β increased significantly from T2 to T4 and from T3 to T4. At T3, TNF-α was correlated significantly with anthropometric parameters such as the body weight, the skeletal muscle mass and the fat free mass, whilst IL-12 was correlated significantly with the skeletal muscle mass, the fat free mass and the body water mass at T4.

CONCLUSIONS

Significant Alterations of IL-1β during RF in FG were observed. Anthropometric parameters correlate with TNF-α and IL-12 levels during at T3 and T4, respectively.

Effectiveness of an intermittent fasting diet versus continuous energy restriction on anthropometric measurements, body composition and lipid profile in overweight and obese adults: a meta-analysis

The effects of an intermittent fasting (IF) diet in the overweight or obese adult population are still controversial. This study aimed to evaluate the effectiveness of an IF diet to reduce anthropometric parameters (body mass index, body weight, and waist circumference), change body composition (fat mass, lean body mass and muscle mass) and lipid profile (total cholesterol, HDL-c, LDL-c and triglycerides), and to adhere to the diet in comparison to continuous energy restriction (CER) in overweight or obese adults. A research question PICO (patients, intervention, comparison, outcome) was established. PubMed, Scopus, Web of Science, Cochrane, and Scielo databases were searched to identify randomized clinical trials that compared an IF diet with a CER diet or a regular diet. DeCS and MeSH descriptors and Boolean operators (AND and OR) were used. From 859 studies identified through the literature search, 18 articles were finally selected. Overall, IF diets were associated with higher weight loss in four studies and similar reduction in waist circumference in one study, compared with a CER regimen. Fat mass tended to decrease more in the IF groups in five studies. However, the lean and muscle mass loss was similar in both groups. Only three studies observed significant differences in lipid profile variables, mostly in the IF groups. Adherence to the diet was inconclusive. An IF diet may provide a benefit by improving anthropometry, body composition, and lipid profile in overweight or obese adult population, likewise a CER diet.

Use of workplace foodservices is associated with reduced meal skipping in Korean adult workers: A nationwide cross-sectional study

Skipping meals is a poor eating behaviour known to result in poor diet quality and health outcomes. Nevertheless, it has become increasingly common over the past few decades in many countries. This study aimed to examine the potential association between the use of workplace foodservices and skipping meals among Korean adult workers using data from the Korea National Health and Nutrition Examination Survey 2016–2018, a nationwide cross-sectional survey of a representative Korean population. A total of 5,137 workers aged 20–64 years were included. Dietary assessment was conducted using a 24-hour dietary recall. In total, 41.2% participants skipped one meal or more per day. The percentage of workers who skipped meals was 43.1±1.0% among participants who did not use workplace foodservices compared to 31.8±1.9% among those who did (P<0.01). Skipping meals was significantly associated with not using workplace foodservices, after adjusting for other confounders including sociodemographic variables, health-related variables, and meal procurement source (odds ratio = 3.4; 95% confidence interval = 2.6–4.4; P<0.01). We found a significant association between using workplace foodservices and reduced skipping meals in Korean adult workers. This study suggests the importance of the provision of workplace foodservices for workers to potentially reduce poor eating behaviours such as skipping meals.

Prevalence of cerebral venous thrombosis with the use of oral contraceptive pills during the Holy month of Ramadan

Objectives:

To identify the epidemiologic profile of cerebral vein thrombosis (CVT) among fasting women using oral contraceptive pills (OCPs) during the holy month of Ramadan.

Methods:

This retrospective study was conducted on all patients diagnosed with CVT and using OCPs from records at a tertiary care hospital in Riyadh, Saudi Arabia during 2016-2017. The study participants were categorized into 2 groups (an intermittently fasting group during the holy month of Ramadan and a non-fasting group).

Results:

Out of 108 female patients with CVT, 36.1% were secondary to OCP, of whom 41% participants were fasting. The most affected site was the transverse sinus. Holocephalic headache was more common amongst fasting group (68.8%) compared to non-fasting group (30.4%) (p=0.025). Dehydration (p=0.003) amongst the fasting group and protein S deficiency (p=0.027) in the non-fasting group were identified as the 2 prominent risk factors. Unfractionated heparin was the most common anticoagulant therapies used during the initiation phase for non-fasting (36.4%) and fasting groups (50%).

Conclusion:

All women who are using OCP should undergo formal written risk assessments for factors of CVT. Our study suggests that the negative effects of OCPs use might outweigh its benefits; thus, it should be prescribed with caution, more so in fasting patients.

From Fad to Fact: Evaluating the Impact of Emerging Diets on the Prevention of Cardiovascular Disease

Cardiovascular disease remains one of the most prevalent and preventable chronic conditions worldwide. Diet modification is the foundation of cardiovascular disease prevention. Several dietary approaches have emerged to promote better cardiovascular health. The rapid dissemination of anecdotal and observational data through the internet and social media has caused confusion amongst providers and patients. The aim of this comprehensive review is to present objective insights into 2 of today's most popular fad diets: ketogenic diet and intermittent fasting. We will evaluate the performance of these diets based on their impact on cardiovascular risk factors.

Effect of Ramadan Fasting on Body Composition, Biochemical Profile, and Antioxidant Status in a Sample of Healthy Individuals

BACKGROUND

Muslims fast during the month of Ramadan by abstinence from food and drink every day from dawn to sunset. Studies have reported contradictory results with respect to the changes in body weight and biochemical parameters. No study has been conducted on the association between fasting and body weight and biochemical parameters in the Indian setting on healthy Muslim subjects.

OBJECTIVES

To assess the effect of fasting during Ramadan on biochemical parameters such as lipid profile, liver function test, renal function test, antioxidant status, random blood sugar, hemoglobin, body composition, and blood pressure in a sample of healthy individuals.

METHODS

In this study, 52 healthy free-living participants (25 males, 27 females, 21-64 years) who met the inclusion and exclusion criteria and completed both follow-ups (before and after Ramadan) were studied. Participants were fasting 12 hours a day for at least 21 days, including menstruating women. It was a free-living study with no dietary restrictions. Anthropometry, lipid profile, liver and renal function tests were measured by standard methods. Body composition was analyzed by bioelectrical impedance.

RESULTS

Significant beneficial changes in albumin, alanine aminotransferase, creatinine, and high-density lipoprotein (HDL) were observed, while total cholesterol, random blood sugar, aspartate aminotransferase, and alkaline phosphatase enzymes remained unchanged after Ramadan. Fasting did bring in some changes in body composition; among both men and women, mean weight loss ranged from 0.81 - 1.4 kg in majority of the subjects, which was due to loss in muscle mass. Moderate changes in intra- and extracellular water content was observed after fasting.

CONCLUSIONS

Significant improvements were observed in HDL levels and liver function tests, which can be attributed to the loss of body weight. Improvement in liver function tests may be related to the changes in cytokines and alteration in sleep patterns. Ramadan-like fasting, along with the nutritional education prior to fasting, may be beneficial and effective in the spiritual and overall well-being.

Association of breakfast skipping with cardiovascular outcomes and cardiometabolic risk factors: an updated review of clinical evidence

"Eat breakfast like a king, lunch like a prince and dinner like a pauper" (Adelle Davis, 1904-1974) is a concept that appears to align with some contemporary evidence concerning the appropriate proportioning of daily meals. At the same time, with the popular and scientific dissemination of the concepts of intermittent fasting and time-restricted feeding, well-controlled clinical trials have emerged showing the safety or even possible benefits of skipping breakfast. In this comprehensive literature review, we discuss recent evidence regarding breakfast intake, cardiovascular outcomes and cardiovascular risk markers. Overall, breakfast omission appears to be associated with a higher risk for atherosclerotic and adverse cardiovascular outcomes. However, caution should be employed when deciphering these data as many complex, unmeasured confounders may have contributed. Unfortunately, long-term randomized, clinical trials with detailed dietary control that have assessed clinical outcomes are sparse. Notwithstanding the observational findings, current trials conducted so far-albeit apparently smaller number-have shown that breakfast addition in subjects who do not habitually consume this meal may increase body weight, particularly fat mass, through caloric excess, whereas skipping breakfast may be a feasible strategy for some people aiming for calorie restriction. To date, definitive benefits of breakfast omission or consumption are not supported by the best evidence-based research, and the question of whether skipping breakfast per se is causally associated with cardiovascular outcomes remains unresolved.

Time-Restricted Feeding Improves Body Weight Gain, Lipid Profiles, and Atherogenic Indices in Cafeteria-Diet-Fed Rats: Role of Browning of Inguinal White Adipose Tissue

Time-restricted feeding (TRF) showed a potent effect in preventing obesity and improving metabolicoutcomes in several animal models of obesity. However, there is, as of yet, scarce evidence concerning its effectiveness against obesogenic challenges that more accurately mimic human Western diets, such as the cafeteria diet. Moreover, the mechanism for its efficacy is poorly understood. White adipose browning has been linked to body weight loss. Herein, we tested whether TRF has the potential to induce browning of inguinal white adipose tissue (iWAT) and to attenuate obesity and associated dyslipidemia in a cafeteria-diet-induced obesity model. Male Wistar rats were fed normal laboratory chow (NC) or cafeteria diet (CAF) for 16 weeks and were subdivided into two groups that were subjected to either ad libitum (ad lib, A) or TRF (R) for 8 h per day. Rats under the TRF regimen had a lower body weight gain and adiposity than the diet-matchedad lib rats, despite equivalent levels of food intake and locomotor activity. In addition, TRF improved the deranged lipid profile (total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL-c), low-density lipoprotein (LDL-c)) and atherogenic indices (atherogenic index of plasma (AIP), atherogenic coefficient (AC), coronary risk index (CRI) in CAF-fed rats. Remarkably, TRF resulted in decreased size of adipocytes and induced emergence of multilocular brown-like adipocytes in iWAT of NC- and CAF-fed rats. Protein expression of browning markers, such as uncoupling protein-1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), were also up-regulated in the iWAToftime-restricted NC- or CAF-fed rats. These findings suggest that a TRF regimen is an effective strategy to improve CAF diet-induced obesity, probably via a mechanismthe involving WAT browning process.

Impact of intermittent fasting on body weight in overweight and obese individuals

OBJECTIVE

To verify the relationship of intermittent fasting in the bodyweight of overweight and obese individuals through a systematic literature review.

METHODS

This is a systematic review based on randomized controlled trials. The articles were consulted in the databases: Science Direct, PubMed e BVS. This review was evaluated through the PRISMA recommendation.

RESULTS

After the selection process, four articles were included in this review, comparing intermittent fasting (IF) with calorie restriction diet (CRD) as a control group. In 2 studies using similar protocols, there was no significant reduction in body weight of overweight or obese subjects. In the other two studies using different protocols, weight loss was significant in the IF group compared to the CRD group.

CONCLUSIONS

Results did not provide evidence of the effect of intermittent fasting on weight loss in overweight or obese individuals.

Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis

OBJECTIVES

To the best of our knowledge, no systematic review and meta-analysis has evaluated the cholesterol-lowering effects of intermittent fasting (IF) and energy-restricted diets (ERD) compared with control groups. The aim of this review and meta-analysis was to summarize the effects of controlled clinical trials examining the influence of IF and ERD on lipid profiles.

METHODS

A systematic review of four independent databases (PubMed/Medline, Scopus, Web of Science and Google Scholar) was performed to identify clinical trials reporting the effects of IF or ERD, relative to non-diet controls, on lipid profiles in humans. A random-effects model, employing the method of DerSimonian and Laird, was used to evaluate effect sizes, and results were expressed as weighted mean difference (WMD) and 95% confidence intervals (CIs). Heterogeneity between studies was calculated using Higgins I², with values ≥50% considered to represent high heterogeneity. Subgroup analyses were performed to examine the influence of intervention type, baseline lipid concentrations, degree of energy deficit, sex, health status, and intervention duration.

RESULTS

For the outcomes of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triacylglycerols (TG), there were 34, 33, 35, and 33 studies meeting all inclusion criteria, respectively. Overall, results from the random-effects model indicated that IF and ERD interventions resulted significant changes in TC (WMD, -6.93 mg/dL; 95% CI, -10.18 to -3.67; P < 0.001; I² = 78.2%), LDL-C (WMD, -6.16 mg/dL; 95% CI, -8.42 to -3.90; P ˂ 0.001; I² = 52%), and TG concentrations (WMD, -6.46 mg/dL; 95% CI, -10.64 to -2.27; P = 0.002; I² = 61%). HDL-C concentrations did not change significantly after IF or ERD (WMD, 0.50 mg/dL; 95% CI, -0.69 to 1.70; P = 0.411; I² = 80%). Subgroup analyses indicated potentially differential effects between subgroups for one or more lipid parameters in the majority of analyses.

CONCLUSIONS

Relative to a non-diet control, IF and ERD are effective for the improvement of circulating TC, LDL-C, and TG concentrations, but have no meaningful effects on HDL-C concentration. These effects are influenced by several factors that may inform clinical practice and future research. The present results suggest that these dietary practices are a means of enhancing the lipid profile in humans.

Effects of time-restricted feeding on body weight and metabolism. A systematic review and meta-analysis

Restriction in meal timing has emerged as a promising dietary approach for the management of obesity and dysmetabolic diseases. The present systematic review and meta-analysis summarized the most recent evidence on the effect of time-restricted feeding (TRF) on weight-loss and cardiometabolic variables in comparison with unrestricted-time regimens. Studies involving TRF regimen were systematically searched up to January 2019. Effect size was expressed as weighted mean difference (WMD) and 95% confidence intervals (CI). A total of 11 studies, 5 randomized controlled trials and 6 observational, were included. All selected studies had a control group without time restriction; hours of fasting ranged from 12-h until 20-h and study duration from 4 to 8-weeks. Most studies involved the Ramadan fasting. TRF determined a greater weight-loss than control regimens (11 studies, n = 485 subjects) (WMD: -1.07 kg, 95%CI: -1.74 to -0.40; p = 0.002; I² = 56.2%), unrelated to study design. The subgroup analysis showed an inverse association between TRF and fat free mass in observational studies (WMD: -1.33 kg, 95%CI: -2.55 to -0.11; p = 0.03; I² = 0%). An overall significant reduction in fasting glucose concentrations was observed with TRF regimens (7 studies, n = 363 subjects) (WMD: -1.71 mg/dL, 95%CI: -3.20 to -0.21; p = 0.03; I² = 0%), above all in trials (WMD:-2.45 mg/dL, 95%CI: -4.72 to -0.17; p = 0.03; I² = 0%). No between-group differences in the other variables were found. TRF regimens achieved a superior effect in promoting weight-loss and reducing fasting glucose compared to approaches with unrestricted time in meal consumption. However, long-term and well-designed trials are needed to draw definitive conclusions.

Metabolic Effects of Fasting and Animal Source Food Avoidance in an Ethiopian Adult Cohort

Fasting is a religious practice to which the faithful comply strictly. The longest period of fasting in Orthodox religion is the lent (in Ethiopia known as “Hudade”). According to the doctrine of Ethiopian Orthodox Christianity, fasters should strictly avoid all animal source foods (ASF) and skip breakfast at least up to lunch time. This can be taken as a well-controlled natural experiment to evaluate the effect of breakfast skipping and avoidance of ASF for 55 days. However, there is no study that evaluated the effect of ASF fasting (avoidance of animal source foods  and breakfast skipping) on lipid profiles, fasting blood sugar and body composition in Ethiopian set up. A retrospective cohort study was carried out among 704 employees of Jimma University (253 fasters and 451 non-fasters) from February 2015 to April 2015. Data on socio-demographic, anthropometry, blood pressure and blood samples were collected according to WHO STEPS procedure. Descriptive statistics and multivariable linear regression models were used to compare the effect of fasting on outcome variables. There was a significant difference in the body fat percent (mean ± sd) between non-fasters (32.35 ± 11.12) and fasters (30.59 ± 11.22, P = 0.045). Similarly, the mean ± sd waist circumference was higher among non-fasters (84.96 ± 11.43 cm) compared to fasters (83.04 ± 11.43 cm, P < 0.033). High density lipoprotein was significantly (P = 0.001) high among fasters (68.29 mg/dl) compared to non-fasters (57.24 mg/dl). Total cholesterol (T.chol) was also higher among non- fasters (181.01 mg/dl) than fasters (173.80 mg/dl, P = 0.035). The mean Triglyceride level was significantly (P = 0.035) high among non-fasters (142.76 mg/dl) compared to fasters (129.39 mg/dl). Similarly, fasting blood sugar was high among non-fasters (100.14 mg/dl) compared to fasters (95.11 mg/dl), P = 0.009. On multivariable linear regression analyses after adjusting for different variables, fasters had a significantly high mean HDL and lower mean T.chol, Triglycerides, FBS and LDL levels. Similarly, fasters had a significantly low mean waist circumference and low mean body fat percent (P < 0.05). In conclusion, animal source food avoidanceand breakfast skipping has a significant desirable health effects on lipid profiles, fasting blood sugar and body composition. The findings imply the need for considering such a dietary practice as a basis for public health promotion. Future research should investigate the effect of ASF fasting and breakfast skipping on micronutrient intake and determine the minimum number of days of fasting required to generate clinically significant effects.

Short-term Intermittent Fasting for Weight Loss: A Case Report

Intermittent fasting, in which individuals fast periodically, is an increasingly popular weight loss regimen. To understand the short-term effects of such a regimen, we present a case of intermittent fasting with data collection that mimics the single-case design. A healthy but slightly overweight adult male underwent complete fast for two full days and resumed with normal eating for five days, and repeated the cycle three times. Data were collected from three periods: baseline (one week); fasting (three weeks); post-fasting (one week). Measurements taken daily include weight, body fat ratio, temperature, blood pressure, blood glucose, as well as waist and hip circumferences. Blood tests were conducted weekly for safety screening and to obtain observations on lipid profile, high-sensitive C-reactive protein (hsCRP), hemoglobin A1c (HbA1c), and uric acid.  The participant lost 1.3 kilograms (kg) in body weight (W̅b = 65.9kg vs W̅p = 64.6kg). Body fat ratio did not differ much (F̅Rb = 19.1% vs F̅Rp = 18.8%). Fasting caused an acute drop in the blood glucose level, which was restored upon resuming normal eating. Total cholesterol dropped drastically immediately after the first fasting cycle but rebounded 15% higher than baseline before dropping down. Fasting also temporarily raised uric acid levels, blood pressure, and body temperature. HbA1c and waist and hip circumferences were not affected by fasting. Improvement in inflammatory marker (hsCRP) was observed (2.0 to 0.3 milligrams per liter, mg/L). This case demonstrates that intermittent fasting can induce short-term weight loss and reduce acute inflammatory marker in a healthy adult, but not body fat ratio and lipid profile. Similar single-case study design can be applied across a practice-based network for inter-case replication.

Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials

Background

This systematic review and meta-analysis summarized the most recent evidence on the efficacy of intermittent energy restriction (IER) versus continuous energy restriction on weight-loss, body composition, blood pressure and other cardiometabolic risk factors.

Methods

Randomized controlled trials were systematically searched from MEDLINE, Cochrane Library, TRIP databases, EMBASE and CINAHL until May 2018. Effect sizes were expressed as weighted mean difference (WMD) and 95% confidence intervals (CI).

Results

Eleven trials were included (duration range 8–24 weeks). All selected intermittent regimens provided ≤ 25% of daily energy needs on “fast” days but differed for type of regimen (5:2 or other regimens) and/or dietary instructions given on the “feed” days (ad libitum energy versus balanced energy consumption). The intermittent approach determined a comparable weight-loss (WMD: − 0.61 kg; 95% CI − 1.70 to 0.47; p = 0.87) or percent weight loss (WMD: − 0.38%, − 1.16 to 0.40; p = 0.34) when compared to the continuous approach. A slight reduction in fasting insulin concentrations was evident with IER regimens (WMD = − 0.89 µU/mL; − 1.56 to − 0.22; p = 0.009), but the clinical relevance of this result is uncertain. No between-arms differences in the other variables were found.

Conclusions

Both intermittent and continuous energy restriction achieved a comparable effect in promoting weight-loss and metabolic improvements. Long-term trials are needed to draw definitive conclusions.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1748-4) contains supplementary material, which is available to authorized users.