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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,
Content may be subject to copyright.
published: 01 February 2021
doi: 10.3389/fnut.2020.596787
Frontiers in Nutrition | 1February 2021 | Volume 7 | Article 596787
Edited by:
Kelly Costello Allison,
University of Pennsylvania,
United States
Reviewed by:
Ulrich Schweiger,
Helios Hanseklinikum, Germany
Marie-Pierre St-Onge,
Columbia University, United States
Jena Shaw Tronieri,
University of Pennsylvania,
United States
Naseer Ahmed
Specialty section:
This article was submitted to
Eating Behavior,
a section of the journal
Frontiers in Nutrition
Received: 20 August 2020
Accepted: 23 December 2020
Published: 01 February 2021
Ahmed N, Farooq J, Siddiqi HS,
Meo SA, Kulsoom B, Laghari AH,
Jamshed H and Pasha F (2021)
Impact of Intermittent Fasting on Lipid
Profile–A Quasi-Randomized Clinical
Trial. Front. Nutr. 7:596787.
doi: 10.3389/fnut.2020.596787
Impact of Intermittent Fasting on
Lipid Profile–A Quasi-Randomized
Clinical Trial
Naseer Ahmed 1
*, Javeria Farooq 1, Hasan Salman Siddiqi 1, Sultan Ayoub Meo 2,
Bibi Kulsoom 3, Abid H. Laghari 4, Humaira Jamshed 5and Farooq Pasha 6
1Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan, 2Department of Physiology,
College of Medicine, King Saud University, Riyadh, Saudi Arabia, 3Postgraduate Programme-Training and Monitoring, Bahria
University Medical and Dental College, Karachi, Pakistan, 4Department of Medicine, Section of Cardiology, Aga Khan
University, Karachi, Pakistan, 5Integrated Sciences and Mathematics, Dhanani School of Science and Engineering, Habib
University, Karachi, Pakistan, 6Economics, Boston College, Chestnut Hill, MA, United States
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 (ps <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://
Keywords: intermittent fasting, lipid profile, weight reduction, cardioprotection, healthy life style
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
It is well-documented that dyslipidemia, characterized by high
concentration of serum total cholesterol (TC), low-density
lipoprotein cholesterol (LDL-C) and triglycerides (TG) with low
levels of high-density lipoprotein cholesterol (HDL-C), is linked
to cardiovascular disease (CVD) (1). Some studies have shown
that low HDL-C, with normal LDL-C and triglyceride levels can
be as dangerous for coronary health as high LDL-C (2,3). HDL-
C reverses cholesterol transport and reduces the atherosclerotic
burden. HDL-C also has anti-inflammatory, anti-oxidative, anti-
thrombotic, anti-apoptotic, and vasodilatory properties (4).
Various alternative ways for managing dyslipidemia include
life style modification, regular exercise and moderate alcohol
consumption (5).
Intermittent fasting (IF) can be adopted as a life style
modification for good health and balanced lipid profile. IF is
type of energy restricted feeding protocol known since long
from religious and cultural backgrounds. IF has been extensively
studied in animal models. Such studies indicate that IF improves
lipid profile (6), protects the heart from ischemic injury, and
attenuates post-MI cardiac remodeling (7). Various scientific
studies have been conducted on humans to identify the role
of different IF methods including alternate day fasting, caloric
restriction, Ramadan fasting and periodic fasting etc. Alternate-
day fasting (ADF) reduces body weight by 3–7% over 2–3
month, and improves lipid profiles and blood pressure. It was
suggested that fasting positively impacts metabolic biomarkers
and cardiovascular health while long term effects should be
explored (8). A clinical trial of ADF in adults with obesity found
it as an effective method for weight reduction and reduction in
coronary artery disease risks (9). Additionally, one clinical trial
found ADF effective for weight reduction in people with normal
and overweight (10). Combination of alternate day fasting with
physical activity reports greater changes in body composition and
plasma lipid profile and reduces cardiovascular risk as compared
to individual treatments (11). Keogh et al. found that IF is as
effective for weight management as continuous calorie restriction
for 8 weeks (12). The reduced caloric intake and weight loss
might explain the effects of IF on the lipid profile which may be
translated to improvements in cardio metabolic health (13).
Ramadan fasting studies have shown mixed effects on health.
Some studies found reduction in body weight (14) while others
report minimal change (15). Similar inconsistencies are reported
for the lipid profile and blood glucose levels as well. One
explanation could be the confounding variables such as the
fasting duration, medications, dietary habits, cultural norms and
physical activity (16). Other factors may include methodological
differences, seasonal changes, geographical location, daylight
exposures etc.
The current study trial was designed to investigate the effects
of IF on lipid profile in adults. It was hypothesized that IF
will improve the lipid profile and might prevent cardiovascular
diseases. The study protocol was different from other previously
studied IF methods as it required day time 12 h fasting for 3 days
a week for 6 weeks. It had similarity with Ramadan fasting in that
the fast was kept from sunrise to sunset but it was different from
Ramadan fasting in the aspect that Ramadan fasting requires
daily fasting for four continuous weeks. In this study, IF was
defined as fasting for 3 days in a week for 6 weeks.
Study Design
This was a quasi-experimental clinical study conducted on
employees of the Aga Khan University Hospital. People were
informed through emails, phone calls and personal contacts. The
Declaration of Helsinki and Good Clinical Practice guidelines
was followed. After explaining the study protocol to the
participants, written informed consent was collected. Participants
did not receive any incentive, monetary or otherwise, for
participating in this study. Sample size was calculated by
reviewing the previous intermittent fasting trial sample sizes
(17,18). The power of the study for significant improvement in
HDL cholesterol was 80%, with a significance level of 5%.
Inclusion criteria included age of 20–70 years, with serum HDL <
40 mg/dl for men and <50 mg/dl for women. Pregnant women
and individuals with self-reported cardiovascular diseases or any
other co-morbidity were excluded. Screening was performed and
lipid profile was conducted to confirm HDL levels. A total of 40
subjects (20 in each group) were enrolled in the study.
Data Collection
The employees who agreed to participate in the trial were called
for screening. They were asked to bring their lipid profile result
from the last 4 weeks, if available. The individuals without such
previous lipid profile reports were asked to come after 10–12 h of
fasting so that a lipid profile test could be performed. Individuals
with low HDL levels indicated either by the previous reports
or by currently performed screening lipid profiles were enrolled
in the study. Screening and enrolment were completed in 3–4
weeks. Then enrolled participants were invited to a designated
room in the Multidisciplinary laboratory of Aga Khan University
where questionnaires regarding participants’ eating routine and
physical activity of participant were completed. Body weight,
waist circumference, height and blood pressure were measured.
Body fat and water content were measured by an impedance
scale. Blood was collected for lipid profile testing and glucose
estimation. Participants were called again after 6-weeks whereby
the same body parameters were measured and fasting blood
was collected.
Intervention and Control
The participants were distributed into two groups according
to their group preference; Control and Intervention. Informed
consent form was signed by all the participants. Intervention
group was advised to fast for 12 h during day time (6 A.M.6
P.M.) for only 3 days/week for 6 weeks. The intervention group
was instructed to take their routine diet in the non-fasting
period. The control group continued their usual dietary pattern
and were advised to make no changes in lifestyle. Compliance
Frontiers in Nutrition | 2February 2021 | Volume 7 | Article 596787
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
was monitored through phone calls and messages every week
for 6 weeks. Although there are no reported adverse effects of
intermittent fasting, the contact number of a doctor was given
to participants in case of any emergency or concern.
TABLE 1 | Baseline description of participants.
Parameters Control Intermittent
trial (n=15)
Age (year) 42.30 ±13.50 36.05 ±12.06 37.80 ±12.25
Male 12 13 8
Female 8 7 7
BMI (kg/m2)
Underweight 1 1 1
Normal 8 6 2
Overweight 10 11 10
Obese 1 2 2
Blood Pressure
Systolic 120.90 ±15.41 115.11 ±13.69 114.93 ±13.86
Diastolic 80.65 ±8.18 80.39 ±6.71 79.80 ±5.73
Health condition
Yes: No Yes: No Yes: No
Dyslipidemia 20:00 20:00 15:00
Hypertension 3:17 0:20 0:15
Diabetes mellitus 0:20 0:20 0:15
Cigarette smoking 2:18 0:20 0:15
Family history of
2:18 3:17 3:12
Ethical Consideration
The clinical trial was approved by Ethics Review
Committee of Aga Khan University Hospital with
registration number ERC # 2019-0633-2318. The trial
TABLE 3 | Mean difference in parameters after (post) and before (baseline)
intermittent fasting with Control (n=20) and IF (n=15).
Parameters Groups Mean difference P-value
Body weight (kg) Control 0.05 ±0.16 0.757
IF 3.10 ±0.19 0.0001**
BMI (kg/m2) Control 0.04 ±0.11 0.725
IF 0.98 ±0.13 0.0001**
Waist circumference(cm)Control 0.11 ±0.16 0.480
IF 0.98 ±0.18 0.0001**
Body Fat (%) Control 0.11 ±0.35 0.760
IF 0.51 ±0.40 0.215
Total cholesterol (mg/dl)Control 2.69 ±3.92 0.498
IF 16.08 ±4.53 0.001*
Triglycerides (mg/dl)Control 1.68 ±3.95 0.673
IF 12.82 ±4.57 0.008*
LDL (mg/dl)Control 2.49 ±1.85 0.187
IF 5.24 ±2.14 0.020*
HDL (mg/dl)Control 0.46 ±0.24 0.062
IF 3.04 ±0.27 0.0001**
Blood glucose (mg/dl)Control 0.63 ±1.63 0.703
IF 0.62 ±1.89 0.745
Results are presented as mean±SEM. IF, intermittent fasting group; *p<0.05, **p<
0.001; parameters with symbol represents adjustment with body weight.
TABLE 2 | Changes in parameters before (baseline) and after (post) intermittent fasting with Control (n=20) and IF (n=15).
Parameters Groups Baseline Post Interaction effect Time effect
(Time x group)
Body weight (kg) Control 73.07 ±11.63 73.03 ±11.56 0.0001** 0.0001**
IF 75.73 ±12.78 72.63 ±12.23
BMI (kg/m2) Control 25.67 ±3.58 25.63 ±3.50 0.0001** 0.0001**
IF 27.62 ±4.14 26.64 ±4.01
Waist circumference(cm)Control 34.57 ±4.39 34.44 ±4.46 0.001* 0.111
IF 34.73 ±4.74 33.77 ±4.75
Body fat (%) Control 31.29 ±8.02 31.40 ±7.94 0.255 0.456
IF 31.87 ±6.14 31.36 ±7.17
Total cholesterol (mg/dl)Control 185.00 ±36.27 182.40 ±34.48 0.033* 0.859
IF 198.29 ±38.82 182.09 ±30.56
Triglycerides (mg/dl)Control 138.70 ±78.30 137.00 ±74.57 0.075 0.662
IF 135.60 ±60.13 122.80 ±61.48
LDL (mg/dl)Control 102.32 ±26.27 104.69 ±24.42 0.010* 0.333
IF 111.04 ±40.71 105.95 ±33.04
HDL (mg/dl)Control 34.45 ±6.81 34.01 ±6.48 0.0001** 0.055
IF 35.60 ±6.45 38.62 ±6.45
Blood glucose (mg/dl)Control 82.35 ±11.90 81.83 ±7.69 0.623 0.339
IF 80.40 ±10.78 80.87 ±10.04
Results are presented as mean ±SD. IF, intermittent fasting group; *p<0.05, **p<0.001; parameters with symbol represents adjustment with baseline body weight of the entire sample.
Frontiers in Nutrition | 3February 2021 | Volume 7 | Article 596787
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
was registered at NIH, US National Library of Medicine
as NCT03805776. The study protocol was explained in
detail to all the participants. Privacy and confidentiality
was maintained.
Sample Analysis
Blood samples were centrifuged on the day of collection at 2500
RPM for 15 min at 4C. Serum was separated in aliquots and was
stored at 20C for lipid analysis. For performing lipid profile
test, cobas c 111 kits (Roche diagnostics, made in Germany) was
used with cobas c 111 automated analyzer (Roche Cobas).
Data Analysis
Data were analyzed using IBM SPSS Statistics 20 and GraphPad
Prism 8. Data are presented as mean ±standard deviation (SD)
in Tables 1,2and figures. However, in Table 3 data is presented
as mean difference ±standard error mean (SEM). The level of
significance was set to α < 0.05 for all performed two-sided
tests. To detect changes over time and respective differences
between the groups, a repeated-measures ANOVA (rmANOVA)
with factors time (pre, post) ×group (IF, Control) was performed
to test for interaction effects. In the case of significant interaction
effects from the rmANOVA, Bonferroni corrected Student’s t-
tests were calculated for any pre to post differences. For metabolic
risk factors, data have been adjusted with mean of body weight of
the entire sample at baseline.
Out of 70 individuals, 40 fulfilled the inclusion criteria and
were enrolled in the study – 20 in each group. Thirty-five
FIGURE 1 | Flow chart of the study trial.
Frontiers in Nutrition | 4February 2021 | Volume 7 | Article 596787
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
FIGURE 2 | Multiplot figure of body measurements and blood glucose level of control and intervention group at baseline and post study. *p<0.05, **p<0.001.
participants (87.5%) completed the study. Five dropouts from the
intervention group were due to personal reasons or inability to
comply with the fasting regime. Figure 1 summarized the flow of
participants through the study.
The baseline description of participants including age, gender,
blood pressure, BMI level and details of their existing medical
condition is represented in Table 1. The detailed questionnaire
regarding eating routines and physical activity at baseline level
and after post study showed no difference, all the participants
followed their same daily routines as advised.
Table 2 summarize the changes in parameters at baseline
and post 6 weeks study. Body measurements including body
weight and BMI showed significant interaction effects (p=
0.0001) and time effects (p=0.0001) while waist circumference
showed significant interaction effect (p=0.001) only. Significant
interaction effects were exhibited by HDL (p=0.0001), total
cholesterol (p=0.033) and LDL (p=0.010) with non-significant
time effects. Furthermore, body fat, triglycerides and blood
glucose did not show any significant interaction effects.
Table 3 shows the mean changes in body measurements,
lipids, and blood glucose levels from baseline to post-treatment
for the control and intervention groups and the results of post-hoc
analyses of within-group change. The IF group had significant
reductions in body weight (3.10 ±0.19 kg; p=0.0001), BMI
(0.98 ±0.13 kg/m2;p=0.0001) and waist circumference
(0.98 ±0.18 cm; p=0.0001). The mean differences for IF
group were also significant for total cholesterol (16.08 ±4.53
mg/dl; p=0.001), HDL (3.04 ±0.27 mg/dl (p=0.0001), LDL
(5.24 ±2.14 mg/dl; p=0.020) and triglycerides (12.82 ±
4.57 mg/dl; p=0.008). There were no significant changes for any
of the parameters for the control group. However, it should be
noted that the between-group difference in change did not reach
statistical significance for triglycerides.
Figures 2,3represent the comparison of changes in body
measurements, lipid and blood glucose levels of control and
intervention groups at baseline and post intervention with
significance level of interaction effect.
The study suggests that IF has the potential of improving the
lipid profile and reducing body weight and waist circumference.
Frontiers in Nutrition | 5February 2021 | Volume 7 | Article 596787
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
FIGURE 3 | Multiplot figure of lipid levels of control and intervention group at baseline and post study. *p<0.05, **p<0.001.
These results are in line with other studies showing that different
types of IF, including Ramadan fasting and alternative day fasting,
reduce body weight and lipid levels (17,19). Studies combining
IF with physical activity (11) and comparing different types of IF
(12) also suggest that IF can be an effective lifestyle modification
for reducing the risks of cardiovascular diseases. However, most
of the IF clinical trials in the literature were conducted for short
periods of time and large scale randomized controlled trials
with longer duration and follow-ups are not available. Long
term studies should be conducted to validate their effectiveness
and safety.
Santos et al. have compiled data from different trials and
concluded that different types of IF can increase HDL by 1–
14 mg/dl, decrease LDL by 1–47 mg/dl, decrease TC by 5–88
mg/dl and decrease TG by 3–64 mg/dl (18). As compared to
the other types of IF, our method appears safe, effective and
can be adopted in daily life, without any additional financial
or physical burden. Individuals can incorporate IF into their
lifestyles without worrying about any extra efforts to prepare
low calorie meals. The 12-h fast might be maintained by an
early breakfast and having dinner at an appropriate time, which
works for weekdays and weekends. However, it might be difficult
for people working late nights or having an active social life
with frequent dining out routines. This was also observed in the
current study; 5 people dropped out from the study due to their
hectic and busy schedule and could not maintain fasting period
for 3 day/week.
Previously conducted trials have mentioned that intermittent
fasting of 12–36 h results in a metabolic switch (20) leading to
a break down of triglycerides into fatty acids and glycerol and
conversion of fatty acids to ketone bodies in the liver (21). During
fasting, fatty acids and ketone bodies provide energy to cells
and tissues (22). Studies suggested that molecule modulation
in the liver leads to expression of PPARa and PGC-1a that
increases fatty acid oxidation and apoA production leading to
increased HDL levels, whereas apoB decreases which causes
decreased hepatic triglycerides and LDL levels (23,24). Shibata
and colleagues worked on SREPB-2, Sterol regulatory element-
binding protein in mice, and suggested that intermittent fasting
can lead to reduction in cholesterol by regulating SREPB-2 (25).
The main limitations of this study included non-
randomization of the study population. Moderate to severe
dyslipidemic patients were not included in the study. Other
major limitation was the drop out of five participants from the
Frontiers in Nutrition | 6February 2021 | Volume 7 | Article 596787
Ahmed et al. Intermittent Fasting Effect on Lipid Profile
intervention group of the study which may have inflated the
size of the results. It was a single centered and small-scale study
lacking data on food intake and record of caloric intake.
Restriction of food intake for 12-h/day for 3 days/week leads to
weight reduction and improvement in lipid profile, particularly
HDL, which can reduce the risk of cardiovascular diseases. Future
studies including randomized controlled trials with more diet
control, longer follow ups and individuals with cardiovascular
diseases and type 2 diabetes mellitus are warranted to validate
these findings.
The raw data supporting the conclusions of this article will be
made available by the authors, without undue reservation.
The studies involving human participants were reviewed and
approved by Ethical Review Committee of Aga Khan University.
The patients/participants provided their written informed
consent to participate in this study.
NA conceived the idea, designed and conducted the trial,
provided the funding support, and supervised the study. JF
conducted the study, managed the project and participants, and
drafted the manuscript. HS, BK, and AHL helped in conducting
the clinical trial, data interpretation, and manuscript review. HJ
reviewed and revised the draft of the manuscript. FP performed
the statistical analysis. SAM provided intellectual input and
resources for performing some analysis. All authors contributed
to the article and approved the submitted version.
We would like to acknowledge the Researchers Supporting
Project Number (RSP-2019/47), King Saud University, Riyadh,
Saudi Arabia. We are also thankful to Prof. Anwar-ul Hassan
Gilani and Prof. Perwaiz Iqbal for their intellectual input,
mentorship and constant support and guidance, and Mr. Ghulam
Haider and MDL/ML lab staff for technical support.
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Conflict of Interest: The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could be construed as a
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Frontiers in Nutrition | 8February 2021 | Volume 7 | Article 596787
... The flexibility of these internal clocks is mandatory, in terms of connecting the SCN signals to the hunger and satiety center located also in the hypothalamus, instructing the relevant organs to act at the solicited time. After a desynchronizing event, the downstream reverberations are perceived slowly, but firmly, and the system resets itself within a few days, for example, midnight nutrients ingestion resets the gut and liver clocks in less than a week, aligning the metabolic machinery to the new consumption pattern [9][10][11][12]. ...
... Furthermore, PER1 activity regulates Sglt1 independently of the E-box. Following a scheduled feeding experiment, it has been concluded that feeding circumstances directly impact these transporters [9]. ...
... This dietary habit also changes the liver clock and the hepatic rhythmicity of lipid metabolism. The influence of meal timing on lipid metabolism is not considered highly significant, while the importance of well-regulated eating habits is recognized [9]. Therefore, the influence of meal timing was examined using genetically unmodified animals. ...
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New scientific evidence raises awareness concerning the human-specific interplay among primary environmental conditions, such as the light–dark cycle, activity–rest alternation, nutritional patterns, and their reflection on the physiological and pathological characteristics that are displayed uniquely by every individual. One of the critical aspects in the clinic is to understand the role of circadian rhythms as remarkable modulators of the biological effects of drugs and to aim for an optimal overlapping of the time of administration of medicines with the physiologic release of certain hormones, the time-dependent expression of genes, or the key-regulatory protein synthesis, which are all circadian-driven processes. The pharmacokinetics and pharmacodynamics profiles, as well as the possible drug interactions of neurotropic and cardiovascular agents, are intensely subjected to endogenous circadian rhythms, being essential to identify as much as possible the patients’ multiple risk factors, from age and gender to lifestyle elements imprinted by dietary features, sleep patterns, psychological stress, all the way to various other associated pathological conditions and their own genetic and epigenetic background. This review chapter will highlight the involvement of biological rhythms in physiologic processes and their impact on various pathological mechanisms, and will focus on the nutritional impact on the circadian homeostasis of the organism and neurologic and cardiovascular chronotherapy.
... Intermittent fasting can be a therapeutic strategy to achieve better serum lipid profiles and cardiovascular protection [69][70][71] in obese patients at higher CV risk. There is still no solid evidence for the use of IF in clinical practice, however, as most knowledge comes from anecdotal and observational studies or from the experience of patients observing the fasting customs of Ramadan [72,73,[579][580][581][582]. ...
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Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.
... Numerous treatments for these kinds of diseases mostly focus on diet and exercise (2,3). Intermittent fasting (IF) has become a popular lifestyle in recent years, though it has existed in religious and cultural contexts for a long time (4,5). IF is a term that covers several specific patterns (6,7). ...
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Background The popularity of applying intermittent fasting (IF) has increased as more and more people are trying to avoid or alleviate obesity and metabolic disease. This study aimed to systematically explore the effects of various IF in humans. Methods The randomized controlled trials (RCTs) related to IF vs. non-intervention diet or caloric restriction (CR) were retrieved in PubMed, Web of Science, Cochrane Library database, and Embase. Extraction outcomes included, but were not limited to, weight, body mass index (BMI), waist circumference (WC), fasting glucose, and triglyceride (TG). Results This study includes 43 RCTs with 2,483 participants. The intervention time was at least 1 month, and the median intervention time was 3 months. Contrasting results between IF and non-intervention diet showed that participants had lower weight (weighted mean difference (WMD) = 1.10, 95% CI: 0.09–2.12, p = 0.03) and BMI after IF (WMD = 0.38, 95% CI: 0.08–0.68, p = 0.01). The WC of participants after IF decreased significantly compared with the non-intervention diet (WMD = 1.02, 95% CI: 0.06–1.99, p = 0.04). IF regulated fat mass (FM) more effectively than non-intervention diet (WMD = 0.74, 95% CI: 0.17–1.31, p = 0.01). The fat-free mass of people after IF was higher (WMD = −0.73, 95% CI: (−1.45)–(−0.02), p = 0.05). There was no difference in fasting blood glucose concentrations between participants in the after IF and non-intervention diet groups. The results of insulin concentrations and HOMA-IR, though, indicated that IF was significantly more beneficial than non-intervention diet (standard mean difference (SMD) = −0.21, 95% CI: 0.02–0.40, p = 0.03, and WMD = 0.35, 95% CI: 0.04–0.65, p = 0.03, respectively). Cholesterol and TG concentrations in participants after IF were also lower than that after a nonintervention diet (SMD = 0.22, 95% CI: 0.09–0.35, p = 0.001 and SMD = 0.13, 95% CI: 0.00–0.26, p = 0.05, respectively). IF outcomes did not differ from CR except for reduced WC. Conclusion Intermittent fasting was more beneficial in reducing body weight, WC, and FM without affecting lean mass compared to the non-intervention diet. IF also effectively improved insulin resistance and blood lipid conditions compared with non-intervention diets. However, IF showed less benefit over CR.
... As Cuccolo notes [24], there is a wealth of literature focused very specifically on whether and how intermittent fasting produces clinical changes in different contexts and with different biomarkers. For instance, in terms of lipid profiles, intermittent fasting was shown to be effective in improving total cholesterol, low-density lipoprotein cholesterol, and triacylglycerol concentrations [25,26]. Intermittent fasting was associated with greater weight loss in patients with diabetes compared with a regular diet [27]. ...
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Background There is a dearth of studies on intermittent fasting in Saudi Arabia outside of Ramadan. The aim of this research was to study and describe the practice of intermittent fasting outside of Ramadan among Saudi people. Methods A web-based survey that focused on intermittent fasting practices—specifically the use of intermittent fasting applications, goal setting, and the effects of fasting on an individual’s state of health—was administered, collected, and analyzed. Results The study revealed that 58% (298/514) of the respondents practiced intermittent fasting for a duration of less than 3 months. The most-practiced pattern of intermittent fasting was a 16/8 fasting pattern (43.8%, 225/514). About 88.3% (454/514) of those who followed intermittent fasting drank fluids while fasting. Additionally, the amount of weight loss after intermittent fasting was less than 2.2 kg for 35% (180/514) of the participants. The primary goal of intermittent fasting for 44.9% (231/514) of the respondents was to lose weight. The majority of the participants (84.6%, 435/514) did not use any fasting applications. Conclusion The results of the current research on intermittent fasting outside of Ramadan are preliminary and inconclusive. The findings of the present study advance the idea that for some Saudis, the practice of intermittent fasting does not necessarily begin and end with Ramadan; this finding may present a strategic opportunity for Saudi health professionals who are focused on the obesity epidemic and other public health issues in Saudi Arabia. This study sought to help start a discussion on this topic and fill the knowledge gap.
... However, it should be taken into account that younghealthy students tend to prefer more lenient RF, whereas older subjects often practice a more strict type of RF. The promising utility of RF as a complementary life-style tool for the management of dyslipidemia is reinforced by other studies concerning plantbased and restricting fasting diets [9,10,[22][23][24][25], even if it is still unclear whether the effects of vegan and vegetarian diets on metabolic parameters equal RF ones. A large systematic review and meta-analysis concerning lipid concentrations in individuals having Table 5 summarizes the bootstrapped multivariate linear regression models created to predict the A. B12, B. Triglyceride, C. LDL cholesterol and D. HDL cholesterol levels after the completion of the seven-week-long Orthodox religious fasting period. ...
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Religious fasting (RF) is practiced annually by millions of Christian and Muslim followers worldwide. Scarce data exist on the impact of RF on the metabolic and hematological profile of individuals with or without dyslipidemia. The present study included: (i) 60 Greek Orthodox participants, 30 with dyslipidemia and 30 without dyslipidemia, who abstained from meat, fish and dairy products for seven consecutive weeks, and (ii) 15 young, non-dyslipidemic Muslim participants abstaining totally from food and liquid from dawn till sunset during 30 days. Biochemical (iron, ferritin, vitamin B12, calcium, low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), triglyceride and fasting glucose) and hematological (hemoglobin, hematocrit) serum blood test results of study participants were measured pre- and post- RF (at weeks 0 and 7 for Orthodox participants and at weeks 0 and 4 for Muslim participants). In dyslipidemic and non-dyslipidemic Orthodox participants, a significant reduction of fasting glucose, HDL, LDL and TC levels was found post-RF. Hemoglobin, hematocrit, iron and ferritin levels were significantly increased, while post-RF vitamin B12 and calcium levels were substantially decreased. Subanalysis between dyslipidemic and non-dyslipidemic Orthodox participants revealed a greater decrease of cholesterol levels in the former. In Muslim participants, triglyceride, LDL and total cholesterol levels were increased post-RF (all p values < 0.05). Our study adds to the existing literature evidence about the significant impact of RF on metabolic and hematological profiles of Orthodox and Muslim followers. The prevention of calcium and B12 deficiency during Orthodox RF by supplement consumption as well as the protection from dehydration and dysregulation of lipid metabolism during Ramadan RF should concern both clinicians and dietician nutritionists. Nevertheless, studies with larger sample size and/or long-term follow-up are warranted before reaching definite conclusions about the effects of RF on human health.
... The effect of intermittent fasting (IF) on plasma lipid profile including triglycerides, total cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) are demonstrated by several recent studies (Ahmed, Farooq, & Siddiqi, 2021;Mirmiran, Bahadoran, Gaeini, Moslehi, & Azizi, 2019). Likewise, Akanji, Mojiminiyi, and Abdella (2000) reported that IF improves lipid parameters and reduces the risks of coronary heart disease in hyperlipidemic subjects, while . ...
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This research aimed to assess the effects of Ramadan intermittent fasting (RIF) on different dimensions, namely calorie intake, fullness and hunger sensations, mental health, body weight, waist circumference (WC), quality of sleep, body composition, hydration and nutritional status among female students at the University of Bahrain. A prospective single cohort study was conducted on 20 female students. The measurements were taken before Ramadan as well as the end of each week of Ramadan. From baseline to the end of Ramadan, there was a significant decrease in body weight (−0.779 kg, CI95% −1.287, −0.271), fat mass (FM) (−1.735 kg, CI95% −2.349, −1.122) and WC (−2.158 cm, CI95% −3.902, −0.414). In addition, the Hydragram® showed an increase at week 4 (0.288% CI95% 0.72, 0.504) and nutritional status with Nutrigram® increased during the time (Ptrend <0.001). No changes were detected for anxiety status, hunger and fullness sensations and quality of sleep. The decrease in weight positively affected the loss of FM (r = 0.597), and the increase in the Pittsburgh sleep quality index affected the reduction of FM (r= −0.460). The Ptrend<0.01 for visual analogue scales and WC showed a clear effect of time on these outcomes. The findings of this study suggest potential benefits of RIF on cardiovascular and metabolic health.
... significant reductions in APB, TG, TC, LDL-C, LDL-C/HDL-C ratio, TG/HDL-C ratio, and the atherogenic index, and significant increases in APA (P Z 0.001) and HDL-C (P Z 0.004) at the end of Ramadan fasting among fasting people [127]. Another semi-experimental quasi-randomized clinical trial found non-Ramadan IF (12 h/day over 6 weeks) among patients with sub-optimal HDL-C significantly reduced TC, TG, and LDL-C, and increased suboptimal HDL-C suggesting a cardioprotective effect and supporting IF as an effective strategy for CVD prevention and management [140]. The reported improvement in CMRF during Ramadan, especially lipid profile components, may partly be explained by reduced body weight in addition to dietary modifications in fat intake (total, saturated, and unsaturated). ...
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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=0.141, 95% CI: 0.053, 0.228); LDL-C (K=65, N=3354, Hedge’s g= −0.118, 95% CI: −0.201, 0.035); 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 the fasting people was the significant moderator for changes in both HDL-C (P=0.02) and VLDL-C (P=0.01), while male sex was the only significant moderator for changes in LDL-C (P=0.055). The fasting time duration was the only significant moderator for 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.
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Background The popularity of intermittent fasting (IF) has increased as more and more people are trying to avoid or alleviate obesity and metabolic disease. This study aimed to systematically explore the effects of various IF in humans. Methods The randomized controlled trials (RCTs) related to IF versus normal diet (non-intervention diet) or caloric restriction (CR) were retrieved in PubMed, Web of Science, the Cochrane Library database, and Embase. Extraction outcomes included, but not limited to, weight, body mass index (BMI), waist circumference (WC), glucose, and triglyceride (TG). Results Contrasting results showed that, participants had lower weight (WMD = 1.10, 95%CI: 0.09–2.12, p = 0.03) and BMI after IF (WMD = 0.38, 95%CI: 0.08–0.68, p = 0.01). The WC of participants in the IF group decreased significantly compared with the normal diet (WMD = 1.02, 95%CI: 0.06–1.99, p = 0.04). IF regulated fat mass (FM) more effectively than normal diet (WMD = 0.74, 95%CI: 0.17–1.31, p = 0.01). The fat-free mass of people after IF was higher (WMD=-0.73, 95%CI: (-1.45)-(-0.02), p = 0.05). There was no difference in blood glucose fluctuation between participants in the after IF and normal diet groups. The results of insulin and HOMA-IR, though, indicated that IF was significantly more beneficial than normal diet (SMD=-0.21, 95%CI: 0.02–0.40, p = 0.03, and WMD = 0.35, 95%CI: 0.04–0.65, p = 0.03, respectively). Cholesterol and TG levels after IF were also lower than after a normal diet (SMD = 0.22, 95%CI: 0.09–0.35, p = 0.001, and SMD = 0.13, 95%CI: 0.00-0.26, p = 0.05, respectively). Conclusion IF reduced weight, WC, and FM without affecting lean tissue. IF also could improve insulin resistance and blood lipid conditions compared with non-intervention diets.
Background Compared to other races/ethnicities, individuals from South Asia with obesity are strikingly susceptible to the presence of CVD risk factors and onset of CVD events – in part due to adiposopathic anatomic and metabolic responses to positive caloric balance. Pathogenic endocrine and immune effects of adipocyte hypertrophy and visceral fat accumulation both directly and indirectly promote among the most common metabolic diseases encountered in clinical practice – many being major cardiovascular disease (CVD) risk factors. This is especially applicable to those from South Asia – largely due to genetics, epigenetics, unhealthful nutrition, and physical inactivity. Methods This roundtable discussion included 4 obesity specialists engaged in the clinical management of obesity among patients of South Asian descent. Results Patients with obesity from South Asia have increased adipocyte size, fewer (functional) adipocytes, and increased visceral adiposity accompanied by functional endocrine and immune abnormalities. This helps explain the increased CVD risk factors and increased CVD risk among this unique population. These CVD risk factors include increased prevalence of metabolic syndrome (even at lower body mass index relative to other races), insulin resistance, type 2 diabetes mellitus, increased lipoprotein (a), and adiposopathic dyslipidemia [(i.e., elevated triglyceride levels, reduced high density lipoprotein cholesterol levels, increased low density lipoprotein (LDL) particle number, and increased prevalence of smaller and denser LDL particles]. Conclusion The four panelists of this roundtable discussion describe their practical diagnostic processes and treatment plans for patients from South Asia, with an emphasis on a patient-centered approach to obesity in this unique population.
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Intermittent fasting (IF) has been gaining popularity as a means of losing weight. The Ramadan fast (RF) is a form of IF practiced by millions of adult Muslims globally for a whole lunar month every year. It entails a major shift from normal eating patterns to exclusive nocturnal eating. RF is a state of intermittent liver glycogen depletion and repletion. The earlier (morning) part of the fasting day is marked by dominance of carbohydrate as the main fuel, but lipid becomes more important towards the afternoon and as the time for breaking the fast at sunset (iftar) gets closer. The practice of observing Ramadan fasting is accompanied by changes in sleeping and activity patterns, as well as circadian rhythms of hormones including cortisol, insulin, leptin, ghrelin, growth hormone, prolactin, sex hormones, and adiponectin. Few studies have investigated energy expenditure in the context of RF including resting metabolic rate (RMR) and total energy expenditure (TEE) and found no significant changes with RF. Changes in activity and sleeping patterns however do occur and are different from non-Ramadan days. Weight changes in the context of Ramadan fast are variable and typically modest with wise inter-individual variation. As well as its direct relevance to many religious observers, understanding intermittent fasting may have implications on weight loss strategies with even broader potential implications. This review examines current knowledge on different aspects of energy balance in RF, as a common model to learn from and also map out strategies for healthier outcomes in such settings.
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Intermittent fasting is a form of time restricted eating (typically 16 h fasting and 8 h eating), which has gained popularity in recent years and shows promise as a possible new paradigm in the approach to weight loss and the reduction of inflammation, and has many potential long term health benefits. In this review, the authors will incorporate many aspects of fasting, mainly focusing on its effects on the cardiovascular system, involving atherosclerosis progression, benefits for diabetes mellitus type 2, lowering of blood pressure, and exploring other cardiovascular risk factors (such as lipid profile and inflammation).
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High-density lipoprotein cholesterol (HDL-C) has been identified as a powerful independent negative predictor of cardiovascular disease. The beneficial effect of HDL is largely attributable to its key role in reverse cholesterol transport, whereby excess cholesterol in the peripheral tissues is transported to the liver, reducing the atherosclerotic burden. However, mounting evidence indicates that HDL also has pleiotropic properties, such as anti-inflammatory, anti-oxidative, and vasodilatory properties, which may contribute in reducing the incidence of heart failure. Actually, previous data from clinical and experimental studies have suggested that HDL exerts cardioprotective effects irrespective of the presence/absence of coronary artery disease. This review summarizes the currently available evidence regarding beneficial effects of HDL on the heart beyond its anti-atherogenic property. Understanding the mechanisms of cardiac protection by HDL will provide new insight into the underlying mechanism and therapeutic strategy for heart failure.
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Obesity is a worldwide epidemic due to the availability of many unhealthy food options and limited physical exercise. Restriction of the daily food intake results in weight loss, which is also associated with better health outcomes including triglycerides, total cholesterol, low-density lipoprotein cholesterol, blood pressure, glucose, insulin, and C-reactive protein. Our aim is to briefly discuss the effects of intermittent fasting on weight and other biochemical markers mentioned previously. The study is designed as a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. To assess the effectiveness of intermittent fasting, related studies were reviewed between 2000 and 2018 and 815 studies were identified. Only four articles met the preset inclusion and exclusion criteria. All four studies have shown a significant decrease in fat mass with P-values <0.01. It was also noted that some biochemical markers were significantly reduced such as the reduction in low-density lipoprotein and triglyceride with P-values < 0.05. Other biochemical markers had inconsistent results. Based on the qualitative analysis, intermittent fasting was found to be efficient in reducing weight, irrespective of the body mass index. Further studies are needed to assess the ability to maintain the lost weight without regaining it and the long-term effects of such dietary changes.
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Purpose of review: We review the underlying mechanisms and potential benefits of intermittent fasting (IF) from animal models and recent clinical trials. Recent findings: Numerous variations of IF exist, and study protocols vary greatly in their interpretations of this weight loss trend. Most human IF studies result in minimal weight loss and marginal improvements in metabolic biomarkers, though outcomes vary. Some animal models have found that IF reduces oxidative stress, improves cognition, and delays aging. Additionally, IF has anti-inflammatory effects, promotes autophagy, and benefits the gut microbiome. The benefit-to-harm ratio varies by model, IF protocol, age at initiation, and duration. We provide an integrated perspective on potential benefits of IF as well as key areas for future investigation. In clinical trials, caloric restriction and IF result in similar degrees of weight loss and improvement in insulin sensitivity. Although these data suggest that IF may be a promising weight loss method, IF trials have been of moderate sample size and limited duration. More rigorous research is needed.
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Intermittent fasting, whose proposed benefits include the improvement of lipid profile and the body weight loss, has gained considerable scientific and popular repercussion. This review aimed to consolidate studies that analyzed the lipid profile in humans before and after intermittent fasting period through a detailed review; and to propose the physiological mechanism, considering the diet and the body weight loss. Normocaloric and hypocaloric intermittent fasting may be a dietary method to aid in the improvement of the lipid profile in healthy, obese and dyslipidemic men and women by reducing total cholesterol, LDL, triglycerides and increasing HDL levels. However, the majority of studies that analyze the intermittent fasting impacts on the lipid profile and body weight loss are observational based on Ramadan fasting, which lacks large sample and detailed information about diet. Randomized clinical trials with a larger sample size are needed to evaluate the IF effects mainly in patients with dyslipidemia.
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Introduction The potential impact of targeting different components of an adverse lipid profile in populations with multiple cardiovascular risk factors is not completely clear. This study aims to assess the association between different components of the standard lipid profile with all-cause mortality and hospitalization due to cardiovascular events in a high-risk population. Methods This prospective registry included high risk adults over 30 years old free of cardiovascular disease (2008–2012). Diagnosis of hypertension, dyslipidemia or diabetes mellitus was inclusion criterion. Lipid biomarkers were evaluated. Primary endpoints were all-cause mortality and hospital admission due to coronary heart disease or stroke. We estimated adjusted rate ratios (aRR), absolute risk differences and population attributable risk associated with adverse lipid profiles. Results 51,462 subjects were included with a mean age of 62.6 years (47.6% men). During an average follow-up of 3.2 years, 919 deaths, 1666 hospitalizations for coronary heart disease and 1510 hospitalizations for stroke were recorded. The parameters that showed an increased rate for total mortality, coronary heart disease and stroke hospitalization were, respectively, low HDL-Cholesterol: aRR 1.25, 1.29 and 1.23; high Total/HDL-Cholesterol: aRR 1.22, 1.38 and 1.25; and high Triglycerides/HDL-Cholesterol: aRR 1.21, 1.30, 1.09. The parameters that showed highest population attributable risk (%) were, respectively, low HDL-Cholesterol: 7.70, 11.42, 8.40; high Total/HDL-Cholesterol: 6.55, 12.47, 8.73; and high Triglycerides/HDL-Cholesterol: 8.94, 15.09, 6.92. Conclusions In a population with cardiovascular risk factors, HDL-cholesterol, Total/HDL-cholesterol and triglycerides/HDL-cholesterol ratios were associated with a higher population attributable risk for cardiovascular disease compared to other common biomarkers.
Evidence is accumulating that eating in a 6-hour period and fasting for 18 hours can trigger a metabolic switch from glucose-based to ketone-based energy, with increased stress resistance, increased longevity, and a decreased incidence of diseases, including cancer and obesity.
Objective: Objective: Intermittent fasting (IF) is a term used to describe a variety of eating patterns in which no or few calories are consumed for time periods that can range from 12 hours to several days, on a recurring basis. This review is focused on the physiological responses of major organ systems, including the musculoskeletal system, to the onset of the metabolic switch: the point of negative energy balance at which liver glycogen stores are depleted and fatty acids are mobilized (typically beyond 12 hours after cessation of food intake). Results and conclusions: Emerging findings suggest that the metabolic switch from glucose to fatty acid-derived ketones represents an evolutionarily conserved trigger point that shifts metabolism from lipid/cholesterol synthesis and fat storage to mobilization of fat through fatty acid oxidation and fatty acid-derived ketones, which serve to preserve muscle mass and function. Thus, IF regimens that induce the metabolic switch have the potential to improve body composition in overweight individuals. Moreover, IF regimens also induce the coordinated activation of signaling pathways that optimize physiological function, enhance performance, and slow aging and disease processes. Future randomized controlled IF trials should use biomarkers of the metabolic switch (e.g., plasma ketone levels) as a measure of compliance and of the magnitude of negative energy balance during the fasting period.
Importance: Alternate-day fasting has become increasingly popular, yet, to date, no long-term randomized clinical trials have evaluated its efficacy. Objective: To compare the effects of alternate-day fasting vs daily calorie restriction on weight loss, weight maintenance, and risk indicators for cardiovascular disease. Design, setting, and participants: A single-center randomized clinical trial of obese adults (18 to 64 years of age; mean body mass index, 34) was conducted between October 1, 2011, and January 15, 2015, at an academic institution in Chicago, Illinois. Interventions: Participants were randomized to 1 of 3 groups for 1 year: alternate-day fasting (25% of energy needs on fast days; 125% of energy needs on alternating "feast days"), calorie restriction (75% of energy needs every day), or a no-intervention control. The trial involved a 6-month weight-loss phase followed by a 6-month weight-maintenance phase. Main outcomes and measures: The primary outcome was change in body weight. Secondary outcomes were adherence to the dietary intervention and risk indicators for cardiovascular disease. Results: Among the 100 participants (86 women and 14 men; mean [SD] age, 44 [11] years), the dropout rate was highest in the alternate-day fasting group (13 of 34 [38%]), vs the daily calorie restriction group (10 of 35 [29%]) and control group (8 of 31 [26%]). Mean weight loss was similar for participants in the alternate-day fasting group and those in the daily calorie restriction group at month 6 (-6.8% [95% CI, -9.1% to -4.5%] vs -6.8% [95% CI, -9.1% to -4.6%]) and month 12 (-6.0% [95% CI, -8.5% to -3.6%] vs -5.3% [95% CI, -7.6% to -3.0%]) relative to those in the control group. Participants in the alternate-day fasting group ate more than prescribed on fast days, and less than prescribed on feast days, while those in the daily calorie restriction group generally met their prescribed energy goals. There were no significant differences between the intervention groups in blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, insulin resistance, C-reactive protein, or homocysteine concentrations at month 6 or 12. Mean high-density lipoprotein cholesterol levels at month 6 significantly increased among the participants in the alternate-day fasting group (6.2 mg/dL [95% CI, 0.1-12.4 mg/dL]), but not at month 12 (1.0 mg/dL [95% CI, -5.9 to 7.8 mg/dL]), relative to those in the daily calorie restriction group. Mean low-density lipoprotein cholesterol levels were significantly elevated by month 12 among the participants in the alternate-day fasting group (11.5 mg/dL [95% CI, 1.9-21.1 mg/dL]) compared with those in the daily calorie restriction group. Conclusions and relevance: Alternate-day fasting did not produce superior adherence, weight loss, weight maintenance, or cardioprotection vs daily calorie restriction. Trial registration: Identifier: NCT00960505.