Intermittent Fasting, Insufficient Sleep, and Circadian Rhythm: Interaction and Effects on the Cardiometabolic System
Purpose of Review
Sleep, circadian rhythms, and fasting/feeding are important factors that affect cardiometabolic function. Here, we review recent studies that assessed the role of intermittent fasting, short sleep duration, and circadian rhythm disruption, as well as their interactions, on the risk of cardiometabolic dysfunction.
The cardiometabolic system is sensitive to sleep, circadian rhythms, and fasting/feeding patterns. Recent data show that these factors may influence each other and hence, directly or indirectly affect cardiometabolic risk. Fasting/feeding schedules and mealtimes may cause misalignment of the circadian system resulting in several cardiometabolic disturbances. Recent data reveal that intermittent fasting (IF) improves several cardiometabolic indicators in both laboratory animals and humans maintained on IF diets during alternate day fasting, diurnal IF, or time-restricted feeding. However, most of the human studies recruited a modest number of participants and did not control for several confounding factors that may have affected the measurement of cardiometabolic parameters, such as sleep duration and timing, energy expenditure, and light exposure.
Current evidence shows that IF, sleep, and circadian rhythms can affect cardiometabolic risk both individually or collectively. IF, adequate sleep, and matching mealtimes with the circadian clock improve several cardiometabolic parameters. More extensive human studies that assess the interaction between the three factors in the general population are needed to complement the currently available short-term laboratory-based human studies.
KeywordsDiurnal fasting Sleep Biological clock Cardiometabolic disease Time restricted feeding Ramadan
The authors thank the Deanship of Scientific Research and RSSU at King Saud University for their technical support.
This work was supported by the Strategic Technologies Program of the National Plan for Sciences and Technology and Innovation in the Kingdom of Saudi Arabia (MED511-02-08).
Compliance with Ethical Standards
Conflict of Interest
Aljohara S. Almeneessier declares no conflicts of interest.
Ahmed S. BaHammam declares no conflicts of interest.
Seithikurippu R. Pandi-Perumal declares no conflict of interest. Pandi-Perumal is the President and Chief Executive Officer of Somnogen Canada Inc. Pandi-Perumal has edited several academic volumes for which he will receive annual royalties.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
- 4.•• Qasrawi SO, Pandi-Perumal SR, BaHammam AS. The effect of intermittent fasting during Ramadan on sleep, sleepiness, cognitive function, and circadian rhythm. Sleep Breath. 2017;21(3):577–86. https://doi.org/10.1007/s11325-017-1473-x. This is a recent review that provides details on the relation between diurnal intermittent fasting and sleep, cognitive function, and circadian rhythm. PubMedGoogle Scholar
- 5.Chattu VK, Sakhamuri SM, Kumar R, Spence DW, BaHammam AS, Pandi-Perumal SR. Insufficient sleep: is it time to classify it as a noncommunicable disease? Sleep Sci. 2018; (in press)Google Scholar
- 10.National Sleep Foundation. Sleep in America poll. In: Sleep health index 2014—highlights. National Sleep Foudation, Washington, DC. 2014. https://sleepfoundation.org/sleep-health-index-2014-highlights. Accessed 6 Apr 2018.
- 11.Liu Y, Wheaton AG, Chapman DP, Cunningham TJ, Lu H, Croft JB. Prevalence of healthy sleep duration among adults—United States. MMWR Morb Mortal Wkly Rep. 2014;65(6):137–41.Google Scholar
- 14.•• Miller MA, Kruisbrink M, Wallace J, Ji C, Cappuccio FP. Sleep duration and incidence of obesity in infants, children and adolescents: a systematic review and meta-analysis of prospective studies. Sleep. 2018;41(4) https://doi.org/10.1093/sleep/zsy018. A systematic analysis of 42 prospective studies that assessed the relationship between sleep and obesity in a pediatric population. It showed that short sleep duration is a risk factor for the development of obesity in infants, children, and adolescents.
- 15.• Wu Y, Gong Q, Zou Z, Li H, Zhang X. Short sleep duration and obesity among children: a systematic review and meta-analysis of prospective studies. Obes Res Clin Pract. 2017;11(2):140–50. https://doi.org/10.1016/j.orcp.2016.05.005. A systematic review and meta-analysis of prospective studies that assessed the relationship between short sleep duration and obesity among children. It provided evidence that short sleep duration in children is associated with a significantly increased risk of obesity. PubMedGoogle Scholar
- 16.•• Li L, Zhang S, Huang Y, Chen K. Sleep duration and obesity in children: a systematic review and meta-analysis of prospective cohort studies. J Paediatr Child Health. 2017;53(4):378–85. https://doi.org/10.1111/jpc.13434. A systematic review and meta-analysis of prospective cohort studies. Short sleep duration increased the risk of childhood obesity. PubMedGoogle Scholar
- 18.• Fatima Y, Doi SA, Mamun AA. Longitudinal impact of sleep on overweight and obesity in children and adolescents: a systematic review and bias-adjusted meta-analysis. Obes Rev. 2015;16(2):137–49. https://doi.org/10.1111/obr.12245. A systematic review and meta-analysis that explored the prospective association between short sleep and overweight/obesity in young subjects. It showed that short sleep duration in young subjects is significantly associated with future overweight/obesity. PubMedGoogle Scholar
- 19.• Xi B, He D, Zhang M, Xue J, Zhou D. Short sleep duration predicts risk of metabolic syndrome: a systematic review and meta-analysis. Sleep Med Rev. 2014;18(4):293–7. https://doi.org/10.1016/j.smrv.2013.06.001. A systematic review and meta-analysis that assessed the association between sleep duration and metabolic syndrome. Short rather than long sleep duration was significantly associated with risk of metabolic syndrome. PubMedGoogle Scholar
- 20.• Shan Z, Ma H, Xie M, Yan P, Guo Y, Bao W, et al. Sleep duration and risk of type 2 diabetes: a meta-analysis of prospective studies. Diabetes Care. 2015;38(3):529–37. https://doi.org/10.2337/dc14-2073. A systematic review and a meta-analysis of 10 prospective studies that assessed the association between sleep duration and type 2 diabetes. It revealed that both short and long sleep duration are associated with a significantly increased risk of type 2 diabetes. PubMedGoogle Scholar
- 21.•• Anothaisintawee T, Reutrakul S, Van Cauter E, Thakkinstian A. Sleep disturbances compared to traditional risk factors for diabetes development: systematic review and meta-analysis. Sleep Med Rev. 2016;30:11–24. https://doi.org/10.1016/j.smrv.2015.10.002. A systematic review and meta-analysis that compared the risk associated with sleep disturbances to traditional risk factors (i.e., overweight, family history, and physical inactivity) for diabetes development. It demonstrated that the risk of developing diabetes associated with sleep disturbances is comparable to thatof traditional risk factors. PubMedGoogle Scholar
- 22.•• Wang Y, Mei H, Jiang YR, Sun WQ, Song YJ, Liu SJ, et al. Relationship between duration of sleep and hypertension in adults: a meta-analysis. J Clin Sleep Med. 2015;11(9):1047–56. https://doi.org/10.5664/jcsm.5024.. A meta-analysis that assessed the association between excessively longer and shorter periods of sleep and high blood pressure. Both excessively longer and shorter periods of sleep may be risk factors for high blood pressure. PubMedPubMedCentralGoogle Scholar
- 23.• Meng L, Zheng Y, Hui R. The relationship of sleep duration and insomnia to risk of hypertension incidence: a meta-analysis of prospective cohort studies. Hypertens Res. 2013;36(11):985–95. https://doi.org/10.1038/hr.2013.70. A meta-analysis of prospective cohort studies that assessed the relationship between sleep duration and risk of hypertension incidence. It showed that short sleep duration is associated with hypertension incidence. PubMedPubMedCentralGoogle Scholar
- 24.• Guo X, Zheng L, Wang J, Zhang X, Li J, Sun Y. Epidemiological evidence for the link between sleep duration and high blood pressure: a systematic review and meta-analysis. Sleep Med. 2013;14(4):324–32. https://doi.org/10.1016/j.sleep.2012.12.001. A systematic review and meta-analysis of epidemiological evidence for the link between sleep duration and high blood pressure. It showed that Short sleep duration was associated with a higher risk for hypertension. PubMedGoogle Scholar
- 25.• Wang D, Li W, Cui X, Meng Y, Zhou M, Xiao L, et al. Sleep duration and risk of coronary heart disease: a systematic review and meta-analysis of prospective cohort studies. Int J Cardiol. 2016;219:231–9. https://doi.org/10.1016/j.ijcard.2016.06.027. A systematic review and meta-analysis of prospective cohort studies that assessed the association between sleep duration and risk of coronary heart disease. It showed that both short and long sleep durations are significantly associated with increased risk of coronary heart disease. PubMedGoogle Scholar
- 26.• He Q, Sun H, Wu X, Zhang P, Dai H, Ai C, et al. Sleep duration and risk of stroke: a dose-response meta-analysis of prospective cohort studies. Sleep Med. 2017;32:66–74. https://doi.org/10.1016/j.sleep.2016.12.012. A meta-analysis of prospective cohort studies that assessed the association between sleep duration and stroke. PubMedGoogle Scholar
- 27.• Li W, Wang D, Cao S, Yin X, Gong Y, Gan Y, et al. Sleep duration and risk of stroke events and stroke mortality: a systematic review and meta-analysis of prospective cohort studies. Int J Cardiol. 2016;223:870–6. https://doi.org/10.1016/j.ijcard.2016.08.302. A systematic review and meta-analysis of prospective cohort studies that assessed the association between sleep duration and risk of stroke events and stroke mortality. It showed that both short and long duration of sleep are predictors of stroke outcomes. PubMedGoogle Scholar
- 28.• Itani O, Jike M, Watanabe N, Kaneita Y. Short sleep duration and health outcomes: a systematic review, meta-analysis, and meta-regression. Sleep Med. 2017;32:246–56. https://doi.org/10.1016/j.sleep.2016.08.006. A systematic review and meta-regression of prospective cohort studies with follow-ups of one year or more on associations between short sleep duration and the outcomes. It revealed a linear association between a statistically significant increase in mortality and sleep duration at less than six hours. PubMedGoogle Scholar
- 29.• Yin J, Jin X, Shan Z, Li S, Huang H, Li P, et al. Relationship of sleep duration with all-cause mortality and cardiovascular events: a systematic review and dose-response meta-analysis of prospective cohort studies. J Am Heart Assoc. 2017;6(9):e005947. https://doi.org/10.1161/JAHA.117.005947. A systematic review and dose-response meta-analysis of prospective cohort studies that assessed the relationship of sleep duration with all-cause mortality and cardiovascular events. The findings indicated that both short and long sleep duration is associated with an increased risk of all-cause mortality and cardiovascular events. PubMedPubMedCentralGoogle Scholar
- 30.• Irwin MR, Olmstead R, Carroll JE. Sleep disturbance, sleep duration, and inflammation: a systematic review and meta-analysis of cohort studies and experimental sleep deprivation. Biol Psychiatry. 2016;80(1):40–52. https://doi.org/10.1016/j.biopsych.2015.05.014. A systematic review and meta-analysis of the association between sleep disturbance, sleep duration, and inflammation, which showed that sleep disturbance and long sleep duration, but not short sleep duration, are associated with increases in markers of systemic inflammation. PubMedGoogle Scholar
- 34.Magriplis E, Farajian P, Panagiotakos DB, Risvas G, Zampelas A. The relationship between behavioral factors, weight status and a dietary pattern in primary school aged children: the GRECO study. Clin Nutr. 2018; https://doi.org/10.1016/j.clnu.2018.01.015.
- 35.Wolf C, Wolf S, Weiss M, Nino G. Children’s environmental health in the digital era: understanding early screen exposure as a preventable risk factor for obesity and sleep disorders. Children (Basel). 2018;5(2) https://doi.org/10.3390/children5020031.
- 36.• Aldabal L, Bahammam AS. Metabolic, endocrine, and immune consequences of sleep deprivation. Open Respir Med J. 2011;5:31–43. https://doi.org/10.2174/1874306401105010031. A comprehensive review of the results of experimental and epidemiological studies that examined the relationship between sleep duration and the immune and endocrine systems. PubMedPubMedCentralGoogle Scholar
- 37.•• St-Onge MP, Ard J, Baskin ML, Chiuve SE, Johnson HM, Kris-Etherton P, et al. Meal timing and frequency: implications for cardiovascular disease prevention: a scientific statement from the American Heart Association. Circulation. 2017;135(9):e96–e121. https://doi.org/10.1161/CIR.0000000000000476. A Scientific Statement from the American Heart Association that discusses in depth the effects of meal timing and frequency on cardiometabolic health markers, namely obesity, lipid profile, insulin resistance, and blood pressure. PubMedGoogle Scholar
- 40.Broussard JL, Ehrmann DA, Van Cauter E, Tasali E, Brady MJ. Impaired insulin signaling in human adipocytes after experimental sleep restriction: a randomized, crossover study. Ann Intern Med. 2012;157(8):549–57. https://doi.org/10.7326/0003-4819-157-8-201210160-00005.PubMedPubMedCentralGoogle Scholar
- 42.Biaggioni I. Circadian clocks, autonomic rhythms, and blood pressure dipping. Hypertension. 2008;52(5):797–8. https://doi.org/10.1161/HYPERTENSIONAHA.108.117234.PubMedPubMedCentralGoogle Scholar
- 44.• Haack M, Serrador J, Cohen D, Simpson N, Meier-Ewert H, Mullington JM. Increasing sleep duration to lower beat-to-beat blood pressure: a pilot study. J Sleep Res. 2013;22(3):295–304. https://doi.org/10.1111/jsr.12011. A pilot study of a small sample revealed that sleep extension significantly decreased systolic and diastolic beat-to-beat blood pressure averaged across the 24-h. PubMedGoogle Scholar
- 45.•• Lao XQ, Liu X, Deng HB, Chan TC, Ho KF, Wang F, et al. Sleep quality, sleep duration, and the risk of coronary heart disease: a prospective cohort study with 60,586 adults. J Clin Sleep Med. 2018;14(1):109–17. https://doi.org/10.5664/jcsm.6894. A recent large prospective cohort study that assessed the joint effects of sleep quality and sleep duration on the development of coronary heart disease. PubMedPubMedCentralGoogle Scholar
- 46.•• Svensson AK, Svensson T, Kitlinski M, Almgren P, Engstrom G, Nilsson PM, et al. Incident diabetes mellitus may explain the association between sleep duration and incident coronary heart disease. Diabetologia. 2018;61(2):331–41. https://doi.org/10.1007/s00125-017-4464-3. A recent large study that assessed the relationship between sleep duration incident diabetes mellitus and incident coronary artery disease. PubMedGoogle Scholar
- 47.•• Strand LB, Tsai MK, Gunnell D, Janszky I, Wen CP, Chang SS. Self-reported sleep duration and coronary heart disease mortality: a large cohort study of 400,000 Taiwanese adults. Int J Cardiol. 2016;207:246–51. https://doi.org/10.1016/j.ijcard.2016.01.044. A large prospective study that prospectively examined the associations of sleep duration with CHD while accounting for several cardiovascular risk factors and chronic diseases. PubMedGoogle Scholar
- 48.• Fang J, Wheaton AG, Ayala C. Sleep duration and history of stroke among adults from the USA. J Sleep Res. 2014;23(5):531–7. https://doi.org/10.1111/jsr.12160. A study that assessed the association between self-reported sleep duration and prevalence of stroke in a large sample using the National Health Interview Surveys. There was an association of short sleep duration with stroke, and as association of long sleep duration with stroke, particularly among indivuals aged 65 years or older. PubMedPubMedCentralGoogle Scholar
- 51.• Reutrakul S, Knutson KL. Consequences of circadian disruption on cardiometabolic health. Sleep Med Clin. 2015;10(4):455–68. https://doi.org/10.1016/j.jsmc.2015.07.005. A comprehensive review of cardiometabolic health of shift work, and potential mediators linking chronotype and shift work to circadian disruption and cardiometabolic health. PubMedPubMedCentralGoogle Scholar
- 53.• Nagata C, Tamura T, Wada K, Konishi K, Goto Y, Nagao Y, et al. Sleep duration, nightshift work, and the timing of meals and urinary levels of 8-isoprostane and 6-sulfatoxymelatonin in Japanese women. Chronobiol Int. 2017;34(9):1187–96. https://doi.org/10.1080/07420528.2017.1355313. A study that examined the association of sleeping habits, nightshift work, and the timing of meals with urinary levels of 8-isoprostane, a marker of oxidative stress, and 6-sulfatoxymelatonin, the principal metabolite of melatonin. PubMedGoogle Scholar
- 54.• Wang F, Zhang L, Zhang Y, Zhang B, He Y, Xie S, et al. Meta-analysis on night shift work and risk of metabolic syndrome. Obes Rev. 2014;15(9):709–20. https://doi.org/10.1111/obr.12194.. This meta-analysis suggested that night shift work is significantly associated with the risk of metabolic syndrome. PubMedGoogle Scholar
- 57.• Leproult R, Holmback U, Van Cauter E. Circadian misalignment augments markers of insulin resistance and inflammation, independently of sleep loss. Diabetes. 2014;63(6):1860–9. https://doi.org/10.2337/db13-1546. This study assessed the effect of misalignment of circadian rhythms in shift workers on the metabolic system. It reported that circadian misalignment in shift work may increase diabetes risk and inflammation, independently of sleep loss. PubMedPubMedCentralGoogle Scholar
- 59.Patterson RE, Sears DD. Metabolic effects of intermittent fasting. Annu Rev Nutr. 2017;37:371–93. https://doi.org/10.1146/annurev-nutr-071816-064634.PubMedGoogle Scholar
- 60.Anson RM, Guo Z, de Cabo R, Iyun T, Rios M, Hagepanos A, et al. Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from calorie intake. Proc Natl Acad Sci U S A. 2003;100(10):6216–20. https://doi.org/10.1073/pnas.1035720100.PubMedPubMedCentralGoogle Scholar
- 62.Harvie MN, Pegington M, Mattson MP, Frystyk J, Dillon B, Evans G, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomized trial in young overweight women. Int J Obes. 2011;35(5):714–27. https://doi.org/10.1038/ijo.2010.171.Google Scholar
- 64.• Eshghinia S, Mohammadzadeh F. The effects of modified alternate-day fasting diet on weight loss and CAD risk factors in overweight and obese women. J Diabetes Metab Disord. 2013;12(1):4. https://doi.org/10.1186/2251-6581-12-4. This study assessed the ability of modified alternate-day fasting (ADF) to enhance weight loss and lower cardiovascular risk factors in overweight and obese women. The findings showed that short time ADF helped obese individuals lose weight and decrease some coronary artery disease risk factors. PubMedPubMedCentralGoogle Scholar
- 69.Johnson JB, Summer W, Cutler RG, Martin B, Hyun DH, Dixit VD, et al. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma. Free Radic Biol Med. 2007;42(5):665–74. https://doi.org/10.1016/j.freeradbiomed.2006.12.005.PubMedGoogle Scholar
- 71.• Hatori M, Vollmers C, Zarrinpar A, DiTacchio L, Bushong EA, Gill S, et al. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 2012;15(6):848–60. https://doi.org/10.1016/j.cmet.2012.04.019. This study tested test whether obesity and metabolic diseases result from high-fat diet or disruption of metabolic cycles in mice. PubMedPubMedCentralGoogle Scholar
- 72.Sequea DA, Sharma N, Arias EB, Cartee GD. Calorie restriction enhances insulin-stimulated glucose uptake and Akt phosphorylation in both fast-twitch and slow-twitch skeletal muscle of 24-month-old rats. J Gerontol A Biol Sci Med Sci. 2012;67(12):1279–85. https://doi.org/10.1093/gerona/gls085.PubMedPubMedCentralGoogle Scholar
- 76.• Godar RJ, Ma X, Liu H, Murphy JT, Weinheimer CJ, Kovacs A, et al. Repetitive stimulation of autophagy-lysosome machinery by intermittent fasting preconditions the myocardium to ischemia-reperfusion injury. Autophagy. 2015;11(9):1537–60. https://doi.org/10.1080/15548627.2015.1063768. This study examined the effects of intermittent fasting on myocardial ischemia-reperfusion injury via transcriptional stimulation of the autophagy-lysosome machinery. PubMedPubMedCentralGoogle Scholar
- 79.Mindikoglu AL, Opekun AR, Gagan SK, Devaraj S. Impact of time-restricted feeding and dawn-to-sunset fasting on circadian rhythm, obesity, metabolic syndrome, and nonalcoholic fatty liver disease. Gastroenterol Res Pract. 2017;2017:3932491. https://doi.org/10.1155/2017/3932491.PubMedPubMedCentralGoogle Scholar
- 81.• Oosterman JE, Kalsbeek A, la Fleur SE, Belsham DD. Impact of nutrients on circadian rhythmicity. Am J Physiol Regul Integr Comp Physiol. 2015;308(5):R337–50. https://doi.org/10.1152/ajpregu.00322.2014. A comprehensive review that discusses the influence of nutrients, in particular fatty acids and glucose, on behavioral and molecular circadian rhythms. PubMedGoogle Scholar
- 89.Bahammam. Effect of fasting during Ramadan on sleep architecture, daytime sleepiness and sleep pattern. Sleep Biol Rhythm. 2004;2:135–43.Google Scholar
- 90.• BaHammam A, Alrajeh M, Albabtain M, Bahammam S, Sharif M. Circadian pattern of sleep, energy expenditure, and body temperature of young healthy men during the intermittent fasting of Ramadan. Appetite. 2010;54(2):426–9. https://doi.org/10.1016/j.appet.2010.01.011. This study that examined the effects of lifestyle changes during Ramadan on individuals in an unconstrained environment who have delayed sleep phase syndrome. The results showed that in addition to sudden shift in meal times, other factors may affect the sleep pattern and circadian rhythms during Ramadan. PubMedGoogle Scholar
- 92.•• Almeneessier AS, Bahammam AS, Sharif MM, Bahammam SA, Nashwan SZ, Pandi Perumal SR, et al. The influence of intermittent fasting on the circadian pattern of melatonin while controlling for caloric intake, energy expenditure, light exposure, and sleep schedules: a preliminary report. Ann Thorac Med. 2017;12(3):183–90. https://doi.org/10.4103/atm.ATM_15_17. A recent experimental study that assessed the effects of diurnal intermittent fasting on the circadian pattern of melatonin secretion while controlling for meal composition, caloric intake, energy expenditure, sleep schedule and duration and light exposure. PubMedPubMedCentralGoogle Scholar
- 93.• Alzoghaibi MA, Pandi-Perumal SR, Sharif MM, BaHammam AS. Diurnal intermittent fasting during Ramadan: the effects on leptin and ghrelin levels. PLoS One. 2014;9(3):e92214. https://doi.org/10.1371/journal.pone.0092214. This study assessed the effect of Ramadan diurnal intermittent fasting, on plasma levels of leptin and ghrelin while controlling for several potential confounding variables. PubMedPubMedCentralGoogle Scholar
- 94.Bahammam. Sleep pattern, daytime sleepiness, and eating habits during the month of Ramadan. Sleep Hypnosis. 2003;5:165–74.Google Scholar
- 98.• Bahammam AS, Alaseem AM, Alzakri AA, Sharif MM. The effects of Ramadan fasting on sleep patterns and daytime sleepiness: an objective assessment. J Res Med Sci. 2013;18(2):127–31. This study objectively examined the effects of Ramadan fasting on patterns of sleep and daytime sleepiness in the unconstrained environment. The results showed a shift delay in circadian rhythm but there was no objective evidence for increased sleepiness during fasting. PubMedPubMedCentralGoogle Scholar
- 100.•• Bahammam AS, Almushailhi K, Pandi-Perumal SR, Sharif MM. Intermittent fasting during Ramadan: does it affect sleep? J Sleep Res. 2014;23(1):35–43. https://doi.org/10.1111/jsr.12076. An experimental study that evaluated the effects of diurnal intermittent fasting on sleep architecture while controlling for meal composition, caloric intake, energy expenditure and light exposure. PubMedGoogle Scholar
- 102.Kotrbacek V, Schweigel M, Honig Z. The effect of short-term fasting on sleep in pigs. Vet Med (Praha). 1990;35(9):547–52.Google Scholar
- 103.•• Sadeghirad B, Motaghipisheh S, Kolahdooz F, Zahedi MJ, Haghdoost AA. Islamic fasting and weight loss: a systematic review and meta-analysis. Public Health Nutr. 2014;17(2):396–406. https://doi.org/10.1017/S1368980012005046. A systematic review and meta-analysis that reviewed studies that examined the effects of Islamic diurnal intermittent fasting on weight loss. PubMedGoogle Scholar
- 104.•• Kul S, Savas E, Ozturk ZA, Karadag G. Does Ramadan fasting alter body weight and blood lipids and fasting blood glucose in a healthy population? A meta-analysis. J Relig Health. 2014;53(3):929–42. https://doi.org/10.1007/s10943-013-9687-0. A systematic review and meta-analysis of studies that investigated the effects of Ramadan diurnal intermittent fasting on body weight, blood lipids and fasting blood glucose in a healthy population. PubMedGoogle Scholar
- 105.• Yeoh EC, Zainudin SB, Loh WN, Chua CL, Fun S, Subramaniam T, et al. Fasting during Ramadan and associated changes in glycaemia, caloric intake and body composition with gender differences in Singapore. Ann Acad Med Singap. 2015;44(6):202–6. This study examined the changes in body composition and metabolic profile in fast performers during Ramadan. PubMedGoogle Scholar
- 106.• Unalacak M, Kara IH, Baltaci D, Erdem O, Bucaktepe PG. Effects of Ramadan fasting on biochemical and hematological parameters and cytokines in healthy and obese individuals. Metab Syndr Relat Disord. 2011;9(2):157–61. https://doi.org/10.1089/met.2010.0084. This study investigated the effects of Ramadan fasting on biochemical and hematological parameters and cytokines in healthy and obese individuals. It showed that Ramadan fasting has beneficial influences on the inflammatory state. PubMedGoogle Scholar
- 107.• Al-Shafei AI. Ramadan fasting ameliorates arterial pulse pressure and lipid profile, and alleviates oxidative stress in hypertensive patients. Blood Press. 2014;23(3):160–7. https://doi.org/10.3109/08037051.2013.836808. This study assessed the effects on arterial pulse pressure (PP), lipid profile and oxidative stress were characterized in hypertensives. Fasting improved PP and lipids profile and ameliorates oxidative stress. PubMedGoogle Scholar
- 109.Held C, White HD, Stewart RAH, Budaj A, Cannon CP, Hochman JS, et al. Inflammatory biomarkers interleukin-6 and C-reactive protein and outcomes in stable coronary heart disease: experiences from the STABILITY (Stabilization of Atherosclerotic Plaque by Initiation of Darapladib Therapy) Trial. J Am Heart Assoc. 2017;6(10):e005077. https://doi.org/10.1161/JAHA.116.005077.PubMedPubMedCentralGoogle Scholar
- 110.Srikanthan K, Feyh A, Visweshwar H, Shapiro JI, Sodhi K. Systematic review of metabolic syndrome biomarkers: a panel for early detection, management, and risk stratification in the West Virginian population. Int J Med Sci. 2016;13(1):25–38. https://doi.org/10.7150/ijms.13800.PubMedPubMedCentralGoogle Scholar
- 111.• Shariatpanahi MV, Shariatpanahi ZV, Shahbazi S, Moshtaqi M. Effect of fasting with two meals on BMI and inflammatory markers of metabolic syndrome. Pak J Biol Sci. 2012;15(5):255–8. This study examined the effect of fasting with two meals on BMI and inflammatory markers ofmetabolic syndrome. PubMedGoogle Scholar
- 112.Tanigaki K, Vongpatanasin W, Barrera JA, Atochin DN, Huang PL, Bonvini E, et al. C-reactive protein causes insulin resistance in mice through Fcgamma receptor IIB-mediated inhibition of skeletal muscle glucose delivery. Diabetes. 2013;62(3):721–31. https://doi.org/10.2337/db12-0133.PubMedPubMedCentralGoogle Scholar
- 113.• Faris MA, Kacimi S, Al-Kurd RA, Fararjeh MA, Bustanji YK, Mohammad MK, et al. Intermittent fasting during Ramadan attenuates proinflammatory cytokines and immune cells in healthy subjects. Nutr Res. 2012;32(12):947–55. https://doi.org/10.1016/j.nutres.2012.06.021. A cross-sectional study investigated the effect of Ramadan diurnal fasting on selected inflammatory cytokines and immune biomarkers in healthy subjects in an unconstrained environment. PubMedGoogle Scholar
- 115.Buxton OM, Broussard JL, Zahl AK, Hall M. Effects of sleep deficiency on hormones, cytokines, and metabolism. In: Redline S, Berger RA, editors. Impact of sleep and sleep disturbances on obesity and cancer, energy balance and cancer. New York: Springer Science+Business Media; 2014. p. 25–50.Google Scholar
- 118.• Faris MA, Hussein RN, Al-Kurd RA, Al-Fararjeh MA, Bustanji YK, Mohammad MK. Impact of Ramadan intermittent fasting on oxidative stress measured by urinary 15-f(2t)-isoprostane. J Nutr Metab. 2012;2012:802924. https://doi.org/10.1155/2012/802924. This study investigated the effect of Ramadan fasting on oxidative stress in healthy individuals in an unconstrained environment. PubMedPubMedCentralGoogle Scholar
- 121.• Al-Shafei AI. Ramadan fasting ameliorates oxidative stress and improves glycemic control and lipid profile in diabetic patients. Eur J Nutr. 2014;53:1475–81. https://doi.org/10.1007/s00394-014-0650-y. This study investigated the effect of Ramadan fasting on oxidative stress in patients with diabetes in an unconstrained environment. PubMedGoogle Scholar
- 122.• BaHammam AS, Pandi-Perumal SR, Alzoghaibi MA. The effect of Ramadan intermittent fasting on lipid peroxidation in healthy young men while controlling for diet and sleep: a pilot study. Ann Thorac Med. 2016;11(1):43–8. https://doi.org/10.4103/1817-1737.172296. This study examined the effect of diurnal intermittent during and outside of Ramadan on the circadian changes in lipid peroxidation marker malondialdehyde during and outside while controlling for potential confounders. PubMedPubMedCentralGoogle Scholar