Modified alternate-day fasting vs. calorie restriction in the treatment of patients with metabolic syndrome: A randomized clinical trial
Introduction
Metabolic syndrome (MetS) is a highly prevalent metabolic disorder which is defied by a set of several interrelated cardiometabolic risk factors, such as abdominal obesity, insulin resistance, hyperglycemia, hypertension and dyslipidemia (elevated triglyceride (TG) levels and low high-density lipoprotein cholesterol (HDL-C).1 Although there is debate surrounding the concept of MetS, it is demonstrable that MetS is a major and prevalent risk factor for incidence of cardiovascular disease and diabetes.2 It has been reported that risk for atherosclerotic cardiovascular disease and type 2 diabetes are double and fivefold, respectively, among patients with MetS.3 In addition to metabolic and genetic susceptibilities, diet and physical activity are important factors, and MetS occurs more often among those who consume excessive nutrients, have an unhealthy dietary pattern, and are physically inactive.4,5 Sedentary lifestyle and consumption of a high-calorie diet has led to an increased prevalence of MetS in recent decades and makes it a critical problem faced by health care system.6 Several strategies are suggested for the management of MetS. Changing lifestyle (diet and physical activity) is regarded a cornerstone and first step to control metabolic disorders involved with this syndrome.7,8 Moreover, several dietary strategies have been investigated during recent years.9, 10, 11
Calorie restriction (CR) diet, decreasing energy intake by 15–40% of daily needs,12 is a common dietary manipulation for weight loss, and frequently uses for clinical practices. Although the positive result of CR diet has been documented among several diseases in which obesity/overweight is known as a risk factor,13,14 the compliance of the diet by patients over long periods is usually low. Another dietary strategy that may be more feasible than CR diet in practice is an Alternate Day Fasting (ADF) regimen which consists of a "fast day" where intake is limited to 25% of the individual's energy needs (approximately 500 calories), alternating with a "feed day" where food is consumed ad-libitum.15,16 Compared to CR, ADF diet has exhibited greater participant compliance in longer periods,17 and beneficial effect of ADF on healthy, diabetic and cardiovascular disease patients has been reported in several studies. However, there is currently a lack of sufficient data regarding the influence of these diets on MetS. Therefore, the present study sought to compare the therapeutic effect of ADF and CR dietary intervention on patients with MetS.
Section snippets
Participants
This study was a single-center, randomized clinical trial that was conducted from December 2015 to March 2016 among patients with Mets, referres to Sediqe-Tahere Heart Center, Isfahan, Iran. MetS was diagnosed according to the Revised National Cholesterol Education Program Third Adult Treatment Panel (RNCEP: ATPIII) definition.18 The patients were eligible to enter the study if they were aged 25–60 and overweight (25 ≤ BMI ≤ 40 kg/m2). Individuals with weight changes ≥5% for 3 months preceding
Diet protocol
All participants were instructed to follow their special diet which was prescribed based on their group and total energy need. The energy requirements for the individuals were calculated using the Mifflin equation.21 Patients in the ADF group were asked to consume a very low calorie diet (75% energy restriction) during the 3 fast days (Saturday, Monday, Wednesday) and then ate a diet that providing 100% of their energy needs on each feed day (Sunday, Tuesday, Thursday). On Friday, subjects were
Assessment of variables
Fasting blood samples were acquired to measure cholesterol, Triglycerides (TG), High- Density Lipoprotein Cholesterol (HDL-C), Low- Density Lipoprotein Cholesterol (LDL- C), Fasting Plasma Glucose (FPG), Fasting Insulin (FI). Participants were fasted for 12 h and samples were obtained between 7.00 am to 9.00 am at baseline and post- treatment (week 10) for biochemical analysis. Blood was centrifuged for 10 min at 520 × g at 4 °C to separate plasma from RBCs, and was stored at -70 °C until
Statistical analysis
Statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS) software version 20 (SPSS Inc., Chicago, USA). The Kolmogorov-Smirnov test was used to check the normal distribution of data. Independent samples t-test and chi-square was applied to compare the difference among continuous and categorical variables between 2 groups at baseline, respectively. Analysis of covariance (ANCOVA) was used to detect the difference of variable changes between 2 groups after
Results
Of 105 subject which were primarily assessed for inclusion/exclusion criteria, 70 patients were eligible and randomly assigned to either ADF or CR groups. Only one patient from the CR group was excluded due to being lost to follow up. Therefore, 69 participants (ADF = 35 and CR = 34) completed the trial and were included to final analysis (Fig. 1). No significant difference was found between two groups in term of age, sex, body weight, WC, systolic blood pressure (SBP), diastolic blood pressure
Discussion
The present study evaluated the effect of following a ADF diet in comparison to CR on adults with MetS for 8-weeks. The results demonstrated that in comparison to a CR diet, adherence to an ADF diet has a more beneficial effect on reducing body weight and WC, and improving in SBP and FPG levels. However, findings of the present study do not suggest any difference between following ADF and CR diet on BMI, lipid profile, DBP, HOMA-IR and fasting insulin concentrations.
MetS has become a major
Conclusion
In summary, this study suggests that ADF is a more effective strategy in managing body weight and WC, and reveals superior improvements in SBP and FPG in comparison to CR. These findings indicate that ADF diet may be a more beneficial therapeutic option in managing MetS. With regard to known limitations in compliance with CR diets, ADF presents a promising option, which results in more beneficial effects, in a short time frame. An ADF diet can be regarded useful, not only for metabolic syndrome
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Authorship
A. Parvaresh, R. Razavi, and S. M. Safavi equally contributed to the conception and design of the research; S. M. Safavi and N. Mohammadifard contributed to the design of the research; R. Razavi and Kh. Yaghooblo contributed to the acquisition and analysis of the data; A. Hassanzadeh and B. Abbasi contributed to the interpretation of the data; and A. Parvaresh, A. Hadi and C. Clark drafted the manuscript. All authors critically revised the manuscript, agree to be fully accountable for ensuring
Declaration of Competing Interest
None.
Acknowledgements
The authors would like to thank all the study participants. They are also grateful to the all staff for their support and cooperation.
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