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Table 1 Characteristics of the included studies

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

Author
(year)
[ref]
Study design Participants Trial duration N Study groups Age (years) Males (n) BMI (kg/m2)
Waist-c (cm)
FM
FFM (kg)
SBP
DBP (mmHg)
Fasting glucose (mg/dL)
Hb1Ac (%)
Fasting insulin (µU/mL)
HOMA-IR (mmol/L * µU/mL)
Total chol (mg/dL) HDL-c (mg/dL) LDL-c (mg/dL) TG (mg/dL)
Antoni
(2018)
[22]
RCT 2 parallel arms BMI > 25 kg/m2
Age 18–65 years
No comorbidity
8–10 weeks 15a IER (2 days/week) = 25% of the energy need on 2 consecutive fast days and energy according to needs on feed days 42 ± 4 7 30 ± 1 31 ± 2 123 ± 3 79 ± 2 11 ± 1 162 ± 12 42 ± 4 100 ± 12 97 ± 9
102 ± 3 58 ± 3 74 ± 3 ND 1.6 ± 0.2     
12a CER: 600 kcal less than estimated needs 48 ± 3 6 31 ± 1 34 ± 3 115 ± 3 79 ± 4 9 ± 1 162 ± 12 39 ± 4 104 ± 8 80 ± 9
102 ± 2 56 ± 3 75 ± 3 ND 1.3 ± 0.1     
Carter
(2016)
[24]
RCT 2 parallel arms T2DM
BMI ≥ 27 kg/m2
Age ≥ 18 years
No comorbidity
12 weeks 31 IER (2 days/week) = 400–600 kcal/day on fast days and no restriction on feed days 61 ± 8 16 35 ± 5 38 ± 9 134 ± 17 ND ND ND ND ND ND
ND 55 ± 11 84 ± 10 7 ± 1      
32 CER = 1200–1500 kcal/day every day 62 ± 9 14 36 ± 5 40 ± 11 138 ± 15 ND ND ND ND ND ND
ND 54 ± 9 90 ± 11 8 ± 1      
Catenacci
(2016)
[27]
RCT 2 parallel arms BMI ≥ 30 kg/m2
Age 18–55 years
Non-smokers
No diabetes, CV diseases, major comorbidity
8 weeks 15 IER (3 days/week) = 0 kcal/day on fast days alternate and energy according to needs, but with the chance to ask for more food, on feed days 40 ± 10 3 36 ± 4 38 ± 8 ND 88 ± 7 13 ± 6 170 ± 33 38 ± 8 100 ± 31 143 ± 56
ND 53 ± 9   ND ND     
14 CER = 400 kcal less than needs 43 ± 8 3 40 ± 6 49 ± 10 ND 92 ± 8 19 ± 6 171 ± 36 39 ± 7 104 ± 29 140 ± 43
ND 61 ± 12   ND ND     
Conley
(2018)
[23]
RCT 2 parallel arms Men with BMI ≥ 30 kg/m2
Age 55–75 years
No diabetes
No high alcohol intake or major comorbidity
24 weeks 12 IER (2 days/week) = 600 kcal/day on 2 non-consecutive fast days and energy ad libitum on feed days 68 ± 3 12 33 ± 2 ND 142 ± 14 108 ± 27 ND 151 ± 35 45 ± 12 77 ± 31 168 ± 53
114 ± 5   84 ± 10 ND
12 CER = 500 kcal less than needs 67 ± 4 12 36 ± 4 ND 150 ± 18 110 ± 31 ND 166 ± 39 46 ± 12 98 ± 35 212 ± 150
123 ± 10   88 ± 14 ND
Coutinho
(2017)
[28]
RCT 2 parallel arms BMI = 30–40 kg/m2
Age 18–65 years
Inactive, no menopause or major comorbidity
12 weeks 18 IER (3 days/week) = 550–660 kcal/day on fast days and energy according to needs on feed days 39 ± 11 4 36 ± 3 47 ± 8 ND ND ND ND ND ND ND
ND 60 ± 12
17 CER = 33% of energy restriction every day 39 ± 9 2 35 ± 4 43 ± 8 ND ND ND ND ND ND ND
ND 55 ± 9
Harvie
(2011)
[26]
RCT 2 parallel arms BMI = 24–40 kg/m2
Premenopausal women
Age 30–45 years
Non-smokers, not using OC, no major comorbidity
24 weeks 53 IER (2 days/week) = 25% of the energy need on 2 consecutive fast days and energy according to needs on feed days 40 ± 4 0 31 ± 5 34 (31–36) 115 (111–119) 87 (85–88) 7 (6–8) 197 (189–197) 58 (54–58) 119 (112–127) 106 (88–124)
102 (98–105) 48 (46–49) 77 (74–79) ND 1.5 (1.3–1.8)     
54 CER = 25% energy restriction every day 40 ± 4 0 31 ± 5 35 (32–39) 117 (113–120) 87 (83–88) 7 (6–9) 200 (193–208) 62 (54–66) 119 (108–127) 115 (97–124)
102 (99–106) 49 (48–50) 75 (72–78) ND 1.6 (1.3–1.8)
Harvie
(2013)
[20]
RCT 3 parallel arms Women with BMI = 24–45 kg/m2 or body fat > 30% of BW
Age 30–45 years
No major comorbidity
12 weeks 37 IER (2 days/week) = 25% of the energy need on 2 consecutive fast days and energy according to needs on feed days 46 ± 8 0 30 ± 4 31 (28–34) 115 (111–125) 88 (85–90) 6 (5–8) 204 (191–229) 50 (49–59) 128 (116–139) 088 (75–102)
101 (97–104) 48.5 (46–50) ND 5 1.6 (1.3–1.9)  
38 IER as above plus unlimited proteins and fats (non-SFA) on fast days 49 ± 7 0 31 ± 6 34 (30–37) 130 (115–138) 90 (86–92) 7 (6–9) 221 (206–237) 55 (51–59) 144 (130–159) 95 (81–109)
104 (99–109) 49 (47–51) ND 6 1.9 (1.5–2.2)
40 CER = daily 25% restriction every day 48 ± 8 0 32 ± 6 36 (32–39) 124 (116–131) 90 (86–92) 7 (6–9) 205 (193–218) 51 (48–55) 129 (118–139) 97 (83–111)
106 (102–110) 50 (48–52) ND 6 1.8 (1.5–2.2)
Sundfor
(2018)
[21]
RCT 2 parallel arms BMI = 30–45 kg/m2
Age 21–70 years
Waist ≥ 84/90 cm (male/female) plus another component of the metabolic syndrome
No comorbidity or alcohol/drug
abuse
24 weeks 54 IER (2 days/week) = 400–600 kcal/day on 2 non-consecutive fast days and energy as usual on feed days 50 ± 10 28 35 ± 4 ND 129 ± 13 104 ± 22 ND 192 ± 35 47 ± 13 126 ± 32 162 ± 73
116 ± 10   88 ± 8 6 ± 1
58 CER = 400–600 kcal less than needs 48 ± 12 28 35 ± 4 ND 128 ± 13 103 ± 13 ND 197 ± 34 45 ± 10 133 ± 32 137 ± 60
116 ± 10   86 ± 9 6 ± 1
Trepanowski
(2017)
[17]
RCT 3 parallel arms BMI = 25.0–39.9 kg/m2
Age 18–65 years
Non-smokers, inactive
No menopause, diabetes, CV diseases
24 weeks 34 IER (alternate d/week) = 25% of the energy need on fast days and 125% of energy needs on feed days 44 ± 10 4 34 ± 4 38 ± 7 124 ± 12 90 ± 12 16 ± 14 188 ± 35 57 ± 14 111 ± 13 101 ± 59
ND 55 ± 9 83 ± 9 ND ND
35 CER = daily 25% restriction every day 43 ± 12 6 35 ± 4 40 ± 7 122 ± 17 92 ± 18 20 ± 18 184 ± 35 53 ± 11 112 ± 31 97 ± 27
ND 58 ± 12 80 ± 11 ND ND
31 C = no dietary intervention 44 ± 11 4 34 ± 4 36 ± 10 121 ± 16 87 ± 8 16 ± 9 190 ± 30 59 ± 13 112 ± 31 98 ± 43
ND 53 ± 10 81 ± 11 ND ND
Varady
(2011)
[19]
RCT 4 parallel arms BMI = 25–39.9 kg/m2
Age 35–65 years
Non-smokers, inactive
No diabetes, CV diseases
12 weeks 15 IER (3 days/week) = 25% of the energy need on fast days and ad libitum on feed days 47 ± 2 3 32 ± 2
ND
ND ND ND ND ND 51 ± 3 141 ± 9 ND
15 CER = 25% energy restriction every day 47 ± 3 2 32 ± 2
ND
ND ND ND ND ND 60 ± 6 137 ± 9 ND
15 Moderate exercise program, no diet intervention 46 ± 3 2 33 ± 1
ND
ND ND ND ND ND 51 ± 4 122 ± 9 ND
15 C = no dietary/exercise intervention 46 ± 3 2 32 ± 2
ND
ND ND ND ND ND 57 ± 3 136 ± 10 ND
Williams
(1998)
[25]
RCT, 3 parallel
Arms
T2DM
Age 30–70 years
BW > 20% ideal
Not currently on insulin, no liver, renal, heart diseases
20 weeks 18 IER (1 day/week) = 400–600 kcal/day on fast day and 1500–1800 kcal/day on feed days 51 ± 8 9 35 ± 5 ND ND 177 ± 56 20 ± 11 215 ± 37 41 ± 8 132 ± 35 197 ± 83
ND    8 ± 2 ND
18 IER (5 days/week) = 400–600 kcal/day on fast day every 5 weeks and 1500–1800 kcal/day on feed days 50 ± 9 7 37 ± 5 ND ND 182 ± 58 17 ± 7 208 ± 39 42 ± 7 131 ± 29 203 ± 239
ND    8 ± 2 ND
18 CER = 1500–1800 kcal/day every day 54 ± 7 7 35 ± 5 ND ND 184 ± 61 22 ± 9 218 ± 42 46 ± 11 127 ± 48 167 ± 89
ND    8 ± 2 ND
  1. BMI body mass index, BW body weight, Chol cholesterol, CV cardiovascular, CER continuous energy restriction, DBP diastolic blood pressure, FFM fat free mass, FM fat mass, IER intermittent energy restriction, HDL-c high density lipoprotein-cholesterol, LDL-c low density lipoprotein-cholesterol, ND no data, OC oral contraceptives, RCT randomized controlled trial, SFA saturated fatty acids, SBP systolic blood pressure, TG triglycerides, T2DM type 2 diabetes mellitus, Waist-c waist circumference, Wk week
  2. aNot available the baseline data of all the randomized patients; the study reported the baseline characteristics of the study completers only
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