Table 2 Summary of the direct evidence on effects of IF on metabolic outcomes in included meta-analyses
Comparison | No. of studies | No. of population | Population characteristics | Diet duration (months) | Mean difference (95% CI) | I2 | AMSTAR2 | GRADE | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
IF form | Reference diet | BMI | Disease | |||||||||
Normal | Overweight | Obesity | ||||||||||
Anthropometric measures | ||||||||||||
BW, kg | ||||||||||||
TRE | Usual | 5 | 131 | ✓ | ✓ | ✓ | preDM | 1~2 | -0.38 (-0.71, -0.05) | 0 | Critically low | Low |
ADF | 7 | 269 | ✓ | ✓ | ✓ | - | 1~12 | -4.30 (-5.54, -3.05) | 96 | Critically low | Very low | |
5:2/4:3 | 6 | 348 | ✓ | ✓ | ✓ | - | 3~6 | -4.83 (-5.46, -4.21) | 3 | Low | Low | |
TRE | CER | 8 | - | ✓ | ✓ | ✓ | - | 1~16 | -2.41 (-5.14, 0.33) | 42 | Low | Moderate |
ADF | 8 | 393 | ✓ | ✓ | ✓ | - | 0.75~6.5 | -0.17 (-1.03, 0.69) | 76.2 | Critically low | Very low | |
5:2 | 8 | 700 | - | ✓ | ✓ | - | 3~13 | -0.02 (-0.17, 0.13) | 0 | Low | High | |
5:2/4:3 | 13 | 991 | ✓ | ✓ | ✓ | T2DM | 3~13 | -0.55 (-1.01, -0.09) | 0 | Low | Moderate | |
STIER | 5 | 317 | - | ✓ | ✓ | - | 3.5~12 | -1.36 (-3.23, 0.51) | 37.6 | Critically low | Low | |
TRE | Usual/CER | 17 | 899 | ✓ | ✓ | ✓ | MetS, NAFLD, T2DM | 1.3~12 | -1.60 (-2.27, -0.93) | 90.2 | Low | Low |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | 0.39 (-1.68, 2.46) | - | Critically low | Very low |
BMI, kg/m2 | ||||||||||||
ADF | Usual | 4 | 293 | ✓ | ✓ | ✓ | - | 1~3 | -0.96 (-1.42, -0.50) | 52 | Critically low | Low |
TRE | CER | 4 | - | ✓ | ✓ | ✓ | - | 1~16 | -0.66 (-2.22, 0.91) | 51 | Low | Moderate |
ADF | 5 | - | ✓ | ✓ | ✓ | - | 1~16 | -0.66 (-1.57, 0.24) | 45 | Low | Moderate | |
5:2 | 5 | 436 | - | ✓ | ✓ | T2DM | 3~13 | 0.08 (-0.11, 0.27) | 0 | Low | High | |
TRE | Usual/CER | 8 | 616 | ✓ | ✓ | ✓ | MetS, NAFLD, T2DM | 2~12 | -0.53 (-1.10, 0.04) | 84.5 | Low | Low |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | 0.45 (0.01, 0.89) | - | Critically low | Very low |
FM, kg | ||||||||||||
TRE | Usual | 4 | 100 | ✓ | - | - | - | 1.3~2 | -0.83 (-1.89, 0.24) | 31 | Critically low | Low |
ADF | 6 | 226 | ✓ | ✓ | ✓ | - | 1~12 | -4.96 (-8.08, 1.85) | 99 | Critically low | Very low | |
5:2/4:3 | 6 | 279 | ✓ | ✓ | ✓ | - | 3~6 | -2.54 (-3.78, -1.31) | 62 | Low | Low | |
TRE | CER | 5 | - | ✓ | ✓ | ✓ | - | 1~16 | -2.58 (-4.55, 0.61) | 45 | Low | Moderate |
ADF | 6 | - | ✓ | ✓ | ✓ | - | 1~16 | -2.80 (-6.34, 0.74) | 78 | Low | Low | |
5:2 | 5 | 438 | - | ✓ | ✓ | T2DM | 3~24 | 0.06 (-1.02, 1.14) | 0 | Low | High | |
5:2/4:3 | 10 | 743 | - | ✓ | ✓ | T2DM | 3~13 | -0.66 (-1.14, -0.19) | 0 | Low | High | |
TRE | Usual/CER | 13 | 629 | ✓ | ✓ | ✓ | NAFLD | 1.3~12 | -1.48 (-1.59, -1.38) | 32 | Low | High |
TRE | ADF | 1 | 185 | ✓ | ✓ | ✓ | - | 3 | 0.55 (-0.30, 1.40) | - | Critically low | Very low |
FFM, kg | ||||||||||||
TRE | Usual | 4 | 100 | ✓ | - | - | - | 1.5~2 | 0.00 (-0.78, 0.79) | 0 | Critically low | Low |
TRE | CER | 5 | - | ✓ | ✓ | ✓ | - | 1~16 | -1.27 (-2.82, 0.29) | 2 | Low | High |
ADF | 5 | 342 | - | ✓ | ✓ | - | 3~6.5 | 0.08 (-0.13, 0.30) | 0 | Low | Moderate | |
5:2 | 5 | 438 | - | ✓ | ✓ | T2DM | 1~24 | -0.23 (-0.97, 0.51) | 29 | Low | High | |
WC, cm | ||||||||||||
ADF | Usual | 2 | 201 | - | ✓ | ✓ | - | 3 | -2.41 (-4.95, 0.13) | 63.1 | Critically low | Low |
5:2/4:3 | 2 | 142 | - | ✓ | ✓ | - | 3 | -1.73 (-3.69, 0.24) | 0 | Low | Moderate | |
TRE | CER | 6 | - | ✓ | ✓ | ✓ | - | 1~16 | -3.66 (-6.08, 1.24) | 38 | Low | High |
ADF | 3 | - | ✓ | ✓ | ✓ | - | 1~16 | -1.37 (-4.08, 1.34) | 28 | Low | High | |
5:2 | 5 | 393 | - | ✓ | ✓ | - | 3~6.5 | -0.06 (-0.26, 0.14) | 0 | Low | Moderate | |
5:2/4:3 | 8 | 641 | - | ✓ | ✓ | T2DM | 3~10.5 | -0.57 (-1.56, 0.41) | 0 | Low | High | |
TRE | Usual/CER | 7 | 512 | ✓ | ✓ | ✓ | MetS, NAFLD | 2~12 | -0.07 (-0.98, 0.83) | 0 | Low | High |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | 3 | 0.39 (-0.95, 1.73) | - | Critically low | Very low | |
Blood pressure | ||||||||||||
SBP, mmHg | ||||||||||||
TRE | Usual | 2 | 33 | ✓ | - | - | - | 2 | -2.27 (-19.52, 14.98) | 88.9 | Critically low | Very low |
ADF | 4 | 175 | ✓ | ✓ | ✓ | - | 1~12 | -4.42 (-7.35, -1.49) | 84 | Critically low | Very low | |
5:2/4:3 | 5 | 254 | ✓ | ✓ | ✓ | - | 3 | -6.11 (-9.59, -2.64) | 0 | Low | Moderate | |
TRE | CER | 4 | - | ✓ | ✓ | ✓ | - | 1~16 | -3.19 (-7.63, 1.26) | 0 | Low | High |
ADF | 3 | - | ✓ | ✓ | ✓ | - | 1~16 | -4.34 (-14.50, 5.83) | 79 | Low | Low | |
5:2 | 4 | 301 | - | ✓ | ✓ | - | 3~6.5 | 0.20 (-0.03, 0.42) | 0 | Low | Moderate | |
5:2/4:3 | 8 | 572 | - | ✓ | ✓ | T2DM | 3~6.5 | 0.24 (-2.08, 2.55) | 0 | Low | High | |
TRE | Usual/CER | 8 | 454 | ✓ | ✓ | ✓ | MetS | 1.3~12 | -2.46 (-6.43, 1.51) | 77.4 | Low | Low |
DBP, mmHg | ||||||||||||
TRE | Usual | 2 | 33 | ✓ | - | - | - | 2 | -2.76 (-19.52, 14.98) | 88.1 | Critically low | Very low |
ADF | 4 | 175 | ✓ | ✓ | ✓ | - | 1~12 | -3.41 (-5.91, -0.92) | 80 | Critically low | Very low | |
TRE | CER | 4 | - | ✓ | ✓ | ✓ | - | 1~16 | -3.47 (-7.00, 0.06) | 0 | Low | Moderate |
ADF | 3 | 239 | - | ✓ | ✓ | - | 3~6.5 | -0.04 (-0.29, 0.22) | 0 | Low | Moderate | |
5:2 | 3 | 224 | - | ✓ | ✓ | - | 3~6.5 | -0.04 (-0.30, 0.22) | 0 | Low | Moderate | |
TRE | Usual/CER | 8 | 454 | ✓ | ✓ | ✓ | MetS | 1.3~12 | -1.78 (-4.72, 1.16) | 72.2 | Low | Low |
Glycemic parameters | ||||||||||||
FBG, mg/dl | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | -2.45 (-4.72, -0.17) | 0 | Critically low | Low |
ADF | 4 | 144 | ✓ | ✓ | ✓ | - | 2~6 | -3.02 (-6.52, 0.48) | 89 | Critically low | Very low | |
5:2/4:3 | 4 | 224 | - | ✓ | ✓ | - | 3 | -2.16 (-7.38, 3.24) | 43 | Low | Low | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | -0.09 (-0.57, 0.40) | - | Low | Very low |
ADF | 3 | 225 | ✓ | ✓ | ✓ | - | 1~6 | -1.34 (-4.74, 2.06) | 55.6 | Critically low | Low | |
5:2 | 7 | 545 | - | ✓ | ✓ | - | 3~13 | 0.15 (-0.02, 0.33) | 89 | Low | Low | |
5:2/4:3 | 8 | 584 | - | ✓ | ✓ | T2DM | 3~10.5 | 1.08 (-0.54, 2.70) | 5 | Low | High | |
TRE | Usual/CER | 12 | 676 | ✓ | ✓ | ✓ | NAFLD, T2DM | 1~6 | -4.08 (-7.74, -0.42) | 96.6 | Low | Low |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | -2.52 (-8.01, 2.97) | - | Critically low | Very low |
FI, μIU/ml | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | -0.69 (-1.64, 0.26) | 48.9 | Critically low | Very low |
ADF | 2 | 67 | - | ✓ | ✓ | - | 2~3 | -1.50 (-10.11, 7.11) | 0 | Critically low | Moderate | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | 0.02 (-0.46, 0.51) | - | Low | Very low |
ADF | 3 | 226 | - | ✓ | ✓ | - | 2~6 | 0.12 (-2.34, 2.59) | 55.8 | Critically low | Low | |
5:2 | 4 | 315 | - | ✓ | ✓ | - | 3~13 | -0.09 (-0.31, 0.14) | 81 | Low | Very low | |
HbA1c, % | ||||||||||||
5:2/4:3 | Usual | 1 | 101 | - | ✓ | ✓ | - | 3 | 0.00 (-0.08, 0.08) | - | Low | Very low |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | -0.01 (-0.50, 0.47) | - | Low | Very low |
5:2 | 4 | 388 | - | ✓ | ✓ | GDM, T2DM | 3~13 | 0.01 (-0.19, 0.21) | 65 | Low | Moderate | |
5:2/4:3 | 6 | 570 | - | ✓ | ✓ | MetS | 3~13 | -0.01 (-0.07, 0.06) | 0 | Low | High | |
TRE | Usual/CER | 6 | 355 | - | ✓ | ✓ | MetS, T2DM | 2~6 | -0.11 (-0.50, 0.27) | 98.8 | Low | Very low |
Lipid profile | ||||||||||||
TG, mg/dl | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | 6.24 (-13.40, 25.88) | 86.8 | Critically low | Very low |
ADF | 5 | 208 | ✓ | ✓ | ✓ | - | 2~12 | -11.27 (-20.53, -2.00) | 96 | Critically low | Very low | |
5:2/4:3 | 5 | 254 | ✓ | ✓ | ✓ | - | 3 | -17.71 (-33.66, -2.66) | 52 | Low | Low | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | -0.02 (-0.51, 0.47) | - | Low | Very low |
ADF | 3 | 225 | ✓ | ✓ | ✓ | - | 2~6 | -5.87 (-32.06, 20.32) | 50.5 | Critically low | Low | |
5:2 | 6 | 494 | ✓ | ✓ | ✓ | - | 3~13 | 0.06 (-0.12, 0.24) | 25 | Low | High | |
5:2/4:3 | 8 | 587 | - | ✓ | ✓ | T2DM | 3~10.5 | -3.54 (-11.51, 5.31) | 0 | Low | High | |
TRE | Usual/CER | 13 | 767 | ✓ | ✓ | ✓ | MetS, NAFLD, T2DM | 1.3~12 | -8.64 (-18.01, 0.73) | 97 | Low | Low |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | 16.81 (-29.84, 63.47) | - | Critically low | Very low |
TC, mg/dl | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | 9.14 (-3.69, 21.96) | 80.9 | Critically low | Very low |
ADF | 5 | 174 | ✓ | ✓ | ✓ | - | 2~12 | -11.32 (-18.20, -4.44) | 96 | Critically low | Very low | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | 0.00 (-0.48, 0.49) | - | Low | Very low |
ADF | 3 | 225 | - | ✓ | ✓ | - | 2~6 | -2.79 (-11.31, 5.74) | 0 | Critically low | Moderate | |
5:2 | 6 | 494 | - | ✓ | ✓ | - | 3~13 | -0.2 (-0.37, -0.02) | 51 | Low | Low | |
TRE | Usual/CER | 10 | 657 | ✓ | ✓ | ✓ | NAFLD, T2DM | 1~12 | -6.10 (-7.86, -4.34) | 4.6 | Low | High |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | 8.49 (-6.09, 23.08) | - | Critically low | Very low |
LDL-C, mg/dl | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | 3.99 (-6.41, 14.39) | 69.3 | Critically low | Very low |
ADF | 4 | 151 | ✓ | ✓ | ✓ | - | 2~12 | -5.82 (-10.45, -1.19) | 92 | Critically low | Very low | |
5:2/4:3 | 5 | 254 | ✓ | ✓ | ✓ | - | 3 | -1.44 (-5.40, 2.70) | 67 | Low | Very low | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | -0.07 (-0.55, 0.42) | - | Low | Very low |
ADF | 3 | 229 | - | ✓ | ✓ | - | 3~6.5 | 0.00 (-0.26, 0.26) | 0 | Low | Moderate | |
5:2 | 6 | 494 | - | ✓ | ✓ | - | 3~13 | -0.20 (-0.38, -0.02) | 0 | Low | High | |
5:2/4:3 | 8 | 579 | - | ✓ | ✓ | T2DM | 3~10.5 | 0.00 (-1.98, 1.98) | 19 | Critically low | Moderate | |
TRE | Usual/CER | 10 | 689 | ✓ | ✓ | ✓ | NAFLD, T2DM | 1.3~12 | -3.63 (-8.05, 0.78) | 81.3 | Low | Low |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | -3.09 (-12.55, 6.37) | - | Critically low | Very low |
HDL-C, mg/dl | ||||||||||||
TRE | Usual | 4 | 90 | ✓ | ✓ | ✓ | preDM | 1.3~2 | 1.36 (-1.43, 4.14) | 53.9 | Critically low | Very low |
ADF | 5 | 174 | ✓ | ✓ | ✓ | - | 2~12 | -1.05 (-2.92, 0.83) | 71 | Critically low | Low | |
TRE | CER | 1 | 65 | - | ✓ | ✓ | MetS | 3 | 0.18 (-0.31, 0.66) | - | Low | Very low |
ADF | 3 | 229 | - | ✓ | ✓ | - | 3~6.5 | -0.34 (-0.61, -0.08) | 79 | Low | Moderate | |
5:2 | 6 | 494 | - | ✓ | ✓ | - | 3~13 | 0.05 (-0.12, 0.23) | 0 | Low | High | |
TRE | Usual/CER | 12 | 755 | ✓ | ✓ | ✓ | NAFLD, T2DM | 1~12 | 0.75 (-0.73, 2.24) | 73.6 | Low | Moderate |
TRE | ADF | 1 | 185 | - | ✓ | ✓ | - | 3 | -0.77 (-5.40, 3.85) | - | Critically low | Very low |