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. 2021 Dec 17;4(12):e2139558. doi: 10.1001/jamanetworkopen.2021.39558

Table 2. Summary of Significant Associations of Intermittent Fasting With Health Outcomes.

Source Outcome Population Duration of fasting Type of IF Control No. of studies Sample size (IF/control) Metric Random effect size (95% CI) P value I2, % GRADE rating AMSTAR-2 rating
Anthropometric measures
Cui et al,25 2020 BMI Healthy adults, some with overweight, obesity, or NAFLD 1-2 mo MADF RD 4 82/54 MD −1.20 (−1.44 to −0.96) <.001 0 High Low
Park et al,28 2020 BMI Adults with overweight or obesity 2-3 mo MADF RD, CER, or TRE 8 307/298 MD −0.80 (−1.17 to −0.43) <.001 48.4 Low Moderate
Park et al,28 2020 BMI Adults with overweight or obesity 2-6 mo MADF RD, CER, or TRE 9 374/366 MD −0.73 (−1.13 to −0.34) .001 53.2 Very low Moderate
He et al,27 2021 Body weight, kg Adults with overweight or obesity 2-3 mo MADF CER 2 39/39 MD −1.65 (−2.73 to −0.58) .003 0 Moderate Moderate
He et al,27 2021 Body weight, kg Adults with overweight or obesity with no comorbidities 2-6 mo MADF CER 3 73/73 MD −1.42 (−2.44 to −0.41) .006 0 Moderate Moderate
Park et al,28 2020 Body weight, kg Adults with overweight, some with NAFLD 1-3 mo MADF CER, TRE, or RD 8 307/299 MD −1.77 (−3.19 to −0.34) .02 55.5 Very low Moderate
He et al,27 2021 Body weight, kg Adults with overweight or obesity, some with diabetes 3 mo 5:2 diet RD or CER 3 117/173 MD −1.67 (−2.79 to −0.55) .003 0 Very low Moderate
Pellegrini et al,26 2020 Body weight, kg Normal weight healthy male adults, some with prediabetes 1-2 mo TRE 12-24 h RD or CER 5 44/41 MD −0.38 (−0.71 to −0.04) .03 0 Low Low
He et al,27 2021 Fat-free mass, kg Adults with obesity 2-6 mo MADF CER 3 73/73 MD −0.70 (−1.38 to −0.02) .04 0 Moderate Moderate
Cui et al,25 2020 Fat-free mass, kg Healthy adults, some with overweight or obesity 1-12 mo MADF RD 5 89/73 MD −1.38 (−2.26 to −0.49) .002 91.0 Low Low
Park et al,28 2020 Fat mass, kg Adults with overweight or obesity 1-2 mo 0-calorie ADF RD or CER 2 39/39 MD −1.99 (−2.59 to −1.38) <.001 0 Moderate Moderate
He et al,27 2021 Fat mass, kg Adults with obesity 2-6 mo MADF CER 3 73/73 MD −1.05 (−1.98 to −0.13) .03 0 Very low Moderate
Park et al,28 2020 Fat mass, kg Adults with overweight or obesity, some with NAFLD 2-3 mo MADF RD, CER, or TRE 5 233/225 MD −1.08 (−1.91 to −0.26) .01 31.7 Very low Moderate
Cui et al,25 2020 Fat mass, kg Healthy adults, some with overweight or obesity 1-12 mo MADF RD 6 119/107 MD −4.96 (−8.08 to −1.85) .002 99.0 Very low Low
Park et al,28 2020 Fat mass, kg Adults with overweight or obesity, some with NAFLD 2-6 mo MADF RD, CER, or TRE 6 300/293 MD −0.96 (−1.91 to −0.004) .049 43.0 Very low Moderate
Moon et al,5 2020 Fat mass, kg Adults with overweight or obesity 2-3 mo TRE 12-21 h RD 3 112/96 MD −2.40 (−2.98 to −1.82) <.001 0 Low Moderate
Lipid profile
Meng et al,7 2020 LDL-C, mg/dL Adults with normal weight, overweight, or obesity 3-12 mo MADF RD with exercise 5 139/140 MD −5.14 (−7.44 to −2.83) <.001 0 Very low Moderate
Meng et al,7 2020 LDL-C, mg/dL Adults with normal weight, overweight, or obesity 2-12 mo MADF RD with exercise 7 156/154 MD −5.23 (−7.52 to −2.94) <.001 0 Very low Moderate
Park et al,28 2020 TC, mg/dL Adults with overweight or obesity, some with NAFLD 2-3 mo MADF RD, CER, or TRE 5 250/241 MD −10.95 (−18.98 to −2.93) .007 2.7 Very low Moderate
Park et al,28 2020 TC, mg/dL Adults with overweight or obesity, some with NAFLD 2-6 mo MADF RD or CER 6 317/309 MD −8.13 (−15.79 to −0.46) .04 19.9 Very low Moderate
Meng et al,7 2020 TG, mg/dL Adults with overweight or obesity with no comorbidities 2 mo MADF RD or RD with exercise 2 17/14 MD −26.84 (−52.33 to −1.35) .04 0 Low Moderate
Park et al,28 2020 TG, mg/dL Adults with overweight or obesity, some with NAFLD 2-3 mo MADF RD, CER, or TRE 5 250/241 MD −21.67 (−39.44 to −3.89) .02 0 Very low Moderate
Glycemic profile
Pellegrini et al,26 2020 FPG, mg/dL Healthy adults, some with overweight, obesity, or chronic diseases 1-2 mo TRE 12-24 h RD or CER 4 57/56 MD −2.45 (−4.72 to −0.18) .04 0 Very low Low
Pureza et al,8 2020 FPG, mg/dL Adults with overweight 4 d to 3 mo TRE 12-21 h RD or TRE 12-15 h 7 148/147 MD −2.75 (−4.6 to −0.91) .003 88.7 Very low Moderate
He et al,27 2021 Fasting insulin, mIU/mL Female adults with overweight or obesity 3-6 mo 5:2 diet CER 2 90/94 MD −1.00 (−1.77 to −0.39) .002 0 Moderate Moderate
Pureza et al,8 2020 HOMA-IR Healthy adults; some with overweight, obesity, or prediabetes 1 d to 2 mo TRE 18 h RD 4 59/60 MD −0.51 (−0.82 to −0.19) .002 50.8 Very low Moderate
Blood pressure
Cui et al,25 2020 SBP, mmHg Healthy adults, some with overweight or obesity 1-12 mo MADF RD 4 90/85 MD −4.42 (−7.35 to −1.49) .003 84.0 Very low Low
Cui et al,25 2020 DBP, mmHg Healthy adults, some with overweight or obesity 1-12 mo MADF RD 4 90/85 MD −3.41 (−5.91 to −0.92) .003 80.0 Very low Low

Abbreviations: AMSTAR-2, A Measurement Tool to Assess Systematic Reviews; BMI, body mass index; CER, continuous energy restriction; DBP, diastolic blood pressure; FPG, fasting plasma glucose; HOMA-IR, homeostatic model assessment of insulin resistance; IF, intermittent fasting; LDL-C, low-density lipoprotein cholesterol; MADF, modified alternate-day fasting; MD, mean difference; NAFLD, nonalcoholic fatty liver disease; RD, regular diet; SBP, systolic blood pressure; TC, total cholesterol; TG, triglycerides; TRE, time-restricted eating.