Table 1:
Summary of recent time-restricted eating (TRE) studies and major findings
| Study | Study Cohort | Condition Characteristics | Duration, Design | TRE Protocol (duration, time, intake prescription) | Major Findings |
|---|---|---|---|---|---|
| Type 2 Diabetes | |||||
| Che et al., 2021 [14] | n=104 46% F 48±10 y 26±2 kg/m2 100% with overweight |
Type 2 diabetes HbA1c ~8.6%, 5±1 y since diagnosis, managed via diet, OHA and/or insulin | 12 weeks RCT |
10 hours 0800 – 1600 h ad libitum vs control (usual eating pattern, ~15 hours, ~0600 – 1830 h) |
Adherence: >6 d/wk, “compliance was excellent” Safety: no adverse events including hypoglycemia; Differences vs control: ↓ HbA1c (−0.8%), fasting glucose, body weight, BMI, HOMA-IR, medication effects score, triglycerides, total cholesterol, LDL; ↑ HOMA-β, QoL; Concurrent lifestyle behaviors: −28% EI (vs +5% control), ↔ PA. |
| Parr et al., 2020 [13] | n=19 53% F 50±9 y 34±5 kg/m2 100% with overweight |
Type 2 diabetes, HbA1c ~7.6%, 3±3 y since diagnosis, current medication of up to 2 OHAs excluding insulin, sulfonylurea, GLP-1 agonists | 4 weeks pre-post |
9 hours 1000 – 1900 h ad libitum |
Adherence: 72% (range: 4–100%); Safety: ↔ lean mass; no hypoglycemia or major adverse events; Changes from baseline: ↔ body weight, fat mass, HbA1c, fasting glucose; Concurrent lifestyle behaviors: ↔ EI or macronutrient intake; ↓ EI when adherent (↓ CHO, alcohol). |
| Cancer | |||||
| Kirkham et al., 2022 [15] | n=22 100% F 66±5 y 31±5 kg/m2 100% with overweight/obesity |
Breast cancer survivors aged ≥60 y with overweight, 3±1 years since anthracycline chemotherapy treatment | 8 weeks pre-post |
8 hours 1200 – 2000 h weekdays ad libitum |
Adherence: median 98%, range: 85–100%; Safety: ↔ fat-free mass, thigh muscle volume; minor symptoms (headache, irritability) lasting 5 minutes to 3 hours; no major adverse events; Changes from baseline: ↓ Framingham 10-year CVD risk, body weight and whole-body fat (bioelectrical impedance), visceral fat (magnetic resonance imaging); ↔ total cholesterol, HDL, SBP, BMI; Concurrent lifestyle behaviors: −22% (median) EI. |
| Kleckner et al., 2022 [17] | n=39 92% F 62±12 y 32±7 kg/m2 80% with overweight/obesity |
Any cancer diagnosis and fatigue ≥3 on 0–10 scale, 2±1 years since treatment | 2 weeks pre-post |
10 hours self-selected ad libitum |
Adherence: average 90% Safety: n=1 grade 1 headache; n=1 grade 1 insomnia; Changes from baseline: ↓ fatigue, drowsiness; ↑ QoL Concurrent lifestyle behaviors: ↔ sleep problems; −11±35% EI. |
| O’Donnell et al., 2022 [16] | n=40 100% F 60 y (34–76) 60% with overweight/obesity |
Breast cancer survivors completed treatment, median 4.5 y since diagnosis | 12 weeks pre-post | 11 hours timing NR ad libitum |
Adherence: median 93%, range 0–100%; Safety: NR; Changes from baseline: ↓ BMI, anxiety, depression, fatigue; ↔ lipid profile, HbA1c, leptin, adiponectin, C-Reactive Protein, IL-6, TNF-α, QoL Concurrent lifestyle behaviors: ↔ PA. |
| Overweight/Obesity | |||||
| Cienfuegos et al. 2022 [21] | n=49 91% F 47±3 y 37±1 kg/m2 |
Adults with obesity | 8 weeks RCT |
4 hours 1500 – 1900 h ad libitum (n=19) vs 6 hours 1300 – 1900 h ad libitum (n=20) vs control (n=19) |
Adherence: 89±2%; Safety: mild adverse effects, such as dizziness, nausea, headaches, constipation, diarrhea, and dry mouth in both TRE groups vs control; no major adverse events; ↔ lean mass; Differences vs control: ↓ body weight and fat mass, ↔ VAT; Concurrent lifestyle behaviors: −29–30% EI in both TRE groups; ↔ PA, sleep quality, or insomnia severity in any group. |
| Crose et al., 2021 [22] | n=20 85% F 46±12 y 34±8 kg/m2 |
Adults with overweight | 12 weeks RCT |
8 hours self-selected window ad libitum (n=11) vs control (n=9) |
Adherence: 95% of eating events in 10±2 h; Safety: NR; Changes from baseline: ↓ body weight (-3.7%); ↑ health transition QoL; Differences vs control: ↑ health transition QoL, emotional health QoL; Concurrent lifestyle behaviors: NR. |
| Karras et al., 2021 [23] | n=45 76% F ~48±9 y 29±6 kg/m2 |
Adults with overweight | 7 weeks non-RCT follow up at 13 weeks |
8 hours 0800 – 1600 h plus CR (F: 1200–1500 kcal/d M: 1500–1800 kcal/d) (n=16) vs Orthodox fasting (dawn-dusk) plus same CR (n=29) |
Adherence: NR; Safety: ↔ lean mass; Changes from baseline: ↓ body weight (7, 13 weeks), BMI, WC; ↑ HDL; ↔ body fat mass, total cholesterol, LDL, triglycerides, fasting glucose; Differences vs Orthodox fasting: NR; Concurrent lifestyle behaviors: ~-250 kcal/d EI, ↓ fiber intake. |
| Karras et al., 2022 [24] | n=97 100% F ~47±7 y 29±6 kg/m2 |
Premenopausal women with overweight | 7 weeks (48 d) non-RCT follow up at 12 weeks |
8 hours 0800 – 1600 h plus CR (F: 1200–1500 kcal/d M: 1500–1800 kcal/d) (n=42) vs Orthodox fasting (dawn- dusk) plus same CR (n=55) |
Adherence: NR; Safety: NR; Changes from baseline: ↓ BMI, WC (7, 12 wks); Differences vs Orthodox fasting: ↔ BMI, WC Concurrent lifestyle behaviors: ~-30% EI, ↓ monounsaturated and total fat intake, ↓ carbohydrate and protein intake. |
| Kotarsky et al, 2021 [25] | n=21 86% F 44±7 y 30±3 kg/m2 |
Adults with overweight/obesity | 8 weeks RCT |
8 hours 1200–2000 h ad libitum plus aerobic and resistance exercise training (n=11) vs aerobic and resistance exercise training (n=10) |
Adherence: “only two instances of non-compliance reported among two participants”; Safety: n=1 headache; no major adverse events; Changes from baseline: ↓ body weight, BMI, WC; Differences vs control: ↓ body weight, BMI; ↔ WC; Concurrent lifestyle behaviors: −15% EI in both groups; ↔ sedentary time or light PA in either group; ↔ group difference in moderate-vigorous PA. |
| Li et al., 2021 [28] | n=15 100% F 18–31 y (range) 30±4 kg/m2 |
Women (18–40 y) with polycystic ovarian syndrome and BMI ≥24 kg/m2 | 5 weeks pre-post |
8 hours 0800 – 1600 h ad libitum |
Adherence: NR; Safety: ↔ lean mass; Changes from baseline: ↓ body weight (−1.7%), BMI, fat mass, body fat percentage, VAT, fasting insulin, HOMA-IR, insulin response to oral glucose tolerance test, C-reactive Protein, alanine aminotransferase; ↑ menstrual cycle regularity, insulin-like growth fator-1; Concurrent lifestyle behaviors: ↔ eating behaviors. |
| Lin et al., 2021 [27] | n=63 100% F ~52±8 y 26±4 kg/m2 |
Women, aged 40–65 y with BMI ≥24 kg/m2 or WC >80 cm | 8 weeks RCT |
8 hours 1000 – 1800 h or 1200 – 2000 h plus CR (1400 kcal/d) (n=30) vs CR alone (1400 kcal/d) alone (n=33) |
Adherence: “around 84%”; Safety: NR; Changes from baseline: ↓ body weight (−4.5% TRE+CR; −2.4% CR alone), BMI, WC, body fat percentage, VAT; ↓ DBP (TRE+CR); ↑ fasting glucose, HOMA-IR (TRE+CR) Changes vs CR alone: ↓ body weight, BMI, DBP; Concurrent lifestyle behaviors: −9–11% EI; 13–19% carbohydrate intake. |
| Liu et al., 2022 [26] | n=139 (n=118 completed) 48% F 32±9 y 32±3 kg/m2 |
Adults with BMI of 28–45 kg/m2 | 12 months RCT |
8 hours 0800 – 1600 h plus 25% CR (n=69) vs 25% CR alone (n=70) |
Adherence: 84±16% (TRE+CR) vs 84±13% (CR alone); Safety: ↓ lean mass (↔ between groups), ↔ in adverse events between groups; Changes from baseline: ↓ body weight (-8.0 kg), fat mass (−5.9 kg), VAT, abdominal subcutaneous fat, liver fat, SBP, DBP; Differences vs control: ↔ body weight or any composition variables, SBP, DBP, lipid profile, markers of glucose or insulin control; Concurrent lifestyle behaviors: ↔ physical activity from baseline or between groups; ↔ group difference in EI. |
| Lobene et al., 2021 [29] | n=20 85% F 46±3 y 34±2 kg/m2 |
Adults with overweight | 12 weeks RCT |
8 hours self-selected window ad libitum (n=11) vs control (n=9) |
Adherence: 56±22%; Safety: ↓ lean mass relative to baseline and control; Changes from baseline: ↓ body weight (−3.7%), fat mass (-4.0%), VAT (-11.1%); ↔ bone mineral density; Differences vs control: ↓ body weight, VAT; ↑ bone mineral content; ↔ bone mineral density or bone turnover markers; Concurrent lifestyle behaviors: NR. |
| Peeke et al., 2021 [30] | n=60 88% F 44±11 y 38±9 kg/m2 |
Adults with obesity | 8 weeks RCT |
10 hours self-selected window with start 0700–1000 h/stop 1700–2000 h plus CR by −500–1000 kcal/d, with “fasting snack” (200 kcal ~0500–0800 h) vs 12 hours + same CR |
Adherence: NR; Safety: no adverse events; Changes from baseline: ↓ body weight (−10.7 kg, TRE+CR; −8.9 kg CR), fasting glucose Differences vs CR alone: ↓ body weight (−1.9 kg, −1.4%), ↔ fasting glucose; Concurrent lifestyle behaviors: NR. |
| Prasad et al., 2021 [31] | n=16 82% F 51±12 y 31±11 kg/m2 |
Adults with overweight/obesity | 3 months pre-post |
10 hours self-selected window ad libitum |
Adherence: 47±19%; Safety: NR; Changes from baseline: ↓ body weight (−2%), BMI, WC, SBP; Concurrent lifestyle behaviors: ↔ weight efficacy lifestyle questionnaire, morning-eveningness questionnaire. |
| Przulj et al., 2021 [32] | n=50 74% F 50±12 y 35±4 kg/m2 |
Adults with BMI ≥30 kg/m2 or BMI ≥28 kg/m2 with comorbidities | 12 weeks, pre-post |
8 hours self-selected window ad libitum |
Adherence: 5±2 d/wk; Safety: NR; Changes from baseline: ↓ body weight (-2.6 kg), rating of hunger; ↔ lipid profiles, SBP, DBP; Concurrent lifestyle behaviors: NR. |
| Querioz et al., 2022 [33] | n=37 84% F 30±6 y 31±3 kg/m2 |
Adults with BMI ≥25-≤34.9 kg/m2 | 8 weeks RCT |
8 hours 0800 – 1600 h plus −25% CR vs 8 hours 1200 – 2000 h plus −25% CR vs −25% CR alone |
Adherence: 85% and 73 % of participants in earlier and later TRE + CR group, respectively, were fully adherent; Safety: ↓ lean mass (↔ groups), ↓ RMR; Changes from baseline: ↓ body weight (−4.2 kg, −4.8 kg, −4.0 kg for 3 groups, fat mass, fasting glucose, insulin, total cholesterol, LDL, HDL; Concurrent lifestyle behaviors: ↔ PA, ↑ sleep quality. |
| Schroder et al., 2021 [20] | n=32 100% F 37±2 y 33±1 kg/m2 |
Women with obesity | 3 months non-RCT | 8 hours 1200 – 2000 h ad libitum (n=20) vs control (n=12) |
Adherence: NR; Safety: NR; Differences vs control: ↓ body weight, BMI, WC, SBP, DBP, Framingham 30-year CVD risk; ↑ QoL; Concurrent lifestyle behaviors: NR. |
| Thomas et al, 2022 [34] | n=81 85% F 38±8 y 34±6 kg/m2 |
Adults with BMI of 27–45 kg/m2 | 12 weeks RCT follow up at 39 weeks |
10 hours window starting within 3 h of waking plus −35% CR (n=32) vs −35% CR alone (n=31) |
Adherence: 5±1 days to TRE+CR vs 4±2 to CR alone; Safety: ↓ lean mass (↔ between groups); Changes from baseline: ↓ body weight, fat mass Differences between groups: ↔ body weight, fat mass Concurrent lifestyle behaviors: −500 kcal/d EI and ↑ health eating index in TRE+CR, ↔ PA. |
| Zhao et al., 2022 [35] | n=15 0% F 63±4 years 31±2 kg/m2 |
Men with WC ≥94 cm | 8 weeks pre-post |
10 hours window finished by 1930 h ad libitum |
Adherence: 88±10%; Safety: NR; Changes from baseline: ↓ body weight, WC, VAT, percentage body fat, fasting glucose, HbA1c; ↔ SBP, DBP, fasting insulin, total cholesterol, HDL, triglycerides, NEFAs; Concurrent lifestyle behaviors: ↔ EI or sleep duration; ↓ PA and total energy expenditure; |
Key: arrows indicate significant reductions (↓), increases (↑), or no significant changes/differences (↔). Abbreviations: BMI, body mass index; CR, calorie restriction; CVD, cardiovascular disease; DBP, diastolic blood pressure; EI, energy intake; F, females; HbA1c, glycated hemoglobin; HDL, high density lipoprotein; HOMA-IR, Homeostatic Model Assessment for Insulin Resistance; LDL, low density lipoprotein; NR, not reported; OHA, oral hypoglycemic agent; PA, physical activity; QoL, quality of life; RCT, randomized controlled trial; RMR, resting metabolic rate; SBP, systolic blood pressure; TRE, time-restricted eating; VAT, visceral adipose tissue; WC, waist circumference.