Table 1. Study Characteristics of Included Studies.
| Source, y, and country | Duration, RCT typea | Baseline participant characteristics | Intervention groups | Energy balance, macronutrient distribution and cointerventions | Outcomes measured | |||
|---|---|---|---|---|---|---|---|---|
| No. of participants (% female) | Age, mean (SD), y | Population health | BMI, mean (SD)b | |||||
| Time-restricted eating | ||||||||
| Che et al,33 2021 China | 12 wk, parallel | 120 (45.0) | C: 48.7 (9.5) I: 48.2 (9.3) |
T2D overweight and obese | C: 26.1 (2.1) I: 26.4 (2.0) |
C: Eat ad libitum per usual habits I: 10 h TRE (ad libitum), 8 am-6 pm |
No instruction provided on energy intake or macronutrient distribution | Weight, fasting glucose, HbA1c, LDL-C, energy intake, adherence |
| Chow et al,34 2020 US | 12 wk, parallel | 20 (85.0) | C: 44.2 (12.3) I: 46.5 (12.4) |
Healthy overweight and obese | C: 34.4 (7.8) I: 33.8 (7.6) |
C: Eat ad libitum per usual habits I: 8 h TRE (ad libitum during self-selected eating window) |
No instruction provided on energy intake or macronutrient distribution | Weight, FFM, lean mass, HbA1c, fasting glucose, LDL-C, BP, adherence, energy intakec |
| de Oliveira Maranhao Pureza et al,35 2021 Brazil | 52 wk, parallel | 58 (100.0) | C: 31.0 (7.1) I: 31.8 (6.9) |
Healthy obese women | C: 33.1 (3.6) I: 33.5 (4.5) |
C: Daily energy restriction I: 12 h TRE (self-selected eating window) |
ER = TEE – 500-1000 kcal/d Individualized meal plan based on usual diet. |
Weight, BMI, WC, BP, energy intake |
| Dhurandhar et al,36 2014 Denmark and US | 16 wk, parallel | 309 (75.7) | C: 42.1 (11.2) I: 42.0 (12.4) |
Healthy overweight and obese | Not stated | C: Usual eating habits; followed general good nutrition habits I: No energy intake before 11 am |
Each group provided with USDA pamphlet with instructions related to their specific intervention | Weight, adherence |
| Jamshed et al,40 2022 US | 14 wk, parallel | 90 (80.0) | C: 43.0 (11.0) I: 43.0 (10.0) |
Healthy obese | C: 39.2 (6.8) I: 40.1 (6.6) |
C: Self-selected ≥12 h eating window I: 8 h TRE (7 am-3 pm) |
ER = REE – 500 kcal/d Encouraged to increased exercise to 75-150 min/wk |
Weight, WC, FFM, fasting glucose, HbA1c, LDL-C, BP, adherence, energy intake, hunger and satiety (VAS)c |
| Kunduraci et al,42 2020 Turkey | 12 wk, parallel | 70 (51.4) | C: 48.7 (2.1) I: 47.4 (2.2) |
Metabolic syndrome overweight and obese | C: 32.8 (4.1) I: 36.5 (5.3) |
C: Daily energy restriction I: 8 h TRE (self-selected eating window) |
ER = −25% of habitual energy intake Personalized meal plan based on Turkey National Dietary Guidelines (Mediterranean diet) |
Weight, BMI, WC, FFM, BP, LDL-C, fasting glucose, HbA1c, energy intakec |
| Lin et al,15 2023 US | 52 wk, parallel | 60 (83.3) | C: 44.0 (13.0) I: 44.0 (12.0) |
Healthy obese | C: 38.0 (5.0) I: 37.0 (6.0) |
C: Maintained weight, physical activity habits and ≥10 h baseline eating window I: 8 h TRE (ad libitum 12-8 pm); at 26 wk, eating window widened to 10 h |
No instruction provided on energy intake or macronutrient distribution | Weight, BMI, WC, lean mass, fasting glucose, HbA1c, LDL-C, BP, adherence, energy intakec |
| Liu et al,43 2022 China | 52 wk, parallel | 139 (48.9) | C: 32.3 (8.8) I: 31.6 (9.3) |
Healthy overweight and obese | C: 31.3 (2.6) I: 31.8 (2.9) |
C: No time restriction I: 8 h TRE (8 am-4 pm) |
ER = 1500-1800 kcal/d for men and 1200-1500 kcal/d for women Macronutrient distribution (40%-55% carbohydrate, 15%-20% protein, 20%-30% fat) |
Weight, BMI, WC, lean mass, fasting glucose, LDL-C, BP, energy intake, adherencec |
| Lowe et al,45 2020 US | 12 wk, parallel | 116 (39.7) | C: 46.1 (10.3) I: 46.8 (10.8) |
Healthy overweight and obese | C: 32.6 (3.4) I: 32.9 (4.9) |
C: 3 meals daily (7-11 am, 11 am-3 pm, 4-10 pm); snacking between meals was permitted I: 8 h TRE (ad libitum, 12-8 pm) |
No instruction provided on energy intake or macronutrient distribution | Weight, BMI, WC, lean mass, fasting glucose, HbA1c, LDL-C, BP, adherence, energy intakec |
| Manoogian et al,46 2022 US | 12 wk, parallel | 137 (9.0) | C: 39.6 (9.4) I: 41.1 (8.7) |
Healthy fire fighters | C: 27.7 (3.9) I: 27.8 (3.6) |
C: No time restriction I: 10 h TRE (ad libitum during self-selected window) |
No ER Mediterranean diet (60% carbohydrates, 15% protein and 25% fat) |
Weight, BMI, HbA1c, fasting glucose, BP, LDL-C, energy intake, adherence |
| Montero et al,18 2023 Spain | 12 wk, parallel | 197 (50.0) | C: 46.7 (6.0) I: 46.8 (6.3) |
Overweight and obese with ≥1 cardiometabolic risk factor | C: 33.4 (3.6) I: 32.9 (3.3) |
C: Usual care I1: 8 h TRE (starting by 10:00 am) I2: 8 h TRE (starting by 1:00 pm) I3: 8 h TRE (self-selected eating window) |
No ER Education on Mediterranean diet |
Weight, lean mass, BP, fasting glucose, LDL-C, HbA1cc |
| Pavlou et al,19 2023 US | 26 wk, parallel | 75 (71.0) | C:54.0 (11.0) I:56.0 (13.0) |
Obese and T2D | C: 39.0 (7.0) I: 39.0 (9.0) |
C: Usual care I:8 h TRE (ad libitum 12-8 pm) |
No ER General healthy eating instructions |
Weight, HbA1c, lean mass, WC, BMI, BP, LCL-C, energy intake, adherencec |
| Philips et al,49 2021 Switzerland | 26 wk, parallel | 54 (NA) | C: 42.5 (14.0) I: 44.3 (12.8) |
Metabolic syndrome | C: 27.0 (4.0) I: 28.0 (4.1) |
C: Usual care I: 12 h TRE (ad libitum, self-selected eating window) |
No instruction provided on energy intake or macronutrient distribution | Weight, BMI, WC, BP, fasting glucose, HbA1c |
| Roman et al,50 2020 US | 26 wk, parallel | 24 (NA) | C and I: 41.6 (11.3) | Relapse Remitting Multiple Sclerosis | 25.1 (4.9) | C: Usual diet I: 8 h TRE (ad libitum, self-selected eating window) |
No instruction provided on energy intake or macronutrient distribution | Weight, BMI, adherence |
| Suthutvoravut et al,20 2023 Thailand | 12 wk, parallel | 46 (69.6) | C: 52.2 (7.9) I: 55.5 (7.2) | Prediabetes overweight and obese | C: 30.3 (3.2) I: 29.2 (2.9) |
C: Usual care I: 9 h TRE (ab libitum 8 am-5 pm) |
No instruction provided on energy intake or macronutrient distribution | Weight, fasting glucose, HbA1c, LDL-C, BP |
| Thomas et al,51 2022 US | 39 wk, parallel | 81 (85.2) | C: 37.8 (7.8) I: 38.3 (7.9) |
Healthy overweight and obese | C: 35.2 (4.7) I: 34.8 (6.4) |
C: No time restriction I: 10 h TRE (starting within 3 h of waking) |
ER = REE – 10% Encouraged to perform 150 min/wk of moderate activity |
Weight, BMI, FFM, fasting glucose, HbA1c, LDL-C, BP, adherence, energy intake, hunger and satiety (VAS and TFEQ)c |
| Wei et al,21 2023 China | 52 wk, parallel | 88 (44.3) | C: 31.7 (8.3) I: 32.3 (10.5) |
NAFLD obese | C: 32.2 (3.2) I: 32.2 (3.4) |
C: No time restriction I: 8 h TRE (8 am-4 pm) |
ER = 1500-1800 kcal/d for men and 1200-1500 kcal/d for women Macronutrient composition (40% to 55% carbohydrate, 15% to 20% protein, and 20% to 30% fat) |
Weight, BMI, WC, FFM, fasting glucose, HbA1c, LDL-C, BP, adherence, energy intakec |
| Meal frequency | ||||||||
| Bachman et al,32 2012 US | 26 wk, parallel | 51 (57.8) | I1: 51.8 (9.1) I2: 50.2 (10.8) |
Healthy overweight or obese | I1: 34.9 (4.3) I2: 36.1 (5.2) |
I1: 3Mdiet I2: Grazing group: ≥100kcal every 2-3 h (approximately 10 snacks) |
ER = 1200 kcal/d for participants ≤200 lbs 1500 kcal/d for participants >200 lbs Fat intake restricted to <30% energy Encouraged to increase physical activity to 200 min moderate intensity per wk |
BMI, FFM, energy intakec |
| Forslund et al,37 2008 Sweden | 52 wk, parallel | 140 (74.0) | I1: 38.7 (11.6) I2: 40.1 (11.5) |
Healthy obese | I1: 38.3 (5.3) I2: 38.4 (6.0) |
I1: 3Mdiet I2: 3 snacks plus 3 meals per day |
Energy restriction = TEE – 30% (minimum 1400 kcal/d) | Weight, BMI, fasting glucose, LDL-C, BP, energy intake |
| Grangeiro et al,14 2021 Brazil | 13 wk, parallel | 47 (100.0) | I1 [n = 19]: 29.05 (9.18) I2 [n = 21]: 30.33 (6.72) |
Healthy obese women | I1: 34.9 (1.6) I2: 35.2 (3.9) |
I1: 6Mdiet I2: 3Mdiet |
ER = TEE – 700 kcal Macronutrient distribution: 57% carbohydrates, 23% fat, 20% protein |
Weight, BMI, WC, FFM, fasting glucose, LDL-C, energy intake, adherencec |
| Jakubowicz et al,39 2019 Israel | 12 wk, parallel | 35 (61.0) | I1: 68 (8.6) I2: 69.5 (5.6) |
Insulin-treated T2D | I1: 32.1 (5) I2: 32.6 (5) |
I1:3Mdiet, large breakfast and smaller dinner I2: 6M diet (breakfast, lunch, dinner, and 3 snacks, even distribution) |
ER = REE – 500 kcal Macronutrient distribution: 40% carbohydrates, 35% fat, 25% protein |
Weight, fasting glucose, HbA1c, hunger (VAS) |
| Kahleova et al,41 2014 Czech Republic | 12 wk, crossover | 54 (46.0) | 59.4 (7.0) | T2D and overweight or obese | 32.6 (4.9) | I1: 6Mdiet I2: 2Mdiet (breakfast and lunch). |
ER = REE – 500 kcal Macronutrient distribution: 50%-55% carbohydrates, 20%-25% protein, <30% fat (<7% saturated fat) Meals provided for 50% of participants in each group |
Weight, BMI, WC, fasting glucose, HbA1c, LDL-C, energy intake |
| Papakonstantinou et al,47 2016 Greece | 12 wk, crossover | 40 (100.0) | 27.0 (1.0) | Women with PCOS | I1: 27.3 (1.0) I2: 27.2 (0.9) |
I1: 3Mdiet I2: 6Mdiet |
Energy maintenance Macronutrient distribution: 40% carbohydrates, 25% protein, 35% fat |
Weight, BMI, WC, HbA1c, fasting glucose, LDL-C, energy intake, hunger, satiety |
| Papakonstantinou et al,48 2018 Greece | 12 wk, crossover | 35 (57.1) | I1: 48.5 (3.2) I2: 52.1 (2.7) |
Prediabetes with overweight or obesity | I1: 32.6 (1.4) I2: 32.5 (1.2) |
I1: 3Mdiet I2: 6Mdiet |
Energy maintenance Macronutrient distribution: 45% carbohydrates, 20% protein, 35% fat |
Weight, BMI, WC, hunger, satiety, energy intake, HbA1c, fasting glucose, LDL-C |
| Papakonstantinou et al,48 2018 Greece | 12 wk, crossover | 12 (41.7) | I1: 52.1 (2.7) I2: 51.7 (3.5) |
Newly diagnosed treatment-naïve T2D with overweight or obesity | I1: 32.5 (1.2) I2: 32.2 (1.5) |
I1: 3Mdiet I2: 6Mdiet |
Energy maintenance Macronutrient distribution: 45% carbohydrates, 20% protein, 35% fat |
Weight, BMI, WC, hunger, satiety, energy intake, HbA1c, fasting glucose, LDL-C |
| Zargaran et al,52 2014 Iran | 12 wk, parallel | 90 (80.0) | NA (20-60 y) | Healthy overweight | C: 30.3 (4.7) I: 30.9 (5.2) |
C: Normal diet (most consisted of 3 meals and 2 snacks) I: 6Mdiet (iso-caloric meals) |
ER = TEE – 400 kcal | BMI, LDL-C |
| Calorie distribution | ||||||||
| Jakubowicz et al,38 2013 Israel | 12 wk, parallel | 93 (100.0) | I1: 45.1 (7.46) I2: 46.5 (6.86) |
Metabolic syndrome overweight and obese | I1: 32.3 (0.2) I2: 32.2 (0.2) |
I1: HCB (breakfast 700 kcal, lunch 500 kcal, dinner 200 kcal) I2: HCD (breakfast 200 kcal, lunch 500 kcal, dinner 700 kcal) |
ER = 1400 ± 25 kcal | Weight, BMI, WC, BP, LDL-C, fasting glucose, hunger, satiety, adherence |
| Lombardo et al,44 2014 Italy | 12 wk, parallel | 42 (100.0) | C: 43.0 (16.0) I1: 39.0 (17.0) |
Healthy overweight and obese | C: 35.1 (4.5) I1: 35.8 (5.2) |
C: Equal energy distribution (55% energy from breakfast, morning snack and lunch; 45% energy from afternoon snack and dinner) I: Front loading energy distribution (70% energy from breakfast, morning snack and lunch; 30% energy from afternoon snack and dinner) |
ER = TEE – 600 kcal Macronutrient composition: 16% protein, 25% fat, 59% carbohydrates |
Weight, BMI, WC, lean mass, fasting glucose, LDL-C, BP, energy intakec |
| Madjd et al,16 2016 Iran | 12 wk, parallel | 80 (100.0) | I1: 33.9 (7.3) I2: 33.3 (6.7) |
Healthy overweight and obese women | I1: 32.2 (2.2) I2: 32.1 (2.3) |
I1: Middle loading (energy distribution: 15% breakfast, 15% snacks, 50% lunch, 20% dinner) I2: Backloading (energy distribution: 15% breakfast, 15% snacks, 20% lunch, 50% dinner) |
ER (specifics unknown) Macronutrient composition: 17% protein, 23% fat (<10% saturated fat), 60% carbohydrate) Encouraged to increase physical activity to 60 min moderate activity 5 d/wk |
Weight, BMI, WC, LDL-C, fasting glucose, HbA1c, energy intake |
| Madjd et al,17 2021 Iran | 12 wk, parallel | 82 (100.0) | I1: 35.1 (7.4) I2: 34.9 (7.1) |
Healthy overweight and obese | I1: 32.7 (2) I2: 32.7 (2) |
I1: Early dinner eaten between 7-7:30 pm I2: Late dinner eaten between 10:30-11 pm |
ER = TEE – 500-1000 kcal Energy distribution: 15% breakfast, 15% snacks, 50% lunch, 20% dinner Macronutrient composition: 17% protein, 23% fat (<10% saturated fat), 60% carbohydrate Encouraged to increase physical activity to 60 min moderate activity 5 d/wk |
Weight, BMI, WC, fasting glucose, HbA1c, LDL-C, energy intake, adherence |
Abbreviations: 2Mdiet, 2 meals per day; 3Mdiet, 3 meals per day; 6Mdiet, 6 meals per day; BMI, body mass index; BP, blood pressure; C, control group; ER, energy restriction; FFM, fat-free mass; HbA1c, glycated hemoglobin; HCB, high-calorie breakfast; HCD, high-calorie dinner; I, intervention group; LDL-C, low-density lipoprotein cholesterol; NA, not available; NAFLD, nonalcoholic fatty liver disease; PCOS, polycystic ovary syndrome; RCT, randomized clinical trial; REE, resting energy expenditure; T2D, type 2 diabetes; TEE, total energy expenditure; TFEQ, Three Factor Eating Questionnaire; TRE, time-restricted eating; USDA, United States Department of Agriculture; VAS, visual analog scale; WC, waist circumference.
a
Follow-up duration in most studies was equal to intervention duration.
b
Calculated as weight in kilograms divided by height in meters squared.
c
Lean mass and FFM have both been reported as lean mass in this study.