Table 1.
Characteristics of included studies on body weight changes among patients on diets based on intermittent energy restriction (IER) such as alternate-day fasting (ADF) and time-restricted feeding (TRF).
| ADF | |||||
|---|---|---|---|---|---|
| Characteristic of Group | Dropout Rate | Composition of Diet | Time of Therapy | Effect on Body Weight | |
| Heilbronn et al., 2005 [25] | 16 patients with BMI ranging from 20 to 30 kg/m2 |
- | Fasting days had 0% of energy intake, doubling the energy need on nonfasting days | 3 weeks | Reduction of FM and FFM |
| Halberg et al., 2005 [27] | 8 overweight males | - | Fasting days had 0% of energy intake for 20 h, with ad libitum intake on feeding days and at all other times |
2 weeks | Lack of bodyweight reduction |
| Varady et al., 2009 [31] | 16 obese patients: 12 females; 4 males | - | Fasting days met 25% of energy needs, and the following days were ad libitum | 8 weeks | Reduction of BW of 5.8 kg +/−1.1 kg |
| Varady et al., 2013 [32] | 12 overweight/obese males and females; 15 controls |
7% IER 7% control |
Fast days had 25% of energy intake, and the following days were ad libitum | 12 weeks | Reduction of body weight and FM, FFM with no change |
| Harvie et al., 2013 [22] | 75 overweight/obese females (IER-A: 37; IER-B: 38) | 11% IER-A 26% IER-B |
IER-A: fasting days had 30% intake of energy needs for 2 days/week and CER diet for 5 days/week IER-B: fasting days had 30% of energy intake plus 250 g of protein-rich food and CER diet for 5 days/week |
17 weeks | Similar reductions of body weight, FM, and FFM in both groups |
| Bhutani et al., 2013 [23] | Obese male and females: 25 IER; 18 IER + EX; 24 EX; 16 controls | 36% IER 33% EX 11% IER + EX |
IER fasting days met 25% of energy needs, and the following days were ad libitum EX: 3 times/week |
12 weeks | Reduction of body weight in every intervention group: IER + EX (6 ± 4 kg) > IER (3 ± 1 kg) = EX (1 ± 0 kg) |
| TRF | |||||
| Characteristic of Group | Dropout Rate | Composition of Diet | Time of Therapy | Effect | |
| Gill et al., 2015 [35] | 8 participants overweight/obese: 5 males; 3 females | - | 10 h eating period including nonwater beverages, with 14 h fasting window per day | 16 weeks | Reduction of body weight by about 3.6% |
| Wilkinson et al., 2020 [36] | 19 participants with obesity: 6 females; 13 males | - | 10 h eating period, with 14 h fasting window per day | 12 weeks | Reduction of body weight by about 3% |
| Peeke et al., 2021 [38] | 79 participants: 39 on TRF 12:12; 29 on TRF 14:10 | 30% Group 1 30% Group 2 |
Group 1: 12 h eating period, with 12 h fasting period per day Group 2: 10 h eating period, with 14 h fasting period per day |
8 weeks | Reduction of body weight by about 7.1% among Group 1 and about 8.5% among Group 2; the difference was not statistically significant |
| Gabel et al. [37] | 23 participants with obesity | - | 8 h eating window, with 16 h fasting period per day | 12 weeks | Reduction of body weight by about 2.6 +/−0.5% |
| Cienfuegos et al. [39] | 58 obese participants: 19 in Experimental Group 1; 20 in Experimental Group 2; 19 in control group | Experimental Group 1: 5% Experimental Group 2: 15% control group: 26% |
Experimental Group 1: 4 h eating window, with 20 h fasting period per day Experimental Group 2: 6 h eating window, with 18 h fasting window per day |
10 weeks (2 weeks of body weight stabilization and 8 weeks of TRF) | Significant reduction of body weight among both intervention groups compared to controls: 3.2 +/−0.4% weight loss among Groups 1 and 2 |
Note: BMI, body mass index; FM, fat mass; FFM, free fat mass; CER, continuous energy restriction; EX, exercise.