Table 2.
Studies identified on the role of intermittent fasting (IF) on obesity and diabetes.
| Authors, Year and Country | Study Duration | Sample Size | Type of Study | Exhibition Time | The Purpose of the Study | Main Effects Observed | LE | GR |
|---|---|---|---|---|---|---|---|---|
| Sutton et al., 2018 [16] Los Angeles, USA | 2013–2016 |
n =12 8 patients finished the trial |
Randomized clinical trial | 5 weeks | To find out the effects of early time-restricted feeding on insulin sensitivity, blood pressure, and oxidative stress in men with prediabetes. | Improved insulin sensitivity, β-cell responsiveness, blood pressure, oxidative stress, and appetite. | 1++ | A |
| Li et al., 2017 [17] Berlin, Germany | 2015 |
n = 46 36 patients finished the trial |
Randomized clinical trial | 7 days | To investigate the effects of a one-week fasting period compared to usual care in type 2 diabetes mellitus using a pilot trial. | Decreased mean weight, reduction of abdominal circumference, decrease of systolic/diastolic blood pressure, and increased quality of life. No improvement in HbA1c, insulin, and Homeostatic Model Assessment for Insulin Resistance index. | 1++ | A |
| Antoni et al., 2016 [18] Guilford, UK |
- |
n = 14 10 patients finished the trial |
Randomized clinical trial | 3 days | To investigate the early metabolic response to various degrees of energy restriction, which occurs acutely and before weight loss. | Increased postprandial glucose responses, reductions in postprandial triacylglycerol responses, and 3-day energy intake deficits. | 1++ | A |
| Sundfør et al., 2018 [19] Oslo, Norway | 2015–2017 | n = 112 | Randomized clinical trial | 12 months | To compare the effects of intermittent versus continuous energy restriction in relation to weight loss, maintenance, and cardiometabolic risk factors in adults with abdominal obesity and ≥1 additional component of metabolic syndrome. | Improvement in weight loss, maintenance, and cardiovascular risk factors (waist circumference, blood pressure, triglycerides, and HDL-cholesterol) after one year but with no differences between intermittent and continuous energy restriction. | 1++ | A |
| Harney et al., 2019 [23] Adelaida, Australia |
2013–2015 |
n = 88 85 patients finished the trial |
Randomized clinical trial | 10 weeks (2 weeks with normal diet + 8 weeks with intermittent fasting) | To perform a proteomic analysis of human plasma during IF in sedentary people. | Increased apolipoprotein A4 and clusterin and decreased apolipoprotein C2, apolipoprotein A2, C3, and plasma triglycerides. | 1++ | A |
| Jamshed et al., 2019 [20] Birmingham, USA |
- | n = 11 | Randomized clinical trial | 4 days | To determine how time-restricted feeding affects gene expression, circulating hormones, and diurnal patterns in cardiometabolic risk factors in humans. | Decreased mean 24-h glucose and glycemic excursions, altered lipid metabolism, and circadian clock gene expression. | 1++ | A |
| Anton et al., 2019 [21] Florida USA |
- | n = 10 | Randomized clinical trial | 4 weeks | To assess the safety and feasibility of time-restricted feeding in an overweight sedentary older adult population. | Decreased body weight, no significant changes in other outcome (waist circumference, cognitive and physical function, health-related quality of life, and adverse events) except for clinically meaningful changes in walking speed and improvements in quality of life, with few reported adverse events. | 1++ | A |
| Liu et al., 2019 [6] Adelaida, Australia | - | n = 76 | Randomized clinical trial | 8 weeks | To compare the effects of daily caloric restriction vs. IF on markers of inflammation and extracellular matrix deposition in adipose tissue and skeletal muscle in a controlled feeding trial in overweight or obese women. | Markers of inflammation in serum, subcutaneous adipose tissue, and skeletal muscle were unchanged after fed days. After fasting, non-esterified fatty acids (NEFA), M1-macrophages in adipose tissue and M2-macrophages in muscle were increased, and the changes in NEFA and mRNA of pan-macrophage marker CD68 in adipose tissue were positively correlated. | 1++ | A |
| Kim et al., 2020 [24] London, UK |
2016 | n = 43 | Randomized clinical trial | 4 weeks | To investigate the effects of intermittent and continuous energy restriction on cognition related to the neurogenesis of the human hippocampus. | Significantly improved pattern separation and significant deterioration in recognition memory. | 1++ | A |
| Jospe et al., 2020 [22] Dunedin, New Zealand |
2014–2015 | n = 250 | Randomized clinical trial | 12 weeks | To investigate the implication of dietary intake, weight loss, and metabolic outcomes in overweight adults who could choose to follow Mediterranean diets, intermittent fasting, and standard exercise or high-intensity interval training (HIIT) programs. | Weight loss and reduced systolic blood pressure. | 1++ | A |
Articles were classified using the scale proposed by the Scottish Intercollegiate Guidelines Network. LE: Level of evidence, GR: Grade of recommendations.