Table 2.
Characteristics of study design and study populations at baseline.
| Study | Country (Year) | Study Design | Type of Intervention | Study Length | Diagnosis | DM Medication | Gender (%F) | Group | n | Age (Years) | BMI (kg/m2) | HbA1c (%) | Intervention Description |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| [31] | Bahrain (2020) | Parallel | Low-GI food | 4 mo | T2DM | - | 61 | T | 100 | 20–65 | >22 | 6–10 | |
| I | 50 | 55.3 ± 2.7 | 28.5 ± 7.7 | 6.6 ± 0.8 | 3 dates consumed at breakfast | ||||||||
| C | 50 | 56.9 ± 4.4 | 29.9 ± 4.1 | 6.6 ± 0.7 | No date consumption | ||||||||
| [32] | Greece (2015) | Parallel | Low-GI/GL food | 3 mo | T2DM | No insulin | 53 | T | 58 | 40–65 | 25–40 | <8 | |
| I | 28 | 61.3 ± 1.4 | 32.7 ± 0.8 | 6.6 ± 0.1 | Hypocaloric diet + 4 weekly portions of low-GI/GL sweets | ||||||||
| C | 30 | 63.0 ± 1.3 | 32.4 ± 0.8 | 6.8 ± 0.2 | Hypocaloric diet + 1 weekly portion of favorite sweet | ||||||||
| [37] | Thailand (2018) | Parallel | Low-GI meal | 3 mo | T2DM | Any type | 65 | T | 110 | ≥18 | - | 7–9 | |
| I | 53 | 56.0 ± 8.9 | 27.9 ± 4.2 | 7.9 ± 0.7 | Low-GI meal replacement once per day with controlled diets | ||||||||
| C | 57 | 56.3 ± 10.0 | 27.7 ± 4.9 | 7.8 ± 0.6 | Controlled diets | ||||||||
| [38] | China (2017) | Parallel | Low-GI diet | 6 mo | T2DM | Oral medication |
46 | T | 130 | - | - | - | |
| I | 65 | 56.9 ± 3.9 | - | - | Low-GI high-fiber diet + exercise | ||||||||
| C | 65 | 56.4 ± 3.7 | - | - | High fiber diet + exercise | ||||||||
| [39] | Brazil (2017) | Parallel | Low-GI diet | 1 mo | T2DM | Metformin | 50 | T | 20 | 18–55 | - | - | |
| I | 10 | 44.3 ± 4.8 | 28.8 (22.5–33.9) | - | Low-GI diet + 2 daily low-GI test meals consumed in the lab | ||||||||
| C | 10 | 41.1 ± 3.2 | 28.6 (25.4–37.5) | - | High-GI diet + 2 daily high-GI test meals consumed in the lab | ||||||||
| [40] | Canada (2017) | Parallel | Low-GI diet | 6 mo | T2DM | No acarbose |
39 | T | 201 | - | - | 6.5–8 | |
| I | 102 | 60.2 ± 9.5 | 30.5 ± 6.1 | 7.2 ± 0.6 | Low-GI high-fiber diet | ||||||||
| C | 99 | 61.3 ± 8.7 | 31.0 ± 5.5 | 7.1 ± 0.5 | High-cereal fiber diet | ||||||||
| [41] | Canada (2022) | Parallel | Low-GI diet | 3 y | T2DM | No insulin | 39 | T | 169 | - | - | 6.5–8 | |
| I | 86 | 61 ± 9 | 30 ± 5 | 7.1 ± 0.6 | Low-GI diet | ||||||||
| C | 83 | 62 ± 6 | 29 ± 5 | 7.1 ± 0.5 | Wheat-fiber diet | ||||||||
| [42] | Germany (2014) | Parallel | Low-GI food | 6 wk | Pre-DM | None | 62 | T | 42 | 54 ± 8 | ≥25 | - | |
| I | 28 | - | 32.9 ± 3.2 | - | Hypocaloric diet + 2 daily low-GI meal replacements | ||||||||
| C | 14 | - | 32.8 ± 2.3 | - | Hypocaloric diet + healthy lifestyle | ||||||||
| [43] | China (2014) | Parallel | Low-GI meal | 3 mo | T2DM | No insulin | 39 | T | 54 | 18–75 | 18.5–35 | - | |
| I | 36 | 56.7 ± 8.6 | 24.6 ± 2.6 | 6.7 ± 0.9 | Breakfast replaced with a low-GI, multi-nutrient supplement | ||||||||
| C | 18 | 54.5 ± 10.1 | 23.7 ± 2.9 | 6.5 ± 0.6 | Healthy breakfast | ||||||||
| [44] | Spain (2020) | Crossover | Low-GI food | 10 wk | T2DM Pre-DM |
- | 38 | T | 43 | 55.8 ± 7.4 | 31.9 ± 3.1 | 6.0 ± 0.6 | |
| I | 42 | - | - | - | 66 mL/day of alcohol-free beer with modified CHO content | ||||||||
| C | 43 | - | - | - | 66 mL/day of regular alcohol-free beer | ||||||||
| [34] | India (2020) | Parallel | Low-GI diet | 6 mo | T2DM | Any type | 42 | T | 36 | 35–65 | ≤35 | 7–10 | |
| I | 18 | 52 ± 7.7 | 26.8 ± 5.0 | 8.3 ± 0.9 | Kerala cuisine low-GI diet | ||||||||
| C | 18 | - | 27.3 ± 2.7 | 8.2 ± 1.0 | Usual diet | ||||||||
| [33] | India (2020) | Parallel | Low-GI diet | 6 mo | T2DM | Any type | 35 | T | 80 | 35–65 | - | 7–10 | |
| I | 40 | 54.4 ± 7.6 | 26.4 ± 3.0 | 8.4 ± 1.0 | Kerala cuisine low-GI diet | ||||||||
| C | 40 | 51.9 ± 7.4 | 26.8 ± 3.3 | 8.3 ± 1.0 | Usual diet | ||||||||
| [35] | USA (2022) | Parallel | Low-GI diet | 1 mo | Pre-DM | None | 49 | T | 35 | 18–65 | - | - | |
| I | 17 | 58.1 ± 1.5 | 32.5 ± 1.2 | 5.8 ± 0.1 | Low-GI diet | ||||||||
| C | 18 | 50.6 ± 2.4 | 32.4 ± 1.5 | 5.8 ± 0.1 | High-GI diet | ||||||||
| [36] | Australia (2020) | Crossover | Low-GL diet | 2 mo | T2DM | No insulin | 36 | T | 17 | 58.0 ± 6.6 | 29.9 ± 3.5 | 7.0 ± 0.9 | |
| I | 17 | - | - | - | 20% daily energy intake replaced with lupin-enriched foods | ||||||||
| C | 17 | - | - | - | 20% daily energy intake replaced with wheat-based control foods |
BMI, body mass index; C, control group; CHO, carbohydrate; DM, diabetes mellitus; F, female; GI, glycemic index; GL, glycemic load; HbA1c; glycated hemoglobin; I, intervention group; mo, month; pre-DM, prediabetes; T, total sample; T2DM, type 2 diabetes mellitus; wk, week.