Characteristics of included studies
| Citation | Country | Study design | Setting, duration | Participants | Intervention intake (energy %) | Control intake (energy %) | Notes | Outcomes | Dropouts end of study (intervention/control) |
|---|---|---|---|---|---|---|---|---|---|
| Davis et al14 24 | USA | RCT, parallel groups | Outpatient, duration: 12 months | 105 subjects with type 2 diabetes, overall mean age: 54, 22% males. BMI 36 kg/m2 | At 6 months: 34% carb, 43% fat At 12 months: 33% carb, 44% fat | At 6 months: 48% carb, 31% fat At 12 months: 50% carb, 31% fat | Assigned to low-carb vs low-fat diet | 6 and 12 months HbA1c (%), weight, LDL cholesterol, medications, quality of life (Diabetes-39) | 20 (10/10) |
| Guldbrand et al15 25 | Sweden | RCT, parallel groups | Outpatient, duration: 24 months | 61 subjects with type 2 diabetes, mean age: 62, BMI: 33 kg/m2 | At 6 months: 25% carb, 49% fat, 24% protein At 12 months: 27% carb, 47% fat, 23% protein | At 6 months: 49% carb, 29% fat, 21% protein At 12 months: 47% carb, 31% fat, 20% protein | Assigned to 20% vs 59% carb diet | 6, 12, and 24 months HbA1c (%), weight, BMI, LDL cholesterol, medications, quality of life (SF-36) | 7 (3/4) |
| Krebs et al16 | New Zealand | RCT, parallel groups | Outpatient, duration: 12 months | 419 subjects with type 2 diabetes, mean age:58, 40% males, BMI: 37 kg/m2 | At 6 months: 45% carb, 22% protein At 12 months: 45% carb, 21% protein | At 6 months: 49% carb, 20% protein At 12 months: 48% carb, 21% protein | Assigned to 40% vs 55% carb diet | 6 and 12 (24 months follow-up) HbA1c (%), BMI, weight, LDL cholesterol, quality of life (SF-36) | 108 (55/53) |
| Elhayany et al21 | Israel | RCT, parallel groups | Outpatient, duration: 12 months | 259 subjects with type 2 diabetes, mean age:55, 53% males, BMI: 31.4 kg/m2 | Randomized to 35% carb, 45% fat, 15–20% protein | Randomized to 50–55% carb, 30% fat, 15–20% protein | ADA diet group (N=85) was not included as control | 12 months HbA1c (%), BMI, weight, LDL cholesterol | 48 (23/25) |
| Larsen et al17 | Australia | RCT, parallel groups | Outpatient, duration: 12 months | 108 subjects with type 2 diabetes, mean age: 58, 48% males | At 3 months: 40% carb, 28% protein At 12 months: 42% carb, 27% protein | At 3 months: 49% carb, 21% protein At 12 months: 48% carb, 19% protein | Assigned to 40% vs 55% carb | 3 and 12 months HbA1c (%), weight, LDL Cholesterol | 5 (4/1) |
| Iqbal et al22 | USA | RCT, parallel groups | Outpatient, duration 24 months | 144 subjects with type 2 diabetes, mean age: 60, 90% males | At 6 months: 35% carb, 43% fat At 12 months: 40% carb 33% fat | At 6 months: 42% carb, 37% fat, At 12 months: 43% carb, 36% fat | Assigned to 20 g carb/day vs a diet with <30% fat | 6, 12, and 24 months HbA1c (%), weight, LDL cholesterol | 76 (42/34) |
| Saslow et al18 | USA | RCT, parallel groups | Outpatient, duration 3 months | 34 subjects* with type 2 diabetes, mean age: 60, 26% males, BMI 37 kg/m2 | 14% carb, 58% fat, 24% protein | 41% carb, 35% fat, 21% protein | Assigned to ≤50 g carb per day vs a 45–50% carb diet | 3 months HbA1c (%), BMI, weight, LDL cholesterol depression scales, physical activity | 2 (1/1) |
| Tay et al19 | Australia | RCT, parallel groups | Outpatient, duration 3 months | 115 subjects with type 2 diabetes, mean age: 58, 57% males, BMI 34 kg/m2 | 14% carb, 54% fat, 27% protein | 50% carb, 25% fat, 19% protein | Assigned to 14% vs 53% carb diet | 3 months HbA1c (%), BMI, weight, LDL cholesterol, medications, physical activity | 25 (13/12) |
| Yamada et al20 | Japan | RCT, parallel groups | Outpatient, duration 6 months | 24 subjects with type 2 diabetes, mean age: 63, 50% males, BMI 26 kg/m2 | 30% carb, 45% fat, 25% protein | 51% carb, 32% fat, 17% protein | Assigned to 30% vs 55% carb diet | 6 months HbA1c (%), BMI, weight, LDL cholesterol, Problem areas in diabetes scale | 0 |
| Wolever et al23 | Canada | RCT, parallel groups | Outpatient, duration 12 months | 110 subjects with type 2 diabetes, mean age: 60, 44% males, BMI 31 kg/m2 | 39% carb, 40% fat, 19% protein | 52% carb, 27% fat, 21% protein | 52 subjects randomized to high-glycemic index group not included | 12 months HbA1c (%), BMI, weight, LDL cholesterol | 2 (1/1) |
*Saslow et al four subjects had baseline HbA1c between 6.0% and 6.5%.