In type 2 diabetes, randomisation to advice to follow a low-carbohydrate diet transiently improves glycaemic control compared with advice to follow a low-fat diet producing a similar weight loss.
Study Goal
The researchers aimed to compare the effects of a low-fat diet (LFD) versus a low-carbohydrate diet (LCD) on weight and HbA1c in adults with type 2 diabetes over a 2-year intervention.
Results Summary
Weight loss did not differ significantly between the LFD and LCD groups, with maximal loss at 6 months. HbA1c reductions were observed only in the LCD group, and insulin doses were reduced more significantly with LCD at 6 months.
Population
61 adults with type 2 diabetes recruited from primary care, excluding non-Swedish speakers.
Effective Dosage
LFD aimed for 55-60 energy per cent (E%) from carbohydrates.
Duration
2 years
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
low-fat diet (LFD) | no change | weight loss | adults with type 2 diabetes | - | did not differ | #1 |
low-carbohydrate diet (LCD) | no change | weight loss | adults with type 2 diabetes | - | did not differ | #2 |
low-fat diet (LFD) | decrease | weight | patients on the LFD | -3.99 ± 4.1 kg | lost | #3 |
low-carbohydrate diet (LCD) | decrease | weight | patients on LCD | -4.31 ± 3.6 kg | lost | #4 |
low-fat diet (LFD) | decrease | weight | patients on the LFD | -2.97 ± 4.9 kg | lost | #5 |
low-carbohydrate diet (LCD) | decrease | weight | patients on LCD | -2.34 ± 5.1 kg | lost | #6 |
low-carbohydrate diet (LCD) | decrease | HbA(1c) | LCD group | -4.8 ± 8.3 mmol/mol | fell | #7 |
low-carbohydrate diet (LCD) | decrease | HbA(1c) | LCD group | -2.2 ± 7.7 mmol/mol | fell | #8 |
low-fat diet (LFD) | decrease | HbA(1c) | LFD | -0.9 ± 8.8 mmol/mol | fell | #9 |
low-carbohydrate diet (LCD) | increase | HDL-cholesterol | - | from 1.13 ± 0.33 mmol/l to 1.25 ± 0.47 mmol/l | had increased | #10 |
low-carbohydrate diet (LCD) | no change | LDL-cholesterol | - | - | did not differ | #11 |
low-fat diet (LFD) | no change | LDL-cholesterol | - | - | did not differ | #12 |
low-carbohydrate diet (LCD) | decrease | insulin doses | LCD group | from 42 ± 65 E to 30 ± 47 E | were reduced | #13 |
low-fat diet (LFD) | decrease | insulin doses | LFD | from 39 ± 51 E to 38 ± 48 E | were reduced | #14 |
AIMS/HYPOTHESIS: The study aimed to compare the effects of a 2 year intervention with a low-fat diet (LFD) or a low-carbohydrate diet (LCD), based on four group meetings to achieve compliance. METHODS: This was a prospective randomised parallel trial involving 61 adults with type 2 diabetes consecutively recruited in primary care and randomised by drawing ballots. Patients that did not speak Swedish could not be recruited. The primary outcomes in this non-blinded study were weight and HbA(1c). Patients on the LFD aimed for 55-60 energy per cent (E%) and those on LCD for 20 E% from carbohydrate. RESULTS: The mean BMI and HbA(1c) of the participants were 32.7 ± 5.4 kg/m(2) and 57.0 ± 9.2 mmol/mol, respectively. No patients were lost to follow-up. Weight loss did not differ between groups and was maximal at 6 months: LFD -3.99 ± 4.1 kg (n=31); LCD -4.31 ± 3.6 kg (n=30); p < 0.001 within groups. At 24 months, patients on the LFD had lost -2.97 ± 4.9 kg and those on LCD -2.34 ± 5.1 kg compared with baseline (p = 0.002 and p = 0.020 within groups, respectively). HbA(1c) fell in the LCD group only (LCD at 6 months -4.8 ± 8.3 mmol/mol, p = 0.004, at 12 months -2.2 ± 7.7 mmol/mol, p = 0.12; LFD at 6 months -0.9 ± 8.8 mmol/mol, p = 0.56). At 6 months, HDL-cholesterol had increased with the LCD (from 1.13 ± 0.33 mmol/l to 1.25 ± 0.47 mmol/l, p = 0.018) while LDL-cholesterol did not differ between groups. Insulin doses were reduced in the LCD group (0 months, LCD 42 ± 65 E, LFD 39 ± 51 E; 6 months, LCD 30 ± 47 E, LFD 38 ± 48 E; p = 0.046 for between-group change). CONCLUSIONS/INTERPRETATION: Weight changes did not differ between the diet groups, while insulin doses were reduced significantly more with the LCD at 6 months, when compliance was good. Thus, aiming for 20% of energy intake from carbohydrates is safe with respect to cardiovascular risk compared with the traditional LFD and this approach could constitute a treatment alternative. TRIAL REGISTRATION: ClinicalTrials.gov NCT01005498 FUNDING: University Hospital of Linköping Research Funds, Linköping University, the County Council of Östergötland, and the Diabetes Research Centre of Linköping University.