Long-term effects of weight loss with a very-low carbohydrate, low saturated fat diet on flow mediated dilatation in patients with type 2 diabetes: A randomised controlled trial

- A very low carbohydrate diet that limits saturated fat level (LowCHO) does not impair flow mediated dilatation (FMD).
- A high carbohydrate, low fat (HighCHO) diet and a LowCHO diet produce similar improvements in HbA1c.
- A HighCHO diet and a LowCHO diet produce similar weight loss.

Background and aimsVery-low carbohydrate diets can improve glycaemic control in patients with type 2 diabetes (T2DM). However, compared to traditional higher carbohydrate, low fat (HighCHO) diets, they have been associated with impaired endothelial function (measured by flow mediated dilatation [FMD]) that is possibly related to saturated fat.This study aimed to examine the effects of a 12-month hypocaloric very-low carbohydrate, low saturated fat (LowCHO) diet compared to an isocaloric HighCHO diet.MethodsOne hundred and fifteen obese patients with T2DM (age:58.4 ± 0.7 [SEM] yr, BMI:34.6 ± 0.4 kg/m2, HbA1c:7.33 [56.3 mmol/mol] ± 0.10%) were randomised to consume an energy restricted LowCHO diet (Carb:Pro:Fat:Sat-Fat 14:28:58: < 10% energy; n = 58) or isocaloric HighCHO diet (53:17:30: < 10%; n = 57) whilst undertaking exercise (60 min, 3/wk). Bodyweight, HbA1c and FMD were assessed.ResultsSeventy eight participants completed the intervention (LowCHO = 41, HighCHO = 37). Both groups experienced similar reductions in weight and HbA1c (−10.6 ± 0.7 kg, −1.05 ± 0.10%; p < 0.001 time, p ≥ 0.48 time × diet). FMD did not change (p = 0.11 time, p = 0.20 time × diet).ConclusionsIn patients with obesity and T2DM, HighCHO diet and LowCHO diet have similar effects on endothelial function.