A web-based low carbohydrate diet intervention significantly improves glycaemic control in adults with type 2 diabetes: results of the T2Diet Study randomised controlled trial

Background/Objectives: In people with type 2 diabetes mellitus (T2DM), low carbohydrate diets (LCD; 10–<26% total energy from carbohydrate) improve glycaemic control and clinical outcomes. Web-based interventions may address accessibility barriers to dietary education/support for T2DM, yet no randomised controlled trial (RCT) had evaluated a web-based LCD intervention. This study assessed whether a web-based LCD programme, adjunct to standard care, improves glycaemic control in adults with T2DM. Subjects/Methods: A 16-week parallel RCT was conducted remotely in adults aged 40–89 years with T2DM not on insulin. Participants were randomised (1:1) to standard care plus access to the web-based T2Diet healthy LCD education programme (intervention) or standard care only (control). Primary outcome: haemoglobin A1c (HbA1c). Secondary outcomes: weight, BMI, anti-glycaemic medication (Medication Effect Score, MES), dietary intake, and self-efficacy. Analyses were blinded and intention-to-treat. Results: Ninety-eight participants were enrolled (49 per group); 87 were included in outcome analyses (n=40 intervention; n=47 control). At 16 weeks, there were significant between-group differences favouring the intervention: HbA1c −0.65% (95% CI: −0.99 to −0.30; p<0.0001), weight −3.26 kg (p<0.0001), BMI −1.11 kg/m² (p<0.0001), and anti-glycaemic medication requirements −0.40 MES units (p<0.0001), all with large effect sizes (Cohen’s d >0.8). Conclusion: As an adjunct to standard care, the web-based T2Diet programme significantly improved glycaemic control and clinical outcomes in adults with T2DM, demonstrating potential to expand access to dietary education and support via web-based delivery.