Can a Single Maximally Fortified Food Improve Glycaemia in Type 2 Diabetes? Randomised Crossover Trial of High‐Fibre High‐Protein Bread

ABSTRACT Objective To examine the effects of a maximally fortified high‐fibre high‐protein bread on glycaemia in free‐living adults with Type 2 diabetes. Research Design and Methods Participants were provided commercially produced high‐fibre high‐protein bread (fibre 8.1 g and protein 19.5 g/100 g) fortified with lupin flour, pea protein and wheat fibre or refined grain bread control (fibre 2.9 g and protein 10.4 g/100 g) for 2 weeks in random order, separated by a 2‐week washout. Continuous glucose monitoring (CGM), fasted blood samples, anthropometry and three‐day dietary records were collected during each intervention period. The primary outcome was postprandial glycaemia measured by all‐meal incremental area under the curve (iAUC) with CGM during both interventions. Results Thirty‐three adults (mean age 57.9 ± 12.6 years, BMI 33.1 ± 7.5 kg/m 2 , HbA1c 60.1 ± 15.1 mmol/mol) were randomised, with 31 completing both interventions. Dietary energy intake was comparable between interventions, while fibre and protein intakes were higher during the high‐fibre high‐protein bread intervention. Compared with control bread, the high‐fibre high‐protein bread improved glycaemic metrics, including all‐meal iAUC (−21 mmol L −1 min −1 [95% CI: −39 to −3]), time in range (4.1% [95% CI: 2.2–6.1]), time above range (−4.3% [95% CI: −6.3 to −2.4]) and glycaemic variability (CONGA −0.4 [95% CI: −0.5 to −0.2]). Systolic (−7.2 mmHg [95% CI: −11.2 to −3.2]) and diastolic (−7.2 mmHg [95% CI: −9.9 to −4.6]) blood pressure also improved. No differences were observed between interventions for anthropometry, lipid profile or C‐reactive protein. Conclusions Use of a single food, maximally fortified with fibre and protein, improved glycaemia in type 2 diabetes management compared with an unfortified equivalent over 2 weeks. Reformulation of common staples with these two nutrients presents a practical and scalable strategy for manufacturers to support diabetes management.