Modifying the timing of breakfast improves postprandial glycaemia in people with type 2 diabetes: A randomised controlled trial.

Aims: Investigate the effects of breakfast timing on postprandial glycaemia in adults with type 2 diabetes (T2D), and the impact of a 20-min walk after breakfast.

Methods: Eleven adults with T2D (57 ± 7 y; HbA1c 7.4 ± 1%) participated in a six-week randomised crossover controlled trial comprising three 4-day conditions: Early (0700 h), Mid (0930 h) and Delayed (1200 h). After each condition, a second 4-day intervention of 20-min walk after each condition was undertaken. Standardised breakfast was provided. Interstitial glucose and physical activity were measured. Incremental area under the curve (iAUC) 2-h post-breakfast, 24-h iAUC, and fasting glucose were analysed with linear mixed-effects models. Cohen's d of the 2-h iAUC post-breakfast 20-min walk was calculated.

Results: Mid and Delayed had lower 2-h post-breakfast iAUC (p < 0.002, -57 mmol/L×2h; p < 0.02, -41 mmol/L×2h) compared to Early. There were no differences in fasting (0600 h) glucose or 24-h iAUC. There was a small effect of the 20-min walk on lowering 2-h post-breakfast iAUC for Early (d = 0.35) and Delayed (d = 0.37), with no effect in Mid.

Conclusion: In people with T2D, delaying breakfast from 0700 h to mid-morning or midday reduced postprandial glycaemia. Additional post-meal walking for 20 min had a small effect in lowering postprandial glycaemia when breakfast was at 0700 h or midday, but provided no additional benefit when breakfast was at mid-morning.