Our goal was to evaluate the effect of breakfast size and composition on body weight, glycemic control, and metabolic markers in adults with type 2 diabetes mellitus (T2DM).


59 overweight/obese adults with T2DM were randomized to one of two isocaloric diabetic diets for 3 months; big breakfast (BB), breakfast was rich in fat and protein and provided 33% of total daily energy or small breakfast (SB), breakfast was rich in carbohydrates and provided 12.5% of total daily energy.


Although body weight was reduced similarly in both groups, the BB group showed greater HbA1c and systolic blood pressure reductions (HbA1c: −4.62% vs. −1.46%, p = 0.047; SBP −9.58 vs. −2.43 mmHg; p = 0.04). T2DM medication dose was reduced in a greater proportion of the BB participants (31% vs. 0%; p = 0.002) while in the SB, a greater proportion of participants had a dose increases (16.7% vs. 3.4%; p = 0.002). Hunger scores were lower in the BB group and greater improvements in fasting glucose were observed in the BB group.


A simple dietary manipulation enriching breakfast with energy as protein and fat appears to confer metabolic benefits and might be a useful alternative for the management of T2DM.