2.1. Participants

Study participants were recruited through public announcements in the public health system (Brasília/Brazil). Eligibility criteria included the following: male subjects with T2DM, age 30–60 years, regular breakfast consumers (≥100 kcal ingested within 2 h of waking for ≥4 d/week), willingness to eat all test foods, no self-reported allergy to the foods provided in the study, and no self-reported sleep disorders. Patients’ medical charts were checked to identify and exclude those with any other clinically diagnosed health conditions. In addition, participants on current exogenous use of insulin, with health complications from diabetes, reported gastrointestinal disorders, and irregular intestinal rhythm (diarrhea or constipation), and smokers were excluded.

Sample size calculation was performed using G*Power software (version 3.1.9.2; Dusseldorf University, Dusseldorf, Germany) [20], considering a superiority margin of 1, a true mean difference in glucose of 5 mmol/L min (or 90 mg/dL min), and a standard deviation of 5. For achieving 80% power at the 5% level of significance, the sample size for a crossover design was 19 participants [21].