A Randomized Controlled Trial to Assess the Feasibility and Practicability of an Oatmeal Intervention in Individuals with Type 2 Diabetes: A Pilot Study in the Outpatient Sector

<b>Background/Objectives</b>: The aim of this study was to investigate the feasibility and practicability of repeated three-day sequences of a hypocaloric oat-based nutrition intervention (OI) in insulin-treated outpatients with type 2 diabetes and severe insulin resistance. <b>Methods</b>: A randomized, two-armed pilot study was conducted with three months of intervention and three months follow-up with 17 participants with insulin resistance (≥1 IU/kg body weight). Group A (<i>n</i> = 10) performed one sequence of OI; Group B (<i>n</i> = 7) performed two sequences monthly. A sequence was 3 consecutive days of oat consumption with approximately 800 kcal/d. The main objective was to assess feasibility (≥70% completers) and practicability regarding performance aspects. Biomedical parameters such as HbA1 c were observed. To evaluate the state of health, a standardized questionnaire was used (EQ-5 D). <b>Results</b>: OI was feasible (13/17 completer participants (76.5%): 70.0% Group A, 85.7% Group B). Individually perceived practicability was reported as good by 10/16 participants (62.5%). Total insulin dosage decreased from 138 ± 35 IU at baseline to 126 ± 42 IU after OI (<i>p</i> = 0.04) and 127 ± 42 IU after follow-up (<i>p</i> = 0.05). HbA1 c was lower after OI (-0.3 ± 0.1%; <i>p</i> = 0.01) in all participants. Participants in Group B tended to have greater reductions in insulin (Δ-19 IU vs. Δ-4 IU; <i>p</i> = 0.42) and weight loss (Δ-2.8 kg vs. Δ-0.2 kg; <i>p</i> = 0.65) after follow-up. Severe hypoglycemia was not observed. EQ-5 D increase not significantly after follow-up (57.2 ± 24.0% vs. 64.7 ± 21.5%; <i>p</i> = 0.21). <b>Conclusions</b>: The feasibility and practicability of OI in outpatients were demonstrated. OI frequency appears to correlate with insulin reduction and weight loss. Proper insulin dose adaptation during OI is necessary. Presumably, repeated OIs are required for substantial beneficial metabolic effects.