This is the first study to examine whether training before breakfast in the overnight‐fasted state is more effective in improving the health of patients with type 2 diabetes mellitus (T2DM) than after breakfast in the fed state. Thirty T2DM patients (60 ± 8 years, 33.7 ± 4.6 kg/m2) were randomly assigned to the F group (training in the overnight‐fasted state (n = 15)) and to the C group (training in the fed state (control group, n = 15)). All patients completed an 8‐week combined endurance/strength training program. Physical training significantly increased time to physical exhaustion during an endurance test (+10.4%), power output during strength tests (chest presses: +36.7% and seated rows: +37.8%), and fat‐free mass (+1.7 kg). Body fat mass (−1.9 kg), glycated hemoglobin (HbA1c) values (absolute change: −0.3%), serum insulin values (−2.5 microU/mL), the homeostatic model assessment for insulin resistance (HOMA‐IR) index (−1.1), and circulating triglyceride levels (−31 mg/dL) decreased significantly from pre‐ to post‐training. The training had no effect on body mass index, serum fasting glucose, total cholesterol, low‐density lipoprotein/high‐density lipoprotein ratio or interleukin (IL)‐6, IL‐10 and tumor necrosis factor (TNF)α levels. Analyses of variance revealed no time × group interaction for any variable (P > .05). The training was effective in improving the health of T2DM patients. However, the preliminary study's data do not provide any evidence that the nutritional state (overnight‐fasted or fed) in regular physical training plays a significant role for training‐induced adaptations in T2DM patients. Full trials (using other training protocols as well) should be conducted to gain further knowledge about the relevance of pre‐exercise breakfast ingestion.

Irisin is a promising therapeutic target in patients with type 2 diabetes mellitus (T2DM), as studies have demonstrated that irisin can induce “browning“ of adipocytes and mitigate pro-inflammatory conditions. Sex-specific changes in irisin levels have been reported in a study involving healthy men and women following physical training. The present study aims to analyze the effects of an 8-week training intervention on circulating irisin levels in patients with T2DM and to find out whether the training responses differ between T2DM men and women. Twenty-nine overweight/obese T2DM patients (19 men, 10 women; age: 46–74 years; body mass index >25 kg/m2) participated in a combined moderate-intensity endurance/strength training program (3 times a week). The irisin levels of men and women did not differ significantly. The post-training irisin levels did not differ significantly from the pre-training values, and there was no interaction effect of sex. This study shows no training-induced (sex-specific) changes in circulating irisin levels in T2DM patients. Large-scale studies using other forms of training are needed to fully clarify whether basal irisin levels can be changed in T2DM men and/or women to counteract T2DM.