Insulin resistance is a central feature of Diabetes mellitus type 2 (Stumvoll et al. 2005). Hypo- and hyperglycemic states are associated with adverse inpatient outcomes (ADA et al. 2006 Diab Care) and with the development of microvascular complications (UKPDS 34 Lancet 1998).

A long known therapy for the acute treatment of patients with deteriorated glucose metabolism and insulin resistance are carbohydrate days. The principle of the therapy was firstly introduced in 1903 by Carl von Noorden (Noorden et al. 1903). The diabetic patients were treated for several days with a carbohydrate rich diet with fat restriction. Surprisingly, this resulted in an amelioration of glucosuria. Today it's still a valuable tool for patients with uncontrollable diabetes mellitus and severe insulin resistance (Willms B. 1989). But up to now there has been no systemic evaluation of carbohydrate days in patients with deteriorated Diabetes mellitus and insulin resistance.

The investigators conducted a pilot study with 14 patients to evaluate the efficacy of two days of oatmeal on insulin resistance and glucose metabolism in an acute clinical setting and after a four week outpatient period. Inclusion criteria were type 2 diabetes with deteriorated glucose metabolism, insulin resistance defined as an insulin dosage of more than 1 U per day and kg bodyweight. Within this pilot trial the investigators found a marked decrease of insulin requirements (~40%) and mean daily blood glucose to a mean blood glucose of 114.7±36.7 mg/dl in the acute setting as well as after the four week outpatient period (Lammert et al. 2006).

The most important shortcomings of this study were the hypocaloric interventions in both groups (diabetes-adapted diet: 1500kcal/d vs. oatmeal 1200kcal/d) making it difficult to attribute the observed effects to oatmeal alone as well as the uncontrolled nature. These design flaws have been addressed within this new clinical trial. The investigators plan an open label, cross-over study with isocaloric interventions (oatmeal and diabetes-adapted diet: ~ 1200kcal/d). The intervention comprises two days of oatmeal (third and fourth day) within a 5 day hospital stay. The control is only treated with 5 days of diabetes adapted diet. Thereafter, the patients are followed every four weeks for an overall of 16 weeks.

Inclusion Criteria:

• diabetes mellitus 2
• insulin therapy
• stable therapy modality within the last 3 months
• deteriorated glucose metabolism (Hba1c > 7%)
• insulin resistance, defined as more than 1 unit of insulin per kg and day

Exclusion Criteria:

• acute vascular event within the last 3 months
• planed weight reducing therapy
• acute and chronic inflammatory disease
• therapy with corticosteroids
• pregnancy