Effect of Weight Loss on Brain Insulin Sensitivity in Humans

Inclusion Criteria: * HbA1c \<6.5% * Age between 40 and 75 years * No intake of antidiabetic drugs or drugs for weight reduction * no steroid intake * Stable medication over 10 weeks before the start of the study Exclusion Criteria: * Persons who wear non-removable metal parts in or on the body. * Persons with reduced temperature sensitivity and / or increased sensitivity to heating of the body * Cardiovascular disease can not be ruled out, e.g. manifest coronary heart disease, heart failure greater than NYHA 2, previous heart attack, stroke condition * Persons with hearing impairment or increased sensitivity to loud noises * People with claustrophobia * Minors or non-consenting subjects are also excluded * Subjects with an operation less than 3 months * Simultaneous participation in other studies * Neurological and psychiatric disorders * Subjects with hemoglobin Hb \<11 g / dl * Hypersensitivity to any of the substances used