Levothyroxine Substitution Therapy in Hypothyroid Patients - Impact on Appetite and Food Intake

18 newly diagnosed hypothyroid female patients and 18 healthy controls age between 20 and 75 years will be recruited from the out-patients clinic in Herlev and Gentofte Hospital and the general practitioners before start of substitution therapy.

The study is devided in to three identical experimental days of approx. 6 hours. First experimental day placed before T4 treatment is initiated. Second day as soon as Thyroid Stimulating Hormone (TSH) is below 4 milli unit pr liter (mU/l). The Third experimental day after 6 months of T4 therapy.

For 5-7 days before each experimental day, the participants' physical activity energy expenditure (PAEE) will be monitored by an Actiheart® pedometer attached to the skin of the chest.

The last two days before each experimental day, the participants will follow a standardised diet following World Health Organization guidelines on energy requirements and nutrient composition according to gender, age and body weight Shortly after diagnosis patients will undergo a test panel at the first experimental day, where patients arrives fasting.

Visual analog score on satiety and thirst will be filled out continuously. REE will be measured by a CCM-express calorimeter,