12 obese subjects will receive peripheral administration of placebo and 4 escalating doses of PYY1-36 and another 12 obese subjects will receive peripheral administration of placebo and 4 escalating doses PYY3-36 on 5 different test days within one week. The patients will be tested in a single blinded dose escalating protocol. Measurements of appetite, ad libitum energy intake, blood pressure and blood sampling will be performed during the test day.