I think the easiest - and healthiest - way is to eat a whole-food diet where nothing bad is added and nothing good is taken away. You can properly fill up and feel really satisfied on vegetables, fruits, beans, lentils, chickpeas, whole grains, nuts, seeds, herbs and spices.
It becomes a way of life so there is no cliff-edge where you return to former eating habits with the inevitable weight gain. As a bonus, this way of eating seriously improves many of the illnesses caused or made worse by modern eating habits.