**1. Introduction**

"Adipositas" or "obesity" remains an increasing problem, escalating with alarming speed worldwide. As this introductory chapter is written, it is estimated that there exist between 380 and 500 million obese people worldwide (depending on the definition of obesity). Obesity is normally defined as: "A condition of abnormal or excess body fat (triglycerides), which is associated with a number of disorders of life-threatening or debilitating disorders or diseases".
