This chapter gives an overview of work on porcine adipose tissue that was performed at Eindhoven University of Technology. It demonstrates that only at very small strains, far away from the physiological strains we experience in daily live, the behavior is more or less linear and can be described with standard constitutive models. Long term oscillatory behavior and the behavior at large strains is more complex and currently a highly unexplored area. Adipose tissue is able to change its micro-structure such that at high strains or long times of harmonic excitation the material behavior changes drastically. This structural change is reversible after long periods of rest. The chapter is largely based on two papers by Geerligs et al. [3, 4].